Menke-Hennekam syndrome; delineation of domain-specific subtypes with distinct clinical and DNA methylation profiles

CREB-binding protein (CBP, encoded by CREBBP) and its paralog E1A-associated protein (p300, encoded by EP300) are involved in histone acetylation and transcriptional regulation. Variants that produce a null allele or disrupt the catalytic domain of either protein cause Rubinstein-Taybi syndrome (RSTS), while pathogenic missense and in-frame indel variants in parts of exons 30 and 31 cause phenotypes recently described as Menke-Hennekam syndrome (MKHK). To distinguish MKHK subtypes and define their characteristics, molecular and extended clinical data on 82 individuals (54 unpublished) with variants affecting CBP (n = 71) or p300 (n = 11) (NP_004371.2 residues 1,705-1,875 and NP_001420.2 residues 1,668-1,833, respectively) were summarized. Additionally, genome-wide DNA methylation profiles were assessed in DNA extracted from whole peripheral blood from 54 individuals. Most variants clustered closely around the zinc-binding residues of two zinc-finger domains (ZZ and TAZ2) and within the first α helix of the fourth intrinsically disordered linker (ID4) of CBP/p300. Domain-specific methylation profiles were discerned for the ZZ domain in CBP/p300 (found in nine out of 10 tested individuals) and TAZ2 domain in CBP (in 14 out of 20), while a domain-specific diagnostic episignature was refined for the ID4 domain in CBP/p300 (in 21 out of 21). Phenotypes including intellectual disability of varying degree and distinct physical features were defined for each of the regions. These findings demonstrate existence of at least three MKHK subtypes, which are domain specific (MKHK-ZZ, MKHK-TAZ2, and MKHK-ID4) rather than gene specific (CREBBP/EP300). DNA methylation episignatures enable stratification of molecular pathophysiologic entities within a gene or across a family of paralogous genes.

Genetic complexity of diagnostically unresolved Ehlers-Danlos syndrome

BACKGROUND

The Ehlers-Danlos syndromes (EDS) are heritable disorders of connective tissue (HDCT), reclassified in the 2017 nosology into 13 subtypes. The genetic basis for hypermobile Ehlers-Danlos syndrome (hEDS) remains unknown.

METHODS

Whole exome sequencing (WES) was undertaken on 174 EDS patients recruited from a national diagnostic service for complex EDS and a specialist clinic for hEDS. Patients had already undergone expert phenotyping, laboratory investigation and gene sequencing, but were without a genetic diagnosis. Filtered WES data were reviewed for genes underlying Mendelian disorders and loci reported in EDS linkage, transcriptome and genome-wide association studies (GWAS). A genetic burden analysis (Minor Allele Frequency (MAF) <0.05) incorporating 248 Avon Longitudinal Study of Parents and Children (ALSPAC) controls sequenced as part of the UK10K study was undertaken using TASER methodology.

RESULTS

Heterozygous pathogenic (P) or likely pathogenic (LP) variants were identified in known EDS and Loeys-Dietz (LDS) genes. Multiple variants of uncertain significance where segregation and functional analysis may enable reclassification were found in genes associated with EDS, LDS, heritable thoracic aortic disease (HTAD), Mendelian disorders with EDS symptomatology and syndromes with EDS-like features. Genetic burden analysis revealed a number of novel loci, although none reached the threshold for genome-wide significance. Variants with biological plausibility were found in genes and pathways not currently associated with EDS or HTAD.

CONCLUSIONS

We demonstrate the clinical utility of large panel-based sequencing and WES for patients with complex EDS in distinguishing rare EDS subtypes, LDS and related syndromes. Although many of the P and LP variants reported in this cohort would be identified with current panel testing, they were not at the time of this study, highlighting the use of extended panels and WES as a clinical tool for complex EDS. Our results are consistent with the complex genetic architecture of EDS and suggest a number of novel hEDS and HTAD candidate genes and pathways.

From diagnosis of colorectal cancer to diagnosis of Lynch syndrome: The RM Partners quality improvement project

AIM

The UK National Institute for Health and Care Excellence guideline DG27 recommends universal testing for Lynch syndrome (LS) in all newly diagnosed colorectal cancer (CRC) patients. However, DG27 guideline implementation varies significantly by geography. This quality improvement project (QIP) was developed to measure variation and deliver an effective diagnostic pathway from diagnosis of CRC to diagnosis of LS within the RM Partners (RMP) West London cancer alliance.

METHOD

RM Partners includes a population of 4 million people and incorporates nine CRC multidisciplinary teams (MDTs), overseen by a Pathway Group, and three regional genetic services, managing approximately 1500 new CRC cases annually. A responsible LS champion was nominated within each MDT. A regional project manager and nurse practitioner were appointed to support the LS champions, to develop online training packages and patient consultation workshops. MDTs were supported to develop an 'in-house' mainstreaming service to offer genetic testing in their routine oncology clinics. Baseline data were collected through completion of the LS pathway audit of the testing pathway in 30 consecutive CRC patients from each CRC MDT, with measurement of each step of the testing pathway. Areas for improvement in each MDT were identified, delivered by the local champion and supported by the project team.

RESULTS

Overall, QIP measurables improved following the intervention. The Wilcoxon signed rank test revealed significant differences with strong effect sizes on the percentile of CRC cases undergoing mismatch repair (MMR) testing in endoscopic biopsies (p = 0.008), further testing with either methylation or BRAF V600E (p = 0/03) and in effective referral for genetic testing (from 10% to 74%; p = 0.02). During the QIP new mainstreaming services were developed, alongside the implementation of systematic and robust testing pathways. These pathways were tailored to the needs of each CRC team to ensure that patients with a diagnosis of CRC had access to testing for LS. Online training packages were produced which remain freely accessible for CRC teams across the UK.

CONCLUSION

The LS project was completed by April 2022. We have implemented a systematic approach with workforce transformation to facilitate identification and 'mainstreamed' genetic diagnosis of LS. This work has contributed to the development of a National LS Transformation Project in England which recommends local leadership within cancer teams to ensure delivery of diagnosis of LS and integration of genomics into clinical practice.

Noncoding variants alter GATA2 expression in rhombomere 4 motor neurons and cause dominant hereditary congenital facial paresis

Hereditary congenital facial paresis type 1 (HCFP1) is an autosomal dominant disorder of absent or limited facial movement that maps to chromosome 3q21-q22 and is hypothesized to result from facial branchial motor neuron (FBMN) maldevelopment. In the present study, we report that HCFP1 results from heterozygous duplications within a neuron-specific GATA2 regulatory region that includes two enhancers and one silencer, and from noncoding single-nucleotide variants (SNVs) within the silencer. Some SNVs impair binding of NR2F1 to the silencer in vitro and in vivo and attenuate in vivo enhancer reporter expression in FBMNs. Gata2 and its effector Gata3 are essential for inner-ear efferent neuron (IEE) but not FBMN development. A humanized HCFP1 mouse model extends Gata2 expression, favors the formation of IEEs over FBMNs and is rescued by conditional loss of Gata3. These findings highlight the importance of temporal gene regulation in development and of noncoding variation in rare mendelian disease.

Expanding the phenotype of children presenting with hypoventilation with biallelic TBCK pathogenic variants and literature review

Individuals with biallelic TBCK pathogenic variants present in infancy with distinctive facial features, profound hypotonia, severe intellectual impairment and epilepsy. Although rare, it may mimic other neurogenetic disorders leading to extensive investigations. Improved understanding of the clinical phenotype can support early monitoring of complications due to respiratory insufficiency. We present six individuals who were found to have pathogenic biallelic TBCK variants. The clinico-radiological and diagnostic records were reviewed. Five individuals were diagnosed with hypoventilation, requiring respiratory support, highlighting the need for early respiratory surveillance. Characteristic brain imaging in our cohort included periventricular leukomalacia-like changes. We recommend screening for TBCK in hypotonic children with periventricular leukomalacia-like changes, particularly in the absence of prematurity.

Oral characteristics in adult individuals with periodontal Ehlers-Danlos syndrome

AIM

Periodontal Ehlers-Danlos syndrome (pEDS) is a monogenic type of Ehlers-Danlos syndrome characterized by periodontal destruction at a young age. The present study aimed to document the oral phenotype of pEDS based on prospective clinical investigations.

MATERIALS AND METHODS

Thirty-five adult individuals from 13 families with a clinically and genetically confirmed diagnosis of pEDS underwent a systematic oral assessment.

RESULTS

Periodontitis stage 3 or 4 or edentulism due to periodontal destruction were diagnosed in 94% of the individuals. First permanent tooth loss was reported at the age of 21.5 years (median; range 13-43 years). Deep periodontal pockets were infrequent, with 94% measuring &lt;4 mm. However, there was increased clinical attachment loss (CAL) averaging 8 mm (range 4-13 mm), and the probability of being edentate between the age of 35 and 44 years was 28-47% compared with less than 0.25% of the general population. Radiographic anomalous findings were only found in a portion of subjects and consisted of fused roots of maxillary second molars (81%), root hypoplasia (57%), taurodontism (26%) and tooth rotation of premolars (67%). As such, radiographic findings are not considered common characteristics of pEDS.

CONCLUSIONS

Characteristic oral traits of pEDS in adults are severe CAL with shallow probing depths and marked gingival recession. This is complemented by a lack of attached gingiva. These indications need to be paralleled by genetic analyses to diagnose pEDS unambiguously.

Randomised trial of population-based BRCA testing in Ashkenazi Jews: long-term secondary lifestyle behavioural outcomes

OBJECTIVE

Ashkenazi-Jewish (AJ) population-based BRCA testing is acceptable, cost-effective and amplifies primary prevention for breast & ovarian cancer. However, data describing lifestyle impact are lacking. We report long-term results of population-based BRCA testing on lifestyle behaviour and cancer risk perception.

DESIGN

Two-arm randomised controlled trials (ISRCTN73338115, GCaPPS): (a) population-screening (PS); (b) family history (FH)/clinical criteria testing.

SETTING

North London AJ-population.

POPULATION/SAMPLE

AJ women/men >18 years.

EXCLUSIONS

prior BRCA testing or first-degree relatives of BRCA-carriers.

METHODS

Participants were recruited through self-referral. All participants received informed pre-test genetic counselling. The intervention included genetic testing for three AJ BRCA-mutations: 185delAG(c.68_69delAG), 5382insC(c.5266dupC) and 6174delT(c.5946delT). This was undertaken for all participants in the PS arm and participants fulfilling FH/clinical criteria in the FH arm. Patients filled out customised/validated questionnaires at baseline/1-year/2-year/3-year follow-ups. Generalised linear-mixed models adjusted for covariates and appropriate contrast tests were used for between-group/within-group analysis of lifestyle and behavioural outcomes along with evaluating factors associated with these outcomes. Outcomes are adjusted for multiple testing (Bonferroni method), with P < 0.0039 considered significant.

OUTCOME MEASURES

Lifestyle/behavioural outcomes at baseline/1-year/2-year/3-year follow-ups.

RESULTS

1034 participants were randomised to PS (n = 530) or FH (n = 504) arms. No significant difference was identified between PS- and FH-based BRCA testing approaches in terms of dietary fruit/vegetable/meat consumption, vitamin intake, alcohol quantity/ frequency, smoking behaviour (frequency/cessation), physical activity/exercise or routine breast mammogram screening behaviour, with outcomes not affected by BRCA test result. Cancer risk perception decreased with time following BRCA testing, with no difference between FH/PS approaches, and the perception of risk was lowest in BRCA-negative participants. Men consumed fewer fruits/vegetables/vitamins and more meat/alcohol than women (P < 0.001).

CONCLUSION

Population-based and FH-based AJ BRCA testing have similar long-term lifestyle impacts on smoking, alcohol, dietary fruit/vegetable/meat/vitamin, exercise, breast screening participation and reduced cancer risk perception.

The avoiding late diagnosis of ovarian cancer (ALDO) project; a pilot national surveillance programme for women with pathogenic germline variants inBRCA1andBRCA2

Background

Our study aimed to establish ‘real-world’ performance and cost-effectiveness of ovarian cancer (OC) surveillance in women with pathogenic germlineBRCA1/2variants who defer risk-reducing bilateral salpingo-oophorectomy (RRSO).

Methods

Our study recruited 875 femaleBRCA1/2-heterozygotes at 13 UK centres and via an online media campaign, with 767 undergoing at least one 4-monthly surveillance test with the Risk of Ovarian Cancer Algorithm (ROCA) test. Surveillance performance was calculated with modelling of occult cancers detected at RRSO. The incremental cost-effectiveness ratio (ICER) was calculated using Markov population cohort simulation.

Results

Our study identified 8 OCs during 1277 women screen years: 2 occult OCs at RRSO (both stage 1a), and 6 screen-detected; 3 of 6 (50%) were ≤stage 3a and 5 of 6 (83%) were completely surgically cytoreduced. Modelled sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for OC were 87.5% (95% CI, 47.3 to 99.7), 99.9% (99.9–100), 75% (34.9–96.8) and 99.9% (99.9–100), respectively. The predicted number of quality-adjusted life years (QALY) gained by surveillance was 0.179 with an ICER cost-saving of -£102,496/QALY.

Conclusion

OC surveillance for women deferring RRSO in a ‘real-world’ setting is feasible and demonstrates similar performance to research trials; it down-stages OC, leading to a high complete cytoreduction rate and is cost-saving in the UK National Health Service (NHS) setting. While RRSO remains recommended management, ROCA-based surveillance may be considered for femaleBRCA-heterozygotes who are deferring such surgery.

Analysis of rare disruptive germline mutations in 2,135 enriched BRCA-negative breast cancers excludes additional high-impact susceptibility genes

BACKGROUND

Breast cancer has a significant heritable basis, of which approximately 60% remains unexplained. Testing for BRCA1/BRCA2 offers useful discrimination of breast cancer risk within families, and identification of additional breast cancer susceptibility genes could offer clinical utility.

PATIENTS AND METHODS

We included 2,135 invasive breast cancer cases recruited via the BOCS study, a retrospective UK study of familial breast cancer.

ELIGIBILITY CRITERIA

female, BRCA-negative, white European ethnicity, and one of: i) breast cancer family history, ii) bilateral disease, iii) young age of onset (<30 years), iv) concomitant ovarian cancer. We undertook exome sequencing of cases and performed gene-level burden testing of rare damaging variants against those from 51,377 ethnicity-matched population controls from gnomAD.

RESULTS

159/2135 (7.4%) cases had a qualifying variant in an established breast cancer susceptibility gene, with minimal evidence of signal in other cancer susceptibility genes. Known breast cancer susceptibility genes PALB2, CHEK2 and ATM were the only genes to retain statistical significance after correcting for multiple testing. Due to the enrichment of hereditary cases in the series, we had good power (>80%) to detect a gene of BRCA1-like risk (odds ratio = 10.6) down to a population minor allele frequency of 4.6 x 10^-5 (1 in 10,799, less than one tenth that of BRCA1)and of PALB2-like risk (odds ratio = 5.0) down to a population minor allele frequency of 2.8 x 10^-4 (1 in 1,779, less than half that of PALB2). Power was lower for identification of novel moderate penetrance genes (odds ratio = 2-3) like CHEK2 and ATM.

CONCLUSIONS

This is the largest case-control whole-exome analysis of enriched breast cancer published to date. Whilst additional breast cancer susceptibility genes likely exist, those of high penetrance are likely to be of very low mutational frequency. Contention exists regarding the clinical utility of such genes.

SDHC phaeochromocytoma and paraganglioma: A UK-wide case series

OBJECTIVE

Phaeochromocytomas and paragangliomas (PPGL) are rare, but strongly heritable tumours. Variants in succinate dehydrogenase (SDH) subunits are identified in approximately 25% of cases. However, clinical and genetic information of patients with SDHC variants are underreported.

DESIGN

This retrospective case series collated data from 18 UK Genetics and Endocrinology departments.

PATIENTS

Both asymptomatic and disease-affected patients with confirmed SDHC germline variants are included.

MEASUREMENTS

Clinical data including tumour type and location, surveillance outcomes and interventions, SDHC genetic variant assessment, interpretation, and tumour risk calculation.

RESULTS

We report 91 SDHC cases, 46 probands and 45 non-probands. Fifty-one cases were disease-affected. Median age at genetic diagnosis was 43 years (range: 11-79). Twenty-four SDHC germline variants were identified including six novel variants. Head and neck paraganglioma (HNPGL, n = 30, 65.2%), extra-adrenal paraganglioma (EAPGL, n = 13, 28.2%) and phaeochromocytomas (PCC) (n = 3, 6.5%) were present. One case had multiple PPGLs. Malignant disease was reported in 19.6% (9/46). Eight cases had non-PPGL SDHC-associated tumours, six gastrointestinal stromal tumours (GIST) and two renal cell cancers (RCC). Cumulative tumour risk (95% CI) at age 60 years was 0.94 (CI: 0.79-0.99) in probands, and 0.16 (CI: 0-0.31) in non-probands, respectively.

CONCLUSIONS

This study describes the largest cohort of 91 SDHC patients worldwide. We confirm disease-affected SDHC variant cases develop isolated HNPGL disease in nearly 2/3 of patients, EAPGL and PCC in 1/3, with an increased risk of GIST and RCC. One fifth developed malignant disease, requiring comprehensive lifelong tumour screening and surveillance.

Breast and Prostate Cancer Risks for Male BRCA1 and BRCA2 Pathogenic Variant Carriers Using Polygenic Risk Scores

BACKGROUND

Recent population-based female breast cancer and prostate cancer polygenic risk scores (PRS) have been developed. We assessed the associations of these PRS with breast and prostate cancer risks for male BRCA1 and BRCA2 pathogenic variant carriers.

METHODS

483 BRCA1 and 1318 BRCA2 European ancestry male carriers were available from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). A 147-single nucleotide polymorphism (SNP) prostate cancer PRS (PRSPC) and a 313-SNP breast cancer PRS were evaluated. There were 3 versions of the breast cancer PRS, optimized to predict overall (PRSBC), estrogen receptor (ER)-negative (PRSER-), or ER-positive (PRSER+) breast cancer risk.

RESULTS

PRSER+ yielded the strongest association with breast cancer risk. The odds ratios (ORs) per PRSER+ standard deviation estimates were 1.40 (95% confidence interval [CI] =1.07 to 1.83) for BRCA1 and 1.33 (95% CI = 1.16 to 1.52) for BRCA2 carriers. PRSPC was associated with prostate cancer risk for BRCA1 (OR = 1.73, 95% CI = 1.28 to 2.33) and BRCA2 (OR = 1.60, 95% CI = 1.34 to 1.91) carriers. The estimated breast cancer odds ratios were larger after adjusting for female relative breast cancer family history. By age 85 years, for BRCA2 carriers, the breast cancer risk varied from 7.7% to 18.4% and prostate cancer risk from 34.1% to 87.6% between the 5th and 95th percentiles of the PRS distributions.

CONCLUSIONS

Population-based prostate and female breast cancer PRS are associated with a wide range of absolute breast and prostate cancer risks for male BRCA1 and BRCA2 carriers. These findings warrant further investigation aimed at providing personalized cancer risks for male carriers and informing clinical management.

Jewish cultural and religious factors and uptake of population-based BRCA testing across denominations: a cohort study

OBJECTIVE

To evaluate the association of Jewish cultural and religious identity and denominational affiliation with interest in, intention to undertake and uptake of population-based BRCA (Breast Cancer Gene)-testing.

DESIGN

Cohort-study set within recruitment to GCaPPS-trial (ISRCTN73338115).

SETTING

London Ashkenazi-Jewish (AJ) population.

POPULATION OR SAMPLE

AJ men and women, >18 years.

METHODS

Participants were self-referred, and attended recruitment clinics (clusters) for pre-test counselling. Subsequently consenting individuals underwent BRCA testing. Participants self-identified to one Jewish denomination: Conservative/Liberal/Reform/Traditional/Orthodox/Unaffiliated. Validated scales measured Jewish Cultural-Identity (JI) and Jewish Religious-identity (JR). Four-item Likert-scales analysed initial 'interest' and 'intention to test' pre-counselling. Item-Response-Theory and graded-response models, modelled responses to JI and JR scales. Ordered/multinomial logistic regression modelling evaluated association of JI-scale, JR-scale and Jewish Denominational affiliation on interest, intention and uptake of BRCA testing.

MAIN OUTCOME MEASURES

Interest, intention, uptake of BRCA testing.

RESULTS

In all, 935 AJ women/men of mean age = 53.8 (S.D = 15.02) years, received pre-test education and counselling through 256 recruitment clinic clusters (median cluster size = 3). Denominational affiliations included Conservative/Masorti = 91 (10.2%); Liberal = 82 (9.2%), Reform = 135 (15.1%), Traditional = 212 (23.7%), Orthodox = 239 (26.7%); and Unaffiliated/Non-practising = 135 (15.1%). Overall BRCA testing uptake was 88%. Pre-counselling, 96% expressed interest and 60% intention to test. JI and JR scores were highest for Orthodox, followed by Conservative/Masorti, Traditional, Reform, Liberal and Unaffiliated Jewish denominations. Regression modelling showed no significant association between overall Jewish Cultural or Religious Identity with either interest, intention or uptake of BRCA testing. Interest, intention and uptake of BRCA testing was not significantly associated with denominational affiliation.

CONCLUSIONS

Jewish religious/cultural identity and denominational affiliation do not appear to influence interest, intention or uptake of population-based BRCA testing. BRCA testing was robust across all Jewish denominations.

TWEETABLE ABSTRACT

Jewish cultural/religious factors do not affect BRCA testing, with robust uptake seen across all denominational affiliations.

A prospective prostate cancer screening programme for men with pathogenic variants in mismatch repair genes (IMPACT): initial results from an international prospective study

BACKGROUND

Lynch syndrome is a rare familial cancer syndrome caused by pathogenic variants in the mismatch repair genes MLH1, MSH2, MSH6, or PMS2, that cause predisposition to various cancers, predominantly colorectal and endometrial cancer. Data are emerging that pathogenic variants in mismatch repair genes increase the risk of early-onset aggressive prostate cancer. The IMPACT study is prospectively assessing prostate-specific antigen (PSA) screening in men with germline mismatch repair pathogenic variants. Here, we report the usefulness of PSA screening, prostate cancer incidence, and tumour characteristics after the first screening round in men with and without these germline pathogenic variants.

METHODS

The IMPACT study is an international, prospective study. Men aged 40-69 years without a previous prostate cancer diagnosis and with a known germline pathogenic variant in the MLH1, MSH2, or MSH6 gene, and age-matched male controls who tested negative for a familial pathogenic variant in these genes were recruited from 34 genetic and urology clinics in eight countries, and underwent a baseline PSA screening. Men who had a PSA level higher than 3·0 ng/mL were offered a transrectal, ultrasound-guided, prostate biopsy and a histopathological analysis was done. All participants are undergoing a minimum of 5 years' annual screening. The primary endpoint was to determine the incidence, stage, and pathology of screening-detected prostate cancer in carriers of pathogenic variants compared with non-carrier controls. We used Fisher's exact test to compare the number of cases, cancer incidence, and positive predictive values of the PSA cutoff and biopsy between carriers and non-carriers and the differences between disease types (ie, cancer vs no cancer, clinically significant cancer vs no cancer). We assessed screening outcomes and tumour characteristics by pathogenic variant status. Here we present results from the first round of PSA screening in the IMPACT study. This study is registered with ClinicalTrials.gov, NCT00261456, and is now closed to accrual.

FINDINGS

Between Sept 28, 2012, and March 1, 2020, 828 men were recruited (644 carriers of mismatch repair pathogenic variants [204 carriers of MLH1, 305 carriers of MSH2, and 135 carriers of MSH6] and 184 non-carrier controls [65 non-carriers of MLH1, 76 non-carriers of MSH2, and 43 non-carriers of MSH6]), and in order to boost the sample size for the non-carrier control groups, we randomly selected 134 non-carriers from the BRCA1 and BRCA2 cohort of the IMPACT study, who were included in all three non-carrier cohorts. Men were predominantly of European ancestry (899 [93%] of 953 with available data), with a mean age of 52·8 years (SD 8·3). Within the first screening round, 56 (6%) men had a PSA concentration of more than 3·0 ng/mL and 35 (4%) biopsies were done. The overall incidence of prostate cancer was 1·9% (18 of 962; 95% CI 1·1-2·9). The incidence among MSH2 carriers was 4·3% (13 of 305; 95% CI 2·3-7·2), MSH2 non-carrier controls was 0·5% (one of 210; 0·0-2·6), MSH6 carriers was 3·0% (four of 135; 0·8-7·4), and none were detected among the MLH1 carriers, MLH1 non-carrier controls, and MSH6 non-carrier controls. Prostate cancer incidence, using a PSA threshold of higher than 3·0 ng/mL, was higher in MSH2 carriers than in MSH2 non-carrier controls (4·3% vs 0·5%; p=0·011) and MSH6 carriers than MSH6 non-carrier controls (3·0% vs 0%; p=0·034). The overall positive predictive value of biopsy using a PSA threshold of 3·0 ng/mL was 51·4% (95% CI 34·0-68·6), and the overall positive predictive value of a PSA threshold of 3·0 ng/mL was 32·1% (20·3-46·0).

INTERPRETATION

After the first screening round, carriers of MSH2 and MSH6 pathogenic variants had a higher incidence of prostate cancer compared with age-matched non-carrier controls. These findings support the use of targeted PSA screening in these men to identify those with clinically significant prostate cancer. Further annual screening rounds will need to confirm these findings.

FUNDING

Cancer Research UK, The Ronald and Rita McAulay Foundation, the National Institute for Health Research support to Biomedical Research Centres (The Institute of Cancer Research and Royal Marsden NHS Foundation Trust; Oxford; Manchester and the Cambridge Clinical Research Centre), Mr and Mrs Jack Baker, the Cancer Council of Tasmania, Cancer Australia, Prostate Cancer Foundation of Australia, Cancer Council of Victoria, Cancer Council of South Australia, the Victorian Cancer Agency, Cancer Australia, Prostate Cancer Foundation of Australia, Asociación Española Contra el Cáncer (AECC), the Instituto de Salud Carlos III, Fondo Europeo de Desarrollo Regional (FEDER), the Institut Català de la Salut, Autonomous Government of Catalonia, Fundação para a Ciência e a Tecnologia, National Institutes of Health National Cancer Institute, Swedish Cancer Society, General Hospital in Malmö Foundation for Combating Cancer.

PIGG variant pathogenicity assessment reveals characteristic features within 19 families

PURPOSE

Phosphatidylinositol Glycan Anchor Biosynthesis, class G (PIGG) is an ethanolamine phosphate transferase catalyzing the modification of glycosylphosphatidylinositol (GPI). GPI serves as an anchor on the cell membrane for surface proteins called GPI-anchored proteins (GPI-APs). Pathogenic variants in genes involved in the biosynthesis of GPI cause inherited GPI deficiency (IGD), which still needs to be further characterized.

METHODS

We describe 22 individuals from 19 unrelated families with biallelic variants in PIGG. We analyzed GPI-AP surface levels on granulocytes and fibroblasts for three and two individuals, respectively. We demonstrated enzymatic activity defects for PIGG variants in vitro in a PIGG/PIGO double knockout system.

RESULTS

Phenotypic analysis of reported individuals reveals shared PIGG deficiency-associated features. All tested GPI-APs were unchanged on granulocytes whereas CD73 level in fibroblasts was decreased. In addition to classic IGD symptoms such as hypotonia, intellectual disability/developmental delay (ID/DD), and seizures, individuals with PIGG variants of null or severely decreased activity showed cerebellar atrophy, various neurological manifestations, and mitochondrial dysfunction, a feature increasingly recognized in IGDs. Individuals with mildly decreased activity showed autism spectrum disorder.

CONCLUSION

This in vitro system is a useful method to validate the pathogenicity of variants in PIGG and to study PIGG physiological functions.

Results from London Regional Clinical Genetics services over a 5-year period on germline TP53 testing in women diagnosed with breast cancer at <30 years

BACKGROUND

The most common cancer diagnosed in germline TP53 pathogenic variant (PV) carriers is premenopausal breast cancer. An increased rate of breast tumour HER2 positivity has been reported in this group. Screening for breast/other cancers is recommended in PV carriers.

OBJECTIVES

1. To assess the frequency of germline TP53 PVs reported diagnostically in women with breast cancer at <30 years of age.2. To evaluate the impact of personal/family history and HER2 status on the likelihood of germline TP53 pathogenic/likely pathogenic variant (PV/LPV) identification.

METHODS

Genetic test results from patients undergoing diagnostic germline TP53 tests between 2012 and 2017 in the four London Regional Clinical Genetics Services were reviewed. Clinical/pathology data and family history were extracted from genetics files for women diagnosed with breast cancer at <30 years.

RESULTS

The overall germline TP53 PV/LPV variant detection rate was 9/270=3.3% in all women diagnosed with breast cancer at <30 years and 2/171=1.2% in those with no second/subsequent cancer diagnosis or family history of TP53-spectrum cancers. Breast cancers were significantly more likely to be HER2-positive in TP53 PV/LPV carriers than in non-carriers (p=0.00006).

CONCLUSIONS

Germline TP53 PVs/LPVs are uncommon among women diagnosed with breast cancer aged <30 years without other relevant personal or family cancer history but have an important clinical impact when identified.

Clinical delineation, sex differences, and genotype-phenotype correlation in pathogenic KDM6A variants causing X-linked Kabuki syndrome type 2

Purpose

The variant spectrum and the phenotype of X-linked Kabuki syndrome type 2 (KS2) are poorly understood.

Methods

Genetic and clinical details of new and published individuals with pathogenic KDM6A variants were compiled and analyzed.

Results

Sixty-one distinct pathogenic KDM6A variants (50 truncating, 11 missense) from 80 patients (34 males, 46 females) were identified. Missense variants clustered in the TRP 2, 3, 7 and Jmj-C domains. Truncating variants were significantly more likely to be de novo. Thirteen individuals had maternally inherited variants and one had a paternally inherited variant. Neonatal feeding difficulties, hypoglycemia, postnatal growth retardation, poor weight gain, motor delay, intellectual disability (ID), microcephaly, congenital heart anomalies, palate defects, renal malformations, strabismus, hearing loss, recurrent infections, hyperinsulinism, seizures, joint hypermobility, and gastroesophageal reflux were frequent clinical findings. Facial features of over a third of patients were not typical for KS. Males were significantly more likely to be born prematurely, have shorter stature, and severe developmental delay/ID.

Conclusion

We expand the KDM6A variant spectrum and delineate the KS2 phenotype. We demonstrate that the variability of the KS2 phenotypic depends on sex and the variant type. We also highlight the overlaps and differences between the phenotypes of KS2 and KS1.

Variants in GNAI1 cause a syndrome associated with variable features including developmental delay, seizures, and hypotonia

PURPOSE

Neurodevelopmental disorders (NDDs) encompass a spectrum of genetically heterogeneous disorders with features that commonly include developmental delay, intellectual disability, and autism spectrum disorders. We sought to delineate the molecular and phenotypic spectrum of a novel neurodevelopmental disorder caused by variants in the GNAI1 gene.

METHODS

Through large cohort trio-based exome sequencing and international data-sharing, we identified 24 unrelated individuals with NDD phenotypes and a variant in GNAI1, which encodes the inhibitory Gαi1 subunit of heterotrimeric G-proteins. We collected detailed genotype and phenotype information for each affected individual.

RESULTS

We identified 16 unique variants in GNAI1 in 24 affected individuals; 23 occurred de novo and 1 was inherited from a mosaic parent. Most affected individuals have a severe neurodevelopmental disorder. Core features include global developmental delay, intellectual disability, hypotonia, and epilepsy.

CONCLUSION

This collaboration establishes GNAI1 variants as a cause of NDDs. GNAI1-related NDD is most often characterized by severe to profound delays, hypotonia, epilepsy that ranges from self-limiting to intractable, behavior problems, and variable mild dysmorphic features.

Prostate Cancer Risk by BRCA2 Genomic Regions

A BRCA2 prostate cancer cluster region (PCCR) was recently proposed (c.7914 to 3') wherein pathogenic variants (PVs) are associated with higher prostate cancer (PCa) risk than PVs elsewhere in the BRCA2 gene. Using a prospective cohort study of 447 male BRCA2 PV carriers recruited in the UK and Ireland from 1998 to 2016, we estimated standardised incidence ratios (SIRs) compared with population incidences and assessed variation in risk by PV location. Carriers of PVs in the PCCR had a PCa SIR of 8.33 (95% confidence interval [CI] 4.46-15.6) and were at a higher risk of PCa than carriers of other BRCA2 PVs (SIR = 3.31, 95% CI 1.97-5.57; hazard ratio = 2.34, 95% CI 1.09-5.03). PCCR PV carriers had an estimated cumulative PCa risk of 44% (95% CI 23-72%) by the age of 75 yr and 78% (95% CI 54-94%) by the age of 85 yr. Our results corroborate the existence of a PCCR in BRCA2 in a prospective cohort. PATIENT SUMMARY: In this report, we investigated whether the risk of prostate cancer for men with a harmful mutation in the BRCA2 gene differs based on where in the gene the mutation is located. We found that men with mutations in one region of BRCA2 had a higher risk of prostate cancer than men with mutations elsewhere in the gene.

UKCGG Consensus Group guidelines for the management of patients with constitutional TP53 pathogenic variants

Constitutional pathogenic variants in TP53 are associated with Li-Fraumeni syndrome or the more recently described heritable TP53-related cancer syndrome and are associated with increased lifetime risks of a wide spectrum of cancers. Due to the broad tumour spectrum, surveillance for this patient group has been limited. To date, the only recommendation in the UK has been for annual breast MRI in women; however, more recently, a more intensive surveillance protocol including whole-body MRI (WB-MRI) has been recommended by International Expert Groups. To address the gap in surveillance for this patient group in the UK, the UK Cancer Genetics Group facilitated a 1-day consensus meeting to discuss a protocol for the UK. Using a preworkshop survey followed by structured discussion on the day, we achieved consensus for a UK surveillance protocol for TP53 carriers to be adopted by UK Clinical Genetics services. The key recommendations are for annual WB-MRI and dedicated brain MRI from birth, annual breast MRI from 20 years in women and three-four monthly abdominal ultrasound in children along with review in a dedicated clinic.

Arterial complications in classical Ehlers-Danlos syndrome: a case series

BACKGROUND

The Ehlers-Danlos syndromes (EDS) are a group of connective tissue disorders with several recognised types. Patients with a type of EDS have connective tissue abnormalities resulting in a varying degree of joint hypermobility, skin and vascular fragility and generalised tissue friability. Classical EDS (cEDS) typically occurs as a result of dominant pathogenic variants in COL5A1 or COL5A2. The cardinal features of cEDS are hyperextensible skin, atrophic scarring and joint hypermobility. Arterial complications are more characteristically a feature of vascular EDS although individual cases of arterial events in cEDS have been reported.

METHODS

A cohort of 154 patients with a clinical diagnosis of cEDS from the UK was analysed.

RESULTS

Seven patients (4.5%) with a diagnosis of cEDS (four pathogenic, one likely pathogenic and two variants of uncertain significance in COL5A1) who had experienced arterial complications were identified. Arterial complications mostly involved medium-sized vessels and also two abdominal aortic aneurysms. No unique clinical features were identified in this group of patients.

CONCLUSION

There is a possible increased risk of arterial complications in patients with cEDS, although not well-defined. Clinicians need to be aware of this possibility when presented with a patient with an arterial complication and features of cEDS. Long-term management in families with cEDS and a vascular complication should be individually tailored to the patient's history and their family's history of vascular events.

Clinical features, molecular results, and management of 12 individuals with the rare arthrochalasia Ehlers-Danlos syndrome

Arthrochalasia Ehlers-Danlos syndrome (aEDS) is a rare autosomal dominant connective tissue disorder that is characterized by congenital bilateral hip dislocations, severe generalized joint hypermobility, recurrent joint (sub)luxations, and skin hyperextensibility. To date, 42 patients with aEDS have been published. We report 12 patients with aEDS from 10 families with 6 unpublished individuals and follow-up data on 6 adult patients. The clinical features are largely comparable with patients reported in the literature. Most (n = 10) patients had variants leading to (partial) loss of exon 6 of the COL1A1 or COL1A2 genes. One patient did not have a previously reported likely pathogenic COL1A1 variant. Data regarding management were retrieved. Hip surgery was performed in 5/12 patients and 3/12 patients underwent spinal surgery. As much as 4/12 patients were wheelchair-bound or unable to walk unaided. Fractures were present in 9/12 individuals with 1 patient requiring bisphosphonate treatment. Echocardiograms were performed in 10 patients and 2 individuals showed an abnormality likely unrelated to aEDS. One patient gave birth to two affected children and went through preterm labor requiring medication but had no additional complications. Of the eight adults in our cohort, the majority entered a career. Our data point toward a genotype-phenotype relationship with individuals with aEDS due to pathogenic COL1A1 variants causing complete or partial loss of exon 6 being more severely affected regarding musculoskeletal features. There is a significant lack of knowledge with regard to management of aEDS, particularly in adulthood. As such, systematic follow-up and multidisciplinary treatment is essential.

Prostate Cancer Risks for Male BRCA1 and BRCA2 Mutation Carriers: A Prospective Cohort Study

BACKGROUND

BRCA1 and BRCA2 mutations have been associated with prostate cancer (PCa) risk but a wide range of risk estimates have been reported that are based on retrospective studies.

OBJECTIVE

To estimate relative and absolute PCa risks associated with BRCA1/2 mutations and to assess risk modification by age, family history, and mutation location.

DESIGN, SETTING, AND PARTICIPANTS

This was a prospective cohort study of male BRCA1 (n = 376) and BRCA2 carriers (n = 447) identified in clinical genetics centres in the UK and Ireland (median follow-up 5.9 and 5.3 yr, respectively).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Standardised incidence/mortality ratios (SIRs/SMRs) relative to population incidences or mortality rates, absolute risks, and hazard ratios (HRs) were estimated using cohort and survival analysis methods.

RESULTS AND LIMITATIONS

Sixteen BRCA1 and 26 BRCA2 carriers were diagnosed with PCa during follow-up. BRCA2 carriers had an SIR of 4.45 (95% confidence interval [CI] 2.99-6.61) and absolute PCa risk of 27% (95% CI 17-41%) and 60% (95% CI 43-78%) by ages 75 and 85 yr, respectively. For BRCA1 carriers, the overall SIR was 2.35 (95% CI 1.43-3.88); the corresponding SIR at age <65 yr was 3.57 (95% CI 1.68-7.58). However, the BRCA1 SIR varied between 0.74 and 2.83 in sensitivity analyses to assess potential screening effects. PCa risk for BRCA2 carriers increased with family history (HR per affected relative 1.68, 95% CI 0.99-2.85). BRCA2 mutations in the region bounded by positions c.2831 and c.6401 were associated with an SIR of 2.46 (95% CI 1.07-5.64) compared to population incidences, corresponding to lower PCa risk (HR 0.37, 95% CI 0.14-0.96) than for mutations outside the region. BRCA2 carriers had a stronger association with Gleason score ≥7 (SIR 5.07, 95% CI 3.20-8.02) than Gleason score ≤6 PCa (SIR 3.03, 95% CI 1.24-7.44), and a higher risk of death from PCa (SMR 3.85, 95% CI 1.44-10.3). Limitations include potential screening effects for these known mutation carriers; however, the BRCA2 results were robust to multiple sensitivity analyses.

CONCLUSIONS

The results substantiate PCa risk patterns indicated by retrospective analyses for BRCA2 carriers, including further evidence of association with aggressive PCa, and give some support for a weaker association in BRCA1 carriers.

PATIENT SUMMARY

In this study we followed unaffected men known to carry mutations in the BRCA1 and BRCA2 genes to investigate whether they are at higher risk of developing prostate cancer compared to the general population. We found that carriers of BRCA2 mutations have a high risk of developing prostate cancer, particularly more aggressive prostate cancer, and that this risk varies by family history of prostate cancer and the location of the mutation within the gene.

Interim Results from the IMPACT Study: Evidence for Prostate-specific Antigen Screening in BRCA2 Mutation Carriers

BACKGROUND

Mutations in BRCA2 cause a higher risk of early-onset aggressive prostate cancer (PrCa). The IMPACT study is evaluating targeted PrCa screening using prostate-specific-antigen (PSA) in men with germline BRCA1/2 mutations.

OBJECTIVE

To report the utility of PSA screening, PrCa incidence, positive predictive value of PSA, biopsy, and tumour characteristics after 3 yr of screening, by BRCA status.

DESIGN, SETTING, AND PARTICIPANTS

Men aged 40-69 yr with a germline pathogenic BRCA1/2 mutation and male controls testing negative for a familial BRCA1/2 mutation were recruited. Participants underwent PSA screening for 3 yr, and if PSA > 3.0 ng/ml, men were offered prostate biopsy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

PSA levels, PrCa incidence, and tumour characteristics were evaluated. Statistical analyses included Poisson regression offset by person-year follow-up, chi-square tests for proportion t tests for means, and Kruskal-Wallis for medians.

RESULTS AND LIMITATIONS

A total of 3027 patients (2932 unique individuals) were recruited (919 BRCA1 carriers, 709 BRCA1 noncarriers, 902 BRCA2 carriers, and 497 BRCA2 noncarriers). After 3 yr of screening, 527 men had PSA > 3.0 ng/ml, 357 biopsies were performed, and 112 PrCa cases were diagnosed (31 BRCA1 carriers, 19 BRCA1 noncarriers, 47 BRCA2 carriers, and 15 BRCA2 noncarriers). Higher compliance with biopsy was observed in BRCA2 carriers compared with noncarriers (73% vs 60%). Cancer incidence rate per 1000 person years was higher in BRCA2 carriers than in noncarriers (19.4 vs 12.0; p =  0.03); BRCA2 carriers were diagnosed at a younger age (61 vs 64 yr; p =  0.04) and were more likely to have clinically significant disease than BRCA2 noncarriers (77% vs 40%; p =  0.01). No differences in age or tumour characteristics were detected between BRCA1 carriers and BRCA1 noncarriers. The 4 kallikrein marker model discriminated better (area under the curve [AUC] = 0.73) for clinically significant cancer at biopsy than PSA alone (AUC = 0.65).

CONCLUSIONS

After 3 yr of screening, compared with noncarriers, BRCA2 mutation carriers were associated with a higher incidence of PrCa, younger age of diagnosis, and clinically significant tumours. Therefore, systematic PSA screening is indicated for men with a BRCA2 mutation. Further follow-up is required to assess the role of screening in BRCA1 mutation carriers.

PATIENT SUMMARY

We demonstrate that after 3 yr of prostate-specific antigen (PSA) testing, we detect more serious prostate cancers in men with BRCA2 mutations than in those without these mutations. We recommend that male BRCA2 carriers are offered systematic PSA screening.

The FANCM:p.Arg658* truncating variant is associated with risk of triple-negative breast cancer

Breast cancer is a common disease partially caused by genetic risk factors. Germline pathogenic variants in DNA repair genes BRCA1, BRCA2, PALB2, ATM, and CHEK2 are associated with breast cancer risk. FANCM, which encodes for a DNA translocase, has been proposed as a breast cancer predisposition gene, with greater effects for the ER-negative and triple-negative breast cancer (TNBC) subtypes. We tested the three recurrent protein-truncating variants FANCM:p.Arg658*, p.Gln1701*, and p.Arg1931* for association with breast cancer risk in 67,112 cases, 53,766 controls, and 26,662 carriers of pathogenic variants of BRCA1 or BRCA2. These three variants were also studied functionally by measuring survival and chromosome fragility in FANCM -/- patient-derived immortalized fibroblasts treated with diepoxybutane or olaparib. We observed that FANCM:p.Arg658* was associated with increased risk of ER-negative disease and TNBC (OR = 2.44, P = 0.034 and OR = 3.79; P = 0.009, respectively). In a country-restricted analysis, we confirmed the associations detected for FANCM:p.Arg658* and found that also FANCM:p.Arg1931* was associated with ER-negative breast cancer risk (OR = 1.96; P = 0.006). The functional results indicated that all three variants were deleterious affecting cell survival and chromosome stability with FANCM:p.Arg658* causing more severe phenotypes. In conclusion, we confirmed that the two rare FANCM deleterious variants p.Arg658* and p.Arg1931* are risk factors for ER-negative and TNBC subtypes. Overall our data suggest that the effect of truncating variants on breast cancer risk may depend on their position in the gene. Cell sensitivity to olaparib exposure, identifies a possible therapeutic option to treat FANCM-associated tumors.

Electron microscopy in the diagnosis of Ehlers-Danlos syndromes: correlation with clinical and genetic investigations

BACKGROUND

The Ehlers-Danlos syndromes (EDS) consist of 13 subtypes with overlapping features including joint hypermobility, skin and vascular fragility and generalized connective tissue friability. As DNA analysis has become the gold standard for investigation of EDS, transmission electron microscopy (TEM) in clinical practice is decreasing. However, owing to the use of next-generation sequencing, the frequency of variants of uncertain significance (VUS) identified using DNA analysis is increasing. We hypothesized that TEM can provide evidence for or against pathogenicity of VUS.

OBJECTIVES

The aim of this study was to evaluate the role of TEM in the diagnosis of EDS subtypes.

METHODS

Data were collected from patients who underwent a skin biopsy between October 2012 and March 2017 at the London EDS National Diagnostic Service. TEM biopsies were categorized as 'normal' or 'abnormal' according to the description and conclusion in the TEM reports. Definitive diagnoses were reached via a combination of clinical features, structural and functional studies and DNA investigations.

RESULTS

The analysis included 177 patients, comprising 30 abnormal and 147 normal TEM reports. A definitive diagnosis of monogenic EDS subtypes was made in 24 patients. Overall, 17 of these 24 patients (71%) had an abnormal biopsy report and seven (29%) had a normal biopsy report. No TEM findings were specifically associated with any EDS subtype, although collagen flowers were present in most patients with a genetically confirmed diagnosis of classical EDS.

CONCLUSIONS

TEM analysis of collagen structure may have the potential to provide evidence for or against the pathogenicity of a VUS, but more work is needed to establish a clear role for TEM in this process. What's already known about this topic? Collagen fibril abnormalities can be seen in several Ehlers-Danlos syndrome (EDS) subtypes. What does this study add? This study provides clinical data, transmission electron microscopy (TEM) data and molecular data of one of the largest groups of patients suspected to have a monogenetic EDS subtype. No TEM findings were specifically associated with an EDS subtype. There was a higher percentage (71%) of abnormal biopsy findings in patients with a definitive diagnosis of a monogenetic EDS subtype and where a class 4/5 genetic variant was present.

Biallelic UFM1 and UFC1 mutations expand the essential role of ufmylation in brain development

The post-translational modification of proteins through the addition of UFM1, also known as ufmylation, plays a critical developmental role as revealed by studies in animal models. The recent finding that biallelic mutations in UBA5 (the E1-like enzyme for ufmylation) cause severe early-onset encephalopathy with progressive microcephaly implicates ufmylation in human brain development. More recently, a homozygous UFM1 variant was proposed as a candidate aetiology of severe early-onset encephalopathy with progressive microcephaly. Here, we establish a locus for severe early-onset encephalopathy with progressive microcephaly based on two families, and map the phenotype to a novel homozygous UFM1 mutation. This mutation has a significantly diminished capacity to form thioester intermediates with UBA5 and with UFC1 (the E2-like enzyme for ufmylation), with resulting impaired ufmylation of cellular proteins. Remarkably, in four additional families where eight children have severe early-onset encephalopathy with progressive microcephaly, we identified two biallelic UFC1 mutations, which impair UFM1-UFC1 intermediate formation with resulting widespread reduction of cellular ufmylation, a pattern similar to that observed with UFM1 mutation. The striking resemblance between UFM1- and UFC1-related clinical phenotype and biochemical derangements strongly argues for an essential role for ufmylation in human brain development. The hypomorphic nature of UFM1 and UFC1 mutations and the conspicuous depletion of biallelic null mutations in the components of this pathway in human genome databases suggest that it is necessary for embryonic survival, which is consistent with the embryonic lethal nature of knockout models for the orthologous genes.

Attitude towards and factors affecting uptake of population-based BRCA testing in the Ashkenazi Jewish population: a cohort study

OBJECTIVE

To evaluate factors affecting unselected population-based BRCA testing in Ashkenazi Jews (AJ).

DESIGN

Cohort-study set within recruitment to the GCaPPS trial (ISRCTN73338115).

SETTING

North London AJ population.

POPULATION OR SAMPLE

Ashkenazi Jews women/men >18 years, recruited through self-referral.

METHODS

Ashkenazi Jews women/men underwent pre-test counselling for BRCA testing through recruitment clinics (clusters). Consenting individuals provided blood samples for BRCA testing. Data were collected on socio-demographic/family history/knowledge/psychological well-being along with benefits/risks/cultural influences (18-item questionnaire measuring 'attitude'). Four-item Likert-scales analysed initial 'interest' and 'intention-to-test' pre-counselling. Uni- and multivariable logistic regression models evaluated factors affecting uptake/interest/intention to undergo BRCA testing. Statistical inference was based on cluster robust standard errors and joint Wald tests for significance. Item-Response Theory and graded-response models modelled responses to 18-item questionnaire.

MAIN OUTCOME MEASURES

Interest, intention, uptake, attitude towards BRCA testing.

RESULTS

A total of 935 individuals (women = 67%/men = 33%; mean age = 53.8 (SD = 15.02) years) underwent pre-test genetic-counselling. During the pre-counselling, 96% expressed interest in and 60% indicated a clear intention to undergo BRCA testing. Subsequently, 88% opted for BRCA testing. BRCA-related knowledge (P = 0.013) and degree-level education (P = 0.01) were positively and negatively (respectively) associated with intention-to-test. Being married/cohabiting had four-fold higher odds for BRCA testing uptake (P = 0.009). Perceived benefits were associated with higher pre-counselling odds for interest in and intention to undergo BRCA testing. Reduced uncertainty/reassurance were the most important factors contributing to decision-making. Increased importance/concern towards risks/limitations (confidentiality/insurance/emotional impact/inability to prevent cancer/marriage ability/ethnic focus/stigmatisation) were significantly associated with lower odds of uptake of BRCA testing, and discriminated between acceptors and decliners. Male gender/degree-level education (P = 0.001) had weaker correlations, whereas having children showed stronger (P = 0.005) associations with attitudes towards BRCA testing.

CONCLUSIONS

BRCA testing in the AJ population has high acceptability. Pre-test counselling increases awareness of disadvantages/limitations of BRCA testing, influencing final cost-benefit perception and decision-making on undergoing testing.

TWEETABLE ABSTRACT

BRCA testing in Ashkenazi Jews has high acceptability and uptake. Pre-test counselling facilitates informed decision-making.

Structural Aberrations with Secondary Implications (SASIs): consensus recommendations for reporting of cancer susceptibility genes identified during analysis of Copy Number Variants (CNVs)

Clinical testing with chromosomal microarray (CMA) is most commonly undertaken for clinical indications such as intellectual disability, dysmorphic features and/or congenital abnormalities. Identification of a structural aberration (SA) involving a cancer susceptibility gene (CSG) constitutes a type of incidental or secondary finding. Laboratory reporting, risk communication and clinical management of these structural aberrations with secondary implications (SASIs) is currently inconsistent. We undertake meta-analysis of 18 622 instances of CMA performed for unrelated indications in which 106 SASIs are identified involving in total 40 different CSGs. Here we present the recommendations of a joint UK working group representing the British Society of Genomic Medicine, UK Cancer Genetics Group and UK Association for Clinical Genomic Science. SASIs are categorised into four groups, defined by the type of SA and the cancer risk. For each group, recommendations are provided regarding reflex parental testing and cancer risk management.

Atypical COL3A1 variants (glutamic acid to lysine) cause vascular Ehlers-Danlos syndrome with a consistent phenotype of tissue fragility and skin hyperextensibility

PURPOSE

The Ehlers-Danlos syndromes (EDS) are a group of rare inherited connective tissue disorders. Vascular EDS (vEDS) is caused by pathogenic variants in COL3A1, most frequently glycine substitutions. We describe the phenotype of the largest series of vEDS patients with glutamic acid to lysine substitutions (Glu>Lys) in COL3A1, which were all previously considered to be variants of unknown significance.

METHODS

Clinical and molecular data for seven families with three different Glu>Lys substitutions in COL3A1 were analyzed.

RESULTS

These Glu>Lys variants were reclassified from variants of unknown significance to either pathogenic or likely pathogenic in accordance with American College of Medical Genetics and Genomics guidelines. All individuals with these atypical variants exhibited skin hyperextensibility as seen in individuals with classical EDS and classical-like EDS and evidence of tissue fragility as seen in individuals with vEDS.

CONCLUSION

The clinical data demonstrate the overlap between the different EDS subtypes and underline the importance of next-generation sequencing gene panel analysis. The three different Glu>Lys variants point toward a new variant type in COL3A1 causative of vEDS, which has consistent clinical features. This is important knowledge for COL3A1 variant interpretation. Further follow-up data are required to establish the severity of tissue fragility complications compared with patients with other recognized molecular causes of vEDS.

Analysis of novel missense ATR mutations reveals new splicing defects underlying Seckel syndrome

Ataxia Telangiectasia and Rad3 related (ATR) is one of the main regulators of the DNA damage response. It coordinates cell cycle checkpoint activation, replication fork stability, restart and origin firing to maintain genome integrity. Mutations of the ATR gene have been reported in Seckel patients, who suffer from a rare genetic disease characterized by severe microcephaly and growth retardation. Here, we report the case of a Seckel patient with compound heterozygous mutations in ATR. One allele has an intronic mutation affecting splicing of neighboring exons, the other an exonic missense mutation, producing the variant p.Lys1665Asn, of unknown pathogenicity. We have modeled this novel missense mutation, as well as a previously described missense mutation p.Met1159Ile, and assessed their effect on ATR function. Interestingly, our data indicate that both missense mutations have no direct effect on protein function, but rather result in defective ATR splicing. These results emphasize the importance of splicing mutations in Seckel Syndrome.

Risks of breast or ovarian cancer in BRCA1 or BRCA2 predictive test negatives: findings from the EMBRACE study

PURPOSE

BRCA1/BRCA2 predictive test negatives are proven noncarriers of a BRCA1/BRCA2 mutation that is carried by their relatives. The risk of developing breast cancer (BC) or epithelial ovarian cancer (EOC) in these women is uncertain. The study aimed to estimate risks of invasive BC and EOC in a large cohort of BRCA1/BRCA2 predictive test negatives.

METHODS

We used cohort analysis to estimate incidences, cumulative risks, and standardized incidence ratios (SIRs).

RESULTS

A total of 1,895 unaffected women were eligible for inclusion in the BC risk analysis and 1,736 in the EOC risk analysis. There were 23 incident invasive BCs and 2 EOCs. The cumulative risk of invasive BC was 9.4% (95% confidence interval (CI) 5.9-15%) by age 85 years and the corresponding risk of EOC was 0.6% (95% CI 0.2-2.6%). The SIR for invasive BC was 0.93 (95% CI 0.62-1.40) in the overall cohort, 0.85 (95% CI 0.48-1.50) in noncarriers from BRCA1 families, and 1.03 (95% CI 0.57-1.87) in noncarriers from BRCA2 families. The SIR for EOC was 0.79 (95% CI 0.20-3.17) in the overall cohort.

CONCLUSION

Our results did not provide evidence for elevated risks of invasive BC or EOC in BRCA1/BRCA2 predictive test negatives.

PEHO syndrome: the endpoint of different genetic epilepsies

Background

Progressive encephalopathy, hypsarrhythmia and optic atrophy (PEHO) has been described as a clinically distinct syndrome. It has been postulated that it is an autosomal recessive condition. However, the aetiology is poorly understood, and the genetic basis of the condition has not been fully elucidated. Our objective was to discover if PEHO syndrome is a single gene disorder.

Method

Children with PEHO and PEHO-like syndrome were recruited. Clinical, neurological and dysmorphic features were recorded; EEG reports and MRI scans were reviewed. Where possible, exome sequencing was carried out first to seek mutations in known early infantile developmental and epileptic encephalopathy (DEE) genes and then to use an agnostic approach to seek novel candidate genes. We sought intra–interfamilial phenotypic correlations and genotype–phenotype correlations when pathological mutations were identified.

Results

Twenty-three children were recruited from a diverse ethnic background, 19 of which were suitable for inclusion. They were similar in many of the core and the supporting features of PEHO, but there was significant variation in MRI and ophthalmological findings, even between siblings with the same mutation. A pathogenic genetic variant was identified in 15 of the 19 children. One further girl’s DNA failed analysis, but her two affected sisters shared confirmed variants. Pathogenic variants were identified in seven different genes.

Conclusions

We found significant clinical and genetic heterogeneity. Given the intrafamily variation demonstrated, we question whether the diagnostic criteria for MRI and ophthalmic findings should be altered. We also question whether PEHO and PEHO-like syndrome represent differing points on a clinical spectrum of the DEE. We conclude that PEHO and PEHO-like syndrome are clinically and genetically diverse entities—and are phenotypic endpoints of many severe genetic encephalopathies.

Consensus for genes to be included on cancer panel tests offered by UK genetics services: guidelines of the UK Cancer Genetics Group

Genetic testing for hereditary cancer predisposition has evolved rapidly in recent years with the discovery of new genes, but there is much debate over the clinical utility of testing genes for which there are currently limited data regarding the degree of associated cancer risk. To address the discrepancies that have arisen in the provision of these tests across the UK, the UK Cancer Genetics Group facilitated a 1-day workshop with representation from the majority of National Health Service (NHS) clinical genetics services. Using a preworkshop survey followed by focused discussion of genes without prior majority agreement for inclusion, we achieved consensus for panels of cancer genes with sufficient evidence for clinical utility, to be adopted by all NHS genetics services. To support consistency in the delivery of these tests and advice given to families across the country, we also developed management proposals for individuals who are found to have pathogenic mutations in these genes. However, we fully acknowledge that the decision regarding what test is most appropriate for an individual family rests with the clinician, and will depend on factors including specific phenotypic features and the family structure.

Prostate-specific antigen velocity in a prospective prostate cancer screening study of men with genetic predisposition

This corrects the article DOI: 10.1038/bjc.2017.429.

Prostate-specific antigen velocity in a prospective prostate cancer screening study of men with genetic predisposition

BACKGROUND

Prostate-specific antigen (PSA) and PSA-velocity (PSAV) have been used to identify men at risk of prostate cancer (PrCa). The IMPACT study is evaluating PSA screening in men with a known genetic predisposition to PrCa due to BRCA1/2 mutations. This analysis evaluates the utility of PSA and PSAV for identifying PrCa and high-grade disease in this cohort.

METHODS

PSAV was calculated using logistic regression to determine if PSA or PSAV predicted the result of prostate biopsy (PB) in men with elevated PSA values. Cox regression was used to determine whether PSA or PSAV predicted PSA elevation in men with low PSAs. Interaction terms were included in the models to determine whether BRCA status influenced the predictiveness of PSA or PSAV.

RESULTS

1634 participants had ⩾3 PSA readings of whom 174 underwent PB and 45 PrCas diagnosed. In men with PSA >3.0 ng ml-l, PSAV was not significantly associated with presence of cancer or high-grade disease. PSAV did not add to PSA for predicting time to an elevated PSA. When comparing BRCA1/2 carriers to non-carriers, we found a significant interaction between BRCA status and last PSA before biopsy (P=0.031) and BRCA2 status and PSAV (P=0.024). However, PSAV was not predictive of biopsy outcome in BRCA2 carriers.

CONCLUSIONS

PSA is more strongly predictive of PrCa in BRCA carriers than non-carriers. We did not find evidence that PSAV aids decision-making for BRCA carriers over absolute PSA value alone.

Diagnosis of lethal or prenatal-onset autosomal recessive disorders by parental exome sequencing

OBJECTIVE

Rare genetic disorders resulting in prenatal or neonatal death are genetically heterogeneous, but testing is often limited by the availability of fetal DNA, leaving couples without a potential prenatal test for future pregnancies. We describe our novel strategy of exome sequencing parental DNA samples to diagnose recessive monogenic disorders in an audit of the first 50 couples referred.

METHOD

Exome sequencing was carried out in a consecutive series of 50 couples who had 1 or more pregnancies affected with a lethal or prenatal-onset disorder. In all cases, there was insufficient DNA for exome sequencing of the affected fetus. Heterozygous rare variants (MAF < 0.001) in the same gene in both parents were selected for analysis. Likely, disease-causing variants were tested in fetal DNA to confirm co-segregation.

RESULTS

Parental exome analysis identified heterozygous pathogenic (or likely pathogenic) variants in 24 different genes in 26/50 couples (52%). Where 2 or more fetuses were affected, a genetic diagnosis was obtained in 18/29 cases (62%). In most cases, the clinical features were typical of the disorder, but in others, they result from a hypomorphic variant or represent the most severe form of a variable phenotypic spectrum.

CONCLUSION

We conclude that exome sequencing of parental samples is a powerful strategy with high clinical utility for the genetic diagnosis of lethal or prenatal-onset recessive disorders. © 2017 The Authors Prenatal Diagnosis published by John Wiley & Sons Ltd.

Phenotypic spectrum associated with de novo mutations in QRICH1 gene

Rare de novo mutations represent a significant cause of idiopathic developmental delay (DD). The use of next-generation sequencing (NGS) has boosted the identification of de novo mutations in an increasing number of novel genes. Here we present 3 unrelated children with de novo loss-of-function (LoF) mutations in QRICH1, diagnosed through trio-based exome sequencing. QRICH1 encodes the glutamine-rich protein 1, which contains 1 caspase activation recruitment domain and is likely to be involved in apoptosis and inflammation. All 3 children had speech delay, learning difficulties, a prominent nose and a thin upper lip. In addition, 2 of them had mildly raised creatine kinase (CK) and 1 of them had autism. Despite their small number, the patients had a relatively consistent pattern of clinical features suggesting the presence of a QRICH1-associated phenotype. LoF mutations in QRICH1 are suggested as a novel cause of DD.

The Ehlers-Danlos syndromes, rare types

The Ehlers-Danlos syndromes comprise a clinically and genetically heterogeneous group of heritable connective tissue disorders, which are characterized by joint hypermobility, skin hyperextensibility, and tissue friability. In the Villefranche Nosology, six subtypes were recognized: The classical, hypermobile, vascular, kyphoscoliotic, arthrochalasis, and dermatosparaxis subtypes of EDS. Except for the hypermobile subtype, defects had been identified in fibrillar collagens or in collagen-modifying enzymes. Since 1997, a whole spectrum of novel, clinically overlapping, rare EDS-variants have been delineated and genetic defects have been identified in an array of other extracellular matrix genes. Advances in molecular testing have made it possible to now identify the causative mutation for many patients presenting these phenotypes. The aim of this literature review is to summarize the current knowledge on the rare EDS subtypes and highlight areas for future research. © 2017 Wiley Periodicals, Inc.

The 2017 international classification of the Ehlers-Danlos syndromes

The Ehlers-Danlos syndromes (EDS) are a clinically and genetically heterogeneous group of heritable connective tissue disorders (HCTDs) characterized by joint hypermobility, skin hyperextensibility, and tissue fragility. Over the past two decades, the Villefranche Nosology, which delineated six subtypes, has been widely used as the standard for clinical diagnosis of EDS. For most of these subtypes, mutations had been identified in collagen-encoding genes, or in genes encoding collagen-modifying enzymes. Since its publication in 1998, a whole spectrum of novel EDS subtypes has been described, and mutations have been identified in an array of novel genes. The International EDS Consortium proposes a revised EDS classification, which recognizes 13 subtypes. For each of the subtypes, we propose a set of clinical criteria that are suggestive for the diagnosis. However, in view of the vast genetic heterogeneity and phenotypic variability of the EDS subtypes, and the clinical overlap between EDS subtypes, but also with other HCTDs, the definite diagnosis of all EDS subtypes, except for the hypermobile type, relies on molecular confirmation with identification of (a) causative genetic variant(s). We also revised the clinical criteria for hypermobile EDS in order to allow for a better distinction from other joint hypermobility disorders. To satisfy research needs, we also propose a pathogenetic scheme, that regroups EDS subtypes for which the causative proteins function within the same pathway. We hope that the revised International EDS Classification will serve as a new standard for the diagnosis of EDS and will provide a framework for future research purposes. © 2017 Wiley Periodicals, Inc.

A cohort of 17 patients with kyphoscoliotic Ehlers-Danlos syndrome caused by biallelic mutations in FKBP14: expansion of the clinical and mutational spectrum and description of the natural history

Purpose

In 2012 we reported in six individuals a clinical condition almost indistinguishable from PLOD1-kyphoscoliotic Ehlers–Danlos syndrome (PLOD1-kEDS), caused by biallelic mutations in FKBP14, and characterized by progressive kyphoscoliosis, myopathy, and hearing loss in addition to connective tissue abnormalities such as joint hypermobility and hyperelastic skin. FKBP14 is an ER-resident protein belonging to the family of FK506-binding peptidyl-prolyl cis–trans isomerases (PPIases); it catalyzes the folding of type III collagen and interacts with type III, type VI, and type X collagens. Only nine affected individuals have been reported to date.

Methods

We report on a cohort of 17 individuals with FKBP14-kEDS and the follow-up of three previously reported patients, and provide an extensive overview of the disorder and its natural history based on clinical, biochemical, and molecular genetics data.

Results

Based on the frequency of the clinical features of 23 patients from the present and previous cohorts, we define major and minor features of FKBP14-kEDS. We show that myopathy is confirmed by histology and muscle imaging only in some patients, and that hearing impairment is predominantly sensorineural and may not be present in all individuals.

Conclusion

Our data further support the extensive clinical overlap with PLOD1-kEDS and show that vascular complications are rare manifestations of FKBP14-kEDS.

Somatic mutations and progressive monosomy modify SAMD9-related phenotypes in humans

It is well established that somatic genomic changes can influence phenotypes in cancer, but the role of adaptive changes in developmental disorders is less well understood. Here we have used next-generation sequencing approaches to identify de novo heterozygous mutations in sterile α motif domain-containing protein 9 (SAMD9, located on chromosome 7q21.2) in 8 children with a multisystem disorder termed MIRAGE syndrome that is characterized by intrauterine growth restriction (IUGR) with gonadal, adrenal, and bone marrow failure, predisposition to infections, and high mortality. These mutations result in gain of function of the growth repressor product SAMD9. Progressive loss of mutated SAMD9 through the development of monosomy 7 (-7), deletions of 7q (7q-), and secondary somatic loss-of-function (nonsense and frameshift) mutations in SAMD9 rescued the growth-restricting effects of mutant SAMD9 proteins in bone marrow and was associated with increased length of survival. However, 2 patients with -7 and 7q- developed myelodysplastic syndrome, most likely due to haploinsufficiency of related 7q21.2 genes. Taken together, these findings provide strong evidence that progressive somatic changes can occur in specific tissues and can subsequently modify disease phenotype and influence survival. Such tissue-specific adaptability may be a more common mechanism modifying the expression of human genetic conditions than is currently recognized.

A Recurrent Mosaic Mutation in SMO, Encoding the Hedgehog Signal Transducer Smoothened, Is the Major Cause of Curry-Jones Syndrome

Curry-Jones syndrome (CJS) is a multisystem disorder characterized by patchy skin lesions, polysyndactyly, diverse cerebral malformations, unicoronal craniosynostosis, iris colobomas, microphthalmia, and intestinal malrotation with myofibromas or hamartomas. Cerebellar medulloblastoma has been described in a single affected individual; in another, biopsy of skin lesions showed features of trichoblastoma. The combination of asymmetric clinical features, patchy skin manifestations, and neoplastic association previously led to the suggestion that this could be a mosaic condition, possibly involving hedgehog (Hh) signaling. Here, we show that CJS is caused by recurrent somatic mosaicism for a nonsynonymous variant in SMO (c.1234C>T [p.Leu412Phe]), encoding smoothened (SMO), a G-protein-coupled receptor that transduces Hh signaling. We identified eight mutation-positive individuals (two of whom had not been reported previously) with highly similar phenotypes and demonstrated varying amounts of the mutant allele in different tissues. We present detailed findings from brain MRI in three mutation-positive individuals. Somatic SMO mutations that result in constitutive activation have been described in several tumors, including medulloblastoma, ameloblastoma, and basal cell carcinoma. Strikingly, the most common of these mutations is the identical nonsynonymous variant encoding p.Leu412Phe. Furthermore, this substitution has been shown to activate SMO in the absence of Hh signaling, providing an explanation for tumor development in CJS. This raises therapeutic possibilities for using recently generated Hh-pathway inhibitors. In summary, our work uncovers the major genetic cause of CJS and illustrates strategies for gene discovery in the context of low-level tissue-specific somatic mosaicism.

CCDC88A mutations cause PEHO-like syndrome in humans and mouse

Progressive encephalopathy with oedema, hypsarrhythmia and optic atrophy (PEHO) syndrome is a rare Mendelian phenotype comprising severe retardation, early onset epileptic seizures, optic nerve/cerebellar atrophy, pedal oedema, and early death. Atypical cases are often known as PEHO-like, and there is an overlap with 'early infantile epileptic encephalopathy'. PEHO is considered to be recessive, but surprisingly since initial description in 1991, no causative recessive gene(s) have been described. Hence, we report a multiplex consanguineous family with the PEHO phenotype where affected individuals had a homozygous frame-shift deletion in CCDC88A (c.2313delT, p.Leu772*ter). Analysis of cDNA extracted from patient lymphocytes unexpectedly failed to show non-sense mediated decay, and we demonstrate that the mutation produces a truncated protein lacking the crucial C-terminal half of CCDC88A (girdin). To further investigate the possible role of CCDC88A in human neurodevelopment we re-examined the behaviour and neuroanatomy of Ccdc88a knockout pups. These mice had mesial-temporal lobe epilepsy, microcephaly and corpus callosum deficiency, and by postnatal Day 21, microcephaly; the mice died at an early age. As the mouse knockout phenotype mimics the human PEHO phenotype this suggests that loss of CCDC88A is a cause of the PEHO phenotype, and that CCDC88A is essential for multiple aspects of normal human neurodevelopment.

The Angelina Jolie effect: how high celebrity profile can have a major impact on provision of cancer related services

Introduction

It is frequent for news items to lead to a short lived temporary increase in interest in a particular health related service, however it is rare for this to have a long lasting effect. In 2013, in the UK in particular, there has been unprecedented publicity in hereditary breast cancer, with Angelina Jolie’s decision to have genetic testing for the BRCA1 gene and subsequently undergo risk reducing mastectomy (RRM), and a pre-release of the NICE guidelines on familial breast cancer in January and their final release on 26^th June. The release of NICE guidelines created a lot of publicity over the potential for use of chemoprevention using tamoxifen or raloxifene. However, the longest lasting news story was the release of details of film actress Angelina Jolie’s genetic test and surgery.

Methods

To assess the potential effects of the ‘Angelina Jolie’ effect, referral data specific to breast cancer family history was obtained from around the UK for the years 2012 and 2013. A consortium of over 30 breast cancer family history clinics that have contributed to two research studies on early breast surveillance were asked to participate as well as 10 genetics centres. Monthly referrals to each service were collated and increases from 2012 to 2013 assessed.

Results

Data from 12 family history clinics and 9 regional genetics services showed a rise in referrals from May 2013 onwards. Referrals were nearly 2.5 fold in June and July 2013 from 1,981 (2012) to 4,847 (2013) and remained at around two-fold to October 2013. Demand for BRCA1/2 testing almost doubled and there were also many more enquiries for risk reducing mastectomy. Internal review shows that there was no increase in inappropriate referrals.

Conclusions

The Angelina Jolie effect has been long lasting and global, and appears to have increased referrals to centres appropriately.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-014-0442-6) contains supplementary material, which is available to authorized users.

Targeted prostate cancer screening in BRCA1 and BRCA2 mutation carriers: results from the initial screening round of the IMPACT study

BACKGROUND

Men with germline breast cancer 1, early onset (BRCA1) or breast cancer 2, early onset (BRCA2) gene mutations have a higher risk of developing prostate cancer (PCa) than noncarriers. IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls) is an international consortium of 62 centres in 20 countries evaluating the use of targeted PCa screening in men with BRCA1/2 mutations.

OBJECTIVE

To report the first year's screening results for all men at enrollment in the study.

DESIGN, SETTING AND PARTICIPANTS

We recruited men aged 40-69 yr with germline BRCA1/2 mutations and a control group of men who have tested negative for a pathogenic BRCA1 or BRCA2 mutation known to be present in their families. All men underwent prostate-specific antigen (PSA) testing at enrollment, and those men with PSA >3 ng/ml were offered prostate biopsy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

PSA levels, PCa incidence, and tumour characteristics were evaluated. The Fisher exact test was used to compare the number of PCa cases among groups and the differences among disease types.

RESULTS AND LIMITATIONS

We recruited 2481 men (791 BRCA1 carriers, 531 BRCA1 controls; 731 BRCA2 carriers, 428 BRCA2 controls). A total of 199 men (8%) presented with PSA >3.0 ng/ml, 162 biopsies were performed, and 59 PCas were diagnosed (18 BRCA1 carriers, 10 BRCA1 controls; 24 BRCA2 carriers, 7 BRCA2 controls); 66% of the tumours were classified as intermediate- or high-risk disease. The positive predictive value (PPV) for biopsy using a PSA threshold of 3.0 ng/ml in BRCA2 mutation carriers was 48%-double the PPV reported in population screening studies. A significant difference in detecting intermediate- or high-risk disease was observed in BRCA2 carriers. Ninety-five percent of the men were white, thus the results cannot be generalised to all ethnic groups.

CONCLUSIONS

The IMPACT screening network will be useful for targeted PCa screening studies in men with germline genetic risk variants as they are discovered. These preliminary results support the use of targeted PSA screening based on BRCA genotype and show that this screening yields a high proportion of aggressive disease.

PATIENT SUMMARY

In this report, we demonstrate that germline genetic markers can be used to identify men at higher risk of prostate cancer. Targeting screening at these men resulted in the identification of tumours that were more likely to require treatment.

Genetic heterogeneity in Cornelia de Lange syndrome (CdLS) and CdLS-like phenotypes with observed and predicted levels of mosaicism

BACKGROUND

Cornelia de Lange syndrome (CdLS) is a multisystem disorder with distinctive facial appearance, intellectual disability and growth failure as prominent features. Most individuals with typical CdLS have de novo heterozygous loss-of-function mutations in NIPBL with mosaic individuals representing a significant proportion. Mutations in other cohesin components, SMC1A, SMC3, HDAC8 and RAD21 cause less typical CdLS.

METHODS

We screened 163 affected individuals for coding region mutations in the known genes, 90 for genomic rearrangements, 19 for deep intronic variants in NIPBL and 5 had whole-exome sequencing.

RESULTS

Pathogenic mutations [including mosaic changes] were identified in: NIPBL 46 [3] (28.2%); SMC1A 5 [1] (3.1%); SMC3 5 [1] (3.1%); HDAC8 6 [0] (3.6%) and RAD21 1 [0] (0.6%). One individual had a de novo 1.3 Mb deletion of 1p36.3. Another had a 520 kb duplication of 12q13.13 encompassing ESPL1, encoding separase, an enzyme that cleaves the cohesin ring. Three de novo mutations were identified in ANKRD11 demonstrating a phenotypic overlap with KBG syndrome. To estimate the number of undetected mosaic cases we used recursive partitioning to identify discriminating features in the NIPBL-positive subgroup. Filtering of the mutation-negative group on these features classified at least 18% as 'NIPBL-like'. A computer composition of the average face of this NIPBL-like subgroup was also more typical in appearance than that of all others in the mutation-negative group supporting the existence of undetected mosaic cases.

CONCLUSIONS

Future diagnostic testing in 'mutation-negative' CdLS thus merits deeper sequencing of multiple DNA samples derived from different tissues.

Microcephaly with or without chorioretinopathy, lymphoedema, or mental retardation (MCLMR): review of phenotype associated with KIF11 mutations

Microcephaly with or without chorioretinopathy, lymphoedema, or mental retardation (MCLMR) (MIM No.152950) is a rare autosomal dominant condition for which a causative gene has recently been identified. Mutations in the kinesin family member 11 (KIF11) gene have now been described in 16 families worldwide. This is a review of the condition based on the clinical features of 37 individuals from 22 families. This report includes nine previously unreported families and additional information for some of those reported previously. The condition arose de novo in 8/20 families (40%). The parental results were not available for two probands. The mutations were varied and include missense, nonsense, frameshift, and splice site and are distributed evenly throughout the KIF11 gene. In our cohort, 86% had microcephaly, 78% had an ocular abnormality consistent with the diagnosis, 46% had lymphoedema, 73% had mild-moderate learning difficulties, 8% had epilepsy, and 8% had a cardiac anomaly. We identified three individuals with KIF11 mutations but no clinical features of MCLMR demonstrating reduced penetrance. The variable expression of the phenotype and the presence of mildly affected individuals indicates that the prevalence may be higher than expected, and we would therefore recommend a low threshold for genetic testing.