Identification and Management of Pathogenic Variants in BRCA1, BRCA2, and PALB2 in a Tumor-Only Genomic Testing Program

PURPOSE

Tumor-only genomic testing can uncover somatic and germline pathogenic variants (P/LPs) in cancer predisposition genes. We describe the prevalence of P/LPs in BRCA1/2 and PALB2 (B1B2P2) across malignancies and the frequency of clinical germline testing (CGT) in patients with P/LPs in B1B2P2 identified on tumor-only testing.

EXPERIMENTAL DESIGN

Among 7,575 patients tested between 2016-2018 with the OncoPanel tumor-only sequencing assay, we characterized P/LP frequencies by tumor type, receipt of CGT prior to or within 12 months (m) after OncoPanel, and factors associated with CGT.

RESULTS

272 (3.6%) had OncoPanel-detected P/LPs in B1B2P2: 37.5% of P/LPs were in BRCA-related cancers; the remainder were in non-BRCA tumors. P/LPs were detected in {greater than or equal to}5% of breast, pancreatic, prostate, ovarian, non-melanoma skin, endometrial, small-cell lung and colorectal cancers. 37.9% of patients with P/LPs received GCT prior to OncoPanel; an additional 10.7% underwent CGT within 12m of OncoPanel. Among 132 with CGT, 88.6% had {greater than or equal to}1 clinical factor for CGT compared to 47.1% who did not undergo CGT. Patients with BRCA-tumors were more likely to have CGT compared to those without (81.4% vs. 29.0%, p<0.0001). Among patients with CGT, 70.5% (93/132) of P/LPs were germline.

CONCLUSION

Tumor-only genomic testing identified P/LPs in B1B2P2 in 3.6% of patients. 52.9% of patients with tumor-detected P/LPs and without CGT did not meet personal or family history criteria for CGT. Additionally, some patients with tumor-detected P/LPs were not referred for CGT, especially those with non-BRCA tumors. Given implications for treatment selection and familial cancer risk, processes to reliably trigger CGT from tumor-genomic findings are needed.

Newborn Screening for the Detection of the TP53 R337H Variant and Surveillance for Early Diagnosis of Pediatric Adrenocortical Tumors: Lessons Learned and Way Forward

Simple Summary

Adrenocortical tumor (ACT) is rare in children and fatal if not detected early. Children who inherit a mutation of the TP53 gene tend to develop ACT early in life. In the 1990s, scientists revealed that a TP53 variant (R337H) was frequent in South Brazil. Therefore, the incidence of ACT in children is 20 times higher in this region than in other countries. We reviewed the records of 16 children with ACT treated in a pediatric hospital in Parana state (southern Brazil) and 134 children registered in the state public registry data. We found a high number of cases with advanced disease, leading to an unacceptable number of deaths. These observations contradict newborn R337H screening and surveillance data, showing that surgical intervention in early cases of ACT is associated with a 100% cure. Newborn screening/surveillance should be implemented in regions with a high frequency of the R337H variant.

Abstract

The incidence of pediatric adrenocortical tumors (ACT) is high in southern Brazil due to the founder TP53 R337H variant. Neonatal screening/surveillance (NSS) for this variant resulted in early ACT detection and improved outcomes. The medical records of children with ACT who did not participate in newborn screening (non-NSS) were reviewed (2012–2018). We compared known prognostic factors between the NSS and non-NSS cohorts and estimated surveillance and treatment costs. Of the 16 non-NSS children with ACT carrying the R337H variant, the disease stages I, II, III, and IV were observed in five, five, one, and five children, respectively. The tumor weight ranged from 22 to 608 g. The 11 NSS children with ACT all had disease stage I and were alive. The median tumor weight, age of diagnosis, and interval between symptoms and diagnosis were 21 g, 1.9 years, and two weeks, respectively, for the NSS cohort and 210 g, 5.2 years, and 15 weeks, respectively, for the non-NSS cohort. The estimated surveillance/screening cost per year of life saved is US$623/patient. NSS is critical for improving the outcome of pediatric ACT in this region. Hence, we strongly advocate for the inclusion of R337H in the state-mandated universal screening and surveillance.

Germline Testing Data Validate Inferences of Mutational Status for Variants Detected From Tumor-Only Sequencing

Pathogenic germline variants (PGVs) in cancer susceptibility genes are usually identified through germline testing of DNA from blood or saliva: their detection can affect treatment options and potential risk-reduction strategies for patient relatives. PGV can also be identified in tumor sequencing assays, which, when performed without patient-matched normal specimens, render determination of variants' germline or somatic origin critical.

Germline testing data from 1,600 cancer patients validate information-theoretic, gene-independent inference of germline vs. somatic status for variants detected by clinical tumor-only sequencing.

Identification and management of pathogenic mutations in BRCA1, BRCA2, and PALB2 in a tumor-only genomic testing program

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Background: Tumor-genomic testing is increasingly used to guide treatment decisions in cancer patients. Although tumor-only testing cannot definitively distinguish between germline versus somatic alterations, the identification of pathogenic or likely pathogenic (P/LP) variants in certain genes should prompt consideration of germline testing. Germline P/LPs in BRCA1, BRCA2 and PALB2 ( B1B2PAL) are associated with hereditary cancer syndromes. Methods: We reviewed tumor-only genomic data (Dana-Farber Oncopanel) between 10/2016 and 6/2018 to examine the prevalence of P/LPs in BRCA1, BRCA2, PALB2 among adult cancer patients at Dana-Farber Cancer Institute/Brigham and Women’s Hospital. We characterized the frequency of P/LPs by primary tumor type, confirmation by germline testing before or within 12 months after Oncopanel testing or not, and factors associated with germline testing. Results: Among 7,575 patients, the median age was 62 (range 18-99); 53.9% were female. A total of 272 (3.6%) had P/LPs in BRCA1 (n = 90), BRCA2 (n = 162) and/or PALB2 (n = 29). P/LPs in B1B2PAL were detected in 5.3% (38/712) of breast, 11.9% (34/285) of ovarian, 6.6% (18/272) of pancreatic, and 5.1% (12/234) of prostate cancers. P/LPs in B1B2PAL were also detected in other neoplasms (12.9% (8/62) of non-melanoma skin, 5.0% (43/855) of colorectal, 7.6% (20/264) of endometrial, and 4.6% (10/216) of head and neck cancers). Of 169 patients who had not had prior germline testing, 29/169 (17.2%) completed germline testing within 12 months after Oncopanel; 13 (7.7%) referred for testing declined or did not complete testing within 12 months, 14 (8.3%) died before or within 3 months of the Oncopanel results, and 113 (66.9%) had no documented germline testing within 12 months. Among 132 patients who had germline testing, 117 (88.6%) had a clinical indication based on personal or family history compared to 66/140 (47.1%) who did not undergo germline testing. Among 132/272 (48.5%) germline-tested patients, 70.5% were positive for a germline mutation in B1B2PAL; the remainder had somatic B1B2PAL mutations only. Germline testing was more often performed in patients with B1B2PAL-associated tumors (breast, ovarian, pancreatic and prostate cancers) or other clinical indications for germline testing. Conclusions: A low but clinically meaningful rate of P/LPs in BRCA1, BRCA2 and PALB2 was detected by tumor-only genomic testing in diverse malignancies. Given the implications of B1B2PAL alterations on treatment and familial cancer risk, our data support current NCCN guidelines recommending germline testing among patients with cancer and P/LPs in B1B2PAL detected on tumor-genomic testing and highlights the need for systems to ensure germline testing when indicated.

Clinical and molecular evaluation of 13 Brazilian patients with Gomez-López-Hernández syndrome

We aim to characterize patients with Gomez-López-Hernández syndrome (GLHS) clinically and to investigate them molecularly. A clinical protocol, including a morphological and neuropsychological assessment, was applied to 13 patients with GLHS. Single-nucleotide polymorphism (SNP) array and whole-exome sequencing were undertaken; magnetic resonance imaging was performed in 12 patients, including high-resolution, heavily T2-weighted sequences (HRT2) in 6 patients to analyze the trigeminal nerves. All patients presented alopecia; two did not present rhombencephalosynapsis (RES); trigeminal anesthesia was present in 5 of the 11 patients (45.4%); brachycephaly/brachyturricephaly and mid-face retrusion were found in 84.6 and 92.3% of the patients, respectively. One patient had intellectual disability. HRT2 sequences showed trigeminal nerve hypoplasia in four of the six patients; all four had clinical signs of trigeminal anesthesia. No common candidate gene was found to explain GLHS phenotype. RES does not seem to be an obligatory finding in respect of GLHS diagnosis. We propose that a diagnosis of GLHS should be considered in patients with at least two of the following criteria: focal non-scarring alopecia, rhombencephalosynapsis, craniofacial anomalies (brachyturrycephaly, brachycephaly or mid-face retrusion), trigeminal anesthesia or anatomic abnormalities of the trigeminal nerve. Studies focusing on germline whole genome sequencing or DNA and/or RNA sequencing of the alopecia tissue may be the next step for the better understanding of GLHS etiology.

Abstract LB-245: Validating models of imputing germline versus somatic status for variants detected by tumor-only genomic profiling using germline clinical testing data

The goal of tumor genomic profiling is to identify somatic mutations. However, most implementations lack patient-matched control DNA sequence to enable determination of variant source (somatic or germline) and resolution of allelic status, including possible loss of heterozygosity (LOH), without additional analyses based on accurate estimates of specimens' tumor purity. Here, we present the validation of an information-theoretic algorithm for identifying germline variants detected in tumor-only sequencing using cancer patient clinical germline test data. 1,631 adult patients consented for the PROFILE study at DFCI between 2014 and 2018, and also underwent clinical germline testing. DNA was isolated from tissue containing >20% tumor nuclei and analyzed using Agilent SureSelect hybrid capture kit. All exons and 191 introns in 447 genes were interrogated for single nucleotide variants, small indels, copy number alterations, and structural variants using standard pipelines. Germline testing was performed at CLIA-certified laboratories. Specimen tumor purity was estimated using computational approaches developed at DFCI and Rutgers with further manual curation. LOHGIC (LOH-Germline Inference Calculator), developed on a model-selection scheme using Akaike Information Criterion weighting, was applied to individual variants to infer the most consistent germline-v-somatic model and LOH status, incorporating biases in clinical sequencing and purity estimation. 427 patients had 676 variants detected in high-penetrance cancer predisposition genes: BRCA1, BRCA2, MLH1, MSH2, MSH6 and PMS2. Comparison of LOHGIC's results with germline test data showed 91.4% accuracy, 67.6% precision, and 67.0% recall, with other performance measures reported in Table 1. LOHGIC showed evidence of LOH for 35% of variants with concordant inference and germline testing results. Special challenges with TP53 variants will also be discussed. Our results indicate that tumor-only sequencing can provide excellent power for statistical approaches to identify likely germline mutations and infer LOH. Our analyses may be confounded by the presence of reversion mutations, poor specimen quality, inaccurate purity estimates, low sequencing depths, and/or germline call variability. This work further demonstrates the need for a systematic effort to interpret clinical-grade sequencing results.

Table 1.Summary of resultsGeneBRCA1BRCA2MLH1MSH2MSH6PMS2OverallGermline Test: Positive/Negative28/10445/1753/6010/6514/12112/39112/564Germline Inference: Positive/Negative/Ambiguous24/94/1448/138/347/46/1013/51/1115/105/154/37/10111/471/94Positive Predictive Value (PPV)79.270.842.969.246.775.067.6Negative Predictive Value (NPV)95.798.6100.0100.096.286.596.9True Positive Rate (TPR)67.975.6100.090.050.025.067.0False Omission Rate (FOR)4.31.40.00.03.813.53.1Sensitivity82.694.4100.0100.063.637.583.3Specificity94.790.792.092.792.797.092.8Accuracy92.491.492.593.890.085.491.4

Citation Format: Israel Gomy, Nahed Jalloul, Samantha Stokes, Alexander Gusev, Shridar Ganesan, Judy Garber, Hossein Khiabanian. Validating models of imputing germline versus somatic status for variants detected by tumor-only genomic profiling using germline clinical testing data [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-245.

Hereditary cancer risk assessment: insights and perspectives for the Next-Generation Sequencing era

Hereditary cancer risk assessment is a multidisciplinary and dynamic process, with the purpose of estimating probabilities of germline mutations in cancer susceptibility genes and assessing empiric risks of cancer based on personal and family histories, in order to offer clinical and molecular diagnoses and clinical management based on these risks. Genetic tests are available and most of them are reimbursed by insurance companies, although they are generally not covered by the public health systems of developing countries. More recently, molecular diagnosis of hereditary cancer is feasible through next-generation sequencing (NGS) panels. Here we review the benefits and limitations of NGS technologies in the clinical practice.

Contribution of rare germline copy number variations and common susceptibility loci in Lynch syndrome patients negative for mutations in the mismatch repair genes

In colorectal carcinoma (CRC), 35% of cases are known to have a hereditary component, while a lower proportion (∼ 5%) can be explained by known genetic factors. In this study, copy number variations (CNVs) were evaluated in 45 unrelated patients with clinical hypothesis of Lynch syndrome (Amsterdam or Bethesda criteria); negative for MLH1, MSH2, MSH6, PMS2, CHEK2*1100delC and TP53 pathogenic mutations; aiming to reveal new predisposing genes. Analyses with two different microarray platforms (Agilent 180K and Affymetrix CytoScan HD) revealed 35 rare CNVs covering 67 known genes in 22 patients. Gains (GALNT6 and GALNT11) and losses (SEMA3C) involving the same gene families related to CRC susceptibility were found among the rare CNVs. Segregation analysis performed on four relatives from one family suggested the involvement of GALNT11 and KMT2C in those at risk of developing CRC. Notably, in silico molecular analysis revealed that 61% (41/67) of the genes covered by rare CNVs were associated with cancer, mainly colorectal (17 genes). Ten common SNPs, previously associated with CRC, were genotyped in 39 index patients and 100 sporadic CRC cases. Although no significant, an increased number of risk alleles was detected in the index cases compared with the sporadic CRC patients. None of the SNPs were covered by CNVs, suggesting an independent effect of each alteration in cancer susceptibility. In conclusion, rare germline CNVs and common SNPs may contribute to an increased risk for hereditary CRC in patients with mismatch repair proficiency.

Hereditary cancer risk assessment: essential tools for a better approach

Hereditary cancer risk assessment (HCRA) is a multidisciplinary process of estimating probabilities of germline mutations in cancer susceptibility genes and assessing empiric risks of cancer, based on personal and family history. It includes genetic counseling, testing and management of at-risk individuals so that they can make well-informed choices about cancer surveillance, surgical treatment and chemopreventive measures, including biomolecular cancer therapies. Providing patients and family members with an appropriate HCRA will contribute to a better process of making decisions about their personal and family risks of cancer. Following individuals at high risk through screening protocols, reassuring those at low risk, and referring those at increased risk of hereditary cancer to a cancer genetics center may be the best suitable approach of HCRA.

Colorectal cancer inherited susceptibility: The first replication study in the Brazilian population

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Background: Inherited susceptibility to colorectal cancer (CRC) is known since twin studies have revealed 35% of heritability. Genome-wide association studies (GWAS) have uncovered less than a half of this proportion through genotyping tagSNPs of individuals with European ancestry. To date only 20 common SNPs have achieved genome-wide significance and replication studies from non-European populations are scarce. Here we show preliminary data of the first study of CRC inherited susceptibility in the Brazilian population and aimed to replicate European studies. Methods: We genotyped 1,395 individuals (675 cases and 720 controls) for 10 tagSNPs (rs6983267, rs4939827, rs4779584, rs16892766, rs10795668, rs4444235, rs9929218, rs10411210, rs961253, rs3802842) using TaqMan SNP Genotyping Assays and SDS2.3 software (Applied Biosystems). We exclude from the analysis SNPs with significant deviation from Hardy-Weinberg equilibrium. Results: Significant association was found between six out of ten SNPs and CRC risk for most genetic models. One SNP (rs10411210) was associated with a low risk of CRC. Conclusions: Despite we did not analyze population stratification, this study partially replicate European GWAS in an admixed population. Therefore, it is worth to explore other ethnic backgrounds that would ultimately help to uncover the missing heritability of CRC and narrow the boundaries of the genetic architecture of CRC susceptibility. [Table: see text]

Evaluation of MLH1 I219V polymorphism in unrelated South American individuals suspected of having Lynch syndrome

BACKGROUND

Some single-nucleotide polymorphisms are associated with higher risk of colorectal cancer development and are suggested to explain part of the genetic contribution to Lynch syndrome.

AIM

To evaluate the mutL homolog 1 (MLH1) I219V polymorphism in 124 unrelated South American individuals suspected of having Lynch syndrome, based on frequency, association with pathogenic MLH1 and mutS homolog 2 (MSH2) mutation and clinical features.

MATERIALS AND METHODS

DNA was obtained from peripheral blood and polymerase chain reaction (PCR) was performed, followed by direct sequencing.

RESULTS

The Val allelic of the I219V polymorphism was found in 51.61% (64/124) of the individuals, with an allelic frequency of 0.3. MLH1 or MHS2 pathogenic mutations were found in 32.81% (21/64) and in 23.33% (14/60) of Val-carriers and non-carriers, respectively.

CONCLUSION

The Val-carrying genotype was frequent in the studied population; however, it does not appear to exert any modifier effect on MLH1 or MSH2 pathogenic mutations and the development of colorectal cancer.

A clinical follow-up of 35 Brazilian patients with Prader-Willi syndrome

OBJECTIVE

Prader-Willi Syndrome is a common etiology of syndromic obesity that is typically caused by either a paternal microdeletion of a region in chromosome 15 (microdeletions) or a maternal uniparental disomy of this chromosome. The purpose of this study was to describe the most significant clinical features of 35 Brazilian patients with molecularly confirmed Prader-Willi syndrome and to determine the effects of growth hormone treatment on clinical outcomes.

METHODS

A retrospective study was performed based on the medical records of a cohort of 35 patients diagnosed with Prader-Willi syndrome. The main clinical characteristics were compared between the group of patients presenting with microdeletions and the group presenting with maternal uniparental disomy of chromosome 15. Curves for height/length, weight and body mass index were constructed and compared between Prader-Willi syndrome patients treated with and without growth hormone to determine how growth hormone treatment affected body composition. The curves for these patient groups were also compared with curves for the normal population.

RESULTS

No significant differences were identified between patients with microdeletions and patients with maternal uniparental disomy for any of the clinical parameters measured. Growth hormone treatment considerably improved the control of weight gain and body mass index for female patients but had no effect on either parameter in male patients. Growth hormone treatment did not affect height/length in either gender.

CONCLUSION

The prevalence rates of several clinical features in this study are in agreement with the rates reported in the literature. Additionally, we found modest benefits of growth hormone treatment but failed to demonstrate differences between patients with microdeletions and those with maternal uniparental disomy. The control of weight gain in patients with Prader-Willi syndrome is complex and does not depend exclusively on growth hormone treatment.

Abstract 2108: Prevalence of mutations in MSH6, PMS1 and PMS2 gene in Brazilian families with Lynch syndrome

Background: Lynch syndrome (LS) is an autosomal dominant disorder predisposing to colorectal cancer and increased risk for cancers of the stomach, small intestine, hepatobiliary system, kidney, ureter, ovary, and sebaceous tumors. Germline mutations in the MMR genes MutL homolog 1 (MLH1), MutS homolog 2 (MSH2), MutS homolog 6 (MSH6), post- meiotic segregation increased 1 (PMS1) or post- meiotic segregation increased 2 (PMS2), are known to cause LS. While mutations in MLH1 and MSH2 gene, account for 70% - 80% of all Lynch syndrome colorectal cancers, the involvement of the MSH6, PMS2 and PMS1 gene is continually rising. Altogether, MSH6, PMS1 and PMS2 mutations account for 5-20% of kindreds in which MSH2 and MLH1 mutations are excluded. Objective: The aim of the study was evaluate the frequency of mutations in MSH6, PMS1 and PMS2 gene. Methods: Seventy one unrelated patients without MLH1/MSH2 mutations were eligible for this study. Genomic DNA was obtained from peripheral blood and primers were designed within introns of all exons of MSH6, PMS1 gene. In order to avoid the amplification of pseudogenes for the PMS2 gene, a set of four primer pairs were design. Results: Out of 71 patients, 20 fulfilled the Amsterdam criteria and other 51 fulfilled the Bethesda guideline. Four novel pathogenic mutations were detected, three in MSH6 and 1 in PMS2. In addition, 7 variants of uncertain significance were encountered, in which two of them were previously described as pathogenic. No mutations were found in PMS1 gene. Conclusion: Our data shows that 8.5% (6/71) of the individuals have mutations in MSH6 and PMS2 gene and these results strongly suggest that MSH6 and PMS2 should not be excluded from the MMR screening in Brazilian families suspected for Lynch syndrome.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2108. doi:1538-7445.AM2012-2108

Characterization of germline mutations of MLH1 and MSH2 in unrelated south American suspected Lynch syndrome individuals

Lynch syndrome (LS) is an autosomal dominant syndrome that predisposes individuals to development of cancers early in life. These cancers are mainly the following: colorectal, endometrial, ovarian, small intestine, stomach and urinary tract cancers. LS is caused by germline mutations in DNA mismatch repair genes (MMR), mostly MLH1 and MSH2, which are responsible for more than 85% of known germline mutations. To search for germline mutations in MLH1 and MSH2 genes in 123 unrelated South American suspected LS patients (Bethesda or Amsterdam Criteria) DNA was obtained from peripheral blood, and PCR was performed followed by direct sequencing in both directions of all exons and intron-exon junctions regions of the MLH1 and MSH2 genes. MLH1 or MSH2 pathogenic mutations were found in 28.45% (34/123) of the individuals, where 25/57 (43.85%) fulfilled Amsterdam I, II and 9/66 (13.63%) the Bethesda criteria. The mutations found in both genes were as follows: nonsense (35.3%), frameshift (26.47%), splicing (23.52%), and missense (9%). Thirteen alterations (35.14%) were described for the first time. The data reported in this study add new information about MLH1 and MSH2 gene mutations and contribute to better characterize LS in Brazil, Uruguay and Argentina. The high rate of novel mutations demonstrates the importance of defining MLH1 and MSH2 mutations in distinct LS populations.

Mutations in SRCAP, encoding SNF2-related CREBBP activator protein, cause Floating-Harbor syndrome

Floating-Harbor syndrome (FHS) is a rare condition characterized by short stature, delayed osseous maturation, expressive-language deficits, and a distinctive facial appearance. Occurrence is generally sporadic, although parent-to-child transmission has been reported on occasion. Employing whole-exome sequencing, we identified heterozygous truncating mutations in SRCAP in five unrelated individuals with sporadic FHS. Sanger sequencing identified mutations in SRCAP in eight more affected persons. Mutations were de novo in all six instances in which parental DNA was available. SRCAP is an SNF2-related chromatin-remodeling factor that serves as a coactivator for CREB-binding protein (CREBBP, better known as CBP, the major cause of Rubinstein-Taybi syndrome [RTS]). Five SRCAP mutations, two of which are recurrent, were identified; all are tightly clustered within a small (111 codon) region of the final exon. These mutations are predicted to abolish three C-terminal AT-hook DNA-binding motifs while leaving the CBP-binding and ATPase domains intact. Our findings show that SRCAP mutations are the major cause of FHS and offer an explanation for the clinical overlap between FHS and RTS.

Predictive models for mutations in mismatch repair genes: implication for genetic counseling in developing countries

BACKGROUND

Lynch syndrome (LS) is the most common form of inherited predisposition to colorectal cancer (CRC), accounting for 2-5% of all CRC. LS is an autosomal dominant disease characterized by mutations in the mismatch repair genes mutL homolog 1 (MLH1), mutS homolog 2 (MSH2), postmeiotic segregation increased 1 (PMS1), post-meiotic segregation increased 2 (PMS2) and mutS homolog 6 (MSH6). Mutation risk prediction models can be incorporated into clinical practice, facilitating the decision-making process and identifying individuals for molecular investigation. This is extremely important in countries with limited economic resources. This study aims to evaluate sensitivity and specificity of five predictive models for germline mutations in repair genes in a sample of individuals with suspected Lynch syndrome.

METHODS

Blood samples from 88 patients were analyzed through sequencing MLH1, MSH2 and MSH6 genes. The probability of detecting a mutation was calculated using the PREMM, Barnetson, MMRpro, Wijnen and Myriad models. To evaluate the sensitivity and specificity of the models, receiver operating characteristic curves were constructed.

RESULTS

Of the 88 patients included in this analysis, 31 mutations were identified: 16 were found in the MSH2 gene, 15 in the MLH1 gene and no pathogenic mutations were identified in the MSH6 gene. It was observed that the AUC for the PREMM (0.846), Barnetson (0.850), MMRpro (0.821) and Wijnen (0.807) models did not present significant statistical difference. The Myriad model presented lower AUC (0.704) than the four other models evaluated. Considering thresholds of ≥ 5%, the models sensitivity varied between 1 (Myriad) and 0.87 (Wijnen) and specificity ranged from 0 (Myriad) to 0.38 (Barnetson).

CONCLUSIONS

The Barnetson, PREMM, MMRpro and Wijnen models present similar AUC. The AUC of the Myriad model is statistically inferior to the four other models.

Report of a Large Brazilian Family With a Very Attenuated Form of Hunter Syndrome (MPS II)

Hunter syndrome, or Mucopolysaccharidosis type II (MPS II), is a rare X-linked recessive disorder caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase (IDS). The phenotypic spectrum varies from severe to attenuated clinical forms. We report a large Brazilian family with 16 affected individuals exhibiting a very attenuated form of MPS II. Fourteen female carriers were also identified. Twelve affected male patients, whose ages ranged from 1 to 35 years, were examined. Molecular analysis showed a novel missense mutation (p.A77D) in the IDS gene, confirming the diagnosis. Nine of the family members presented some degree of heart damage, though only the proband became symptomatic and required heart transplantation. One 19-year-old adult and 1-year-old twin boys each had a normal echocardiogram. Short stature was found in two adults while macrocephaly was found in one; the remaining adults had anthropometric measures within normal range. All affected adults had normal cognitive development and were able to perform normal daily activities, except one who had mild learning disability. Two patients died due to natural causes beyond 70 years of age. The female carriers did not present any signs of disease. In this large family with a mild form of MPS II and variable degree of clinical manifestations, it is noteworthy that several affected individuals have remained asymptomatic even at advanced age and even without enzyme replacement therapy.

Three-year-old child with meroacrania - neurological signs

Neurological findings in a three-year-old child with meroacrania provide new insights into how the nervous system develops and functions in the absence of superior levels of control from the time of origin. The girl is the first child of a non-consanguineous white Brazilian couple, born at term, weighing 2650 g and measuring 44 cm in length. Upon examination at 43 months, she had quadriplegia, global hypotonia with occasional body hypertonia in a decorticate posture, hyperreflexia, ankle clonus, and extensor plantar response. This case allowed us to verify that, in the absence of upper structures and subcortical nuclei, there are clear signs that suggest corticospinal primacy in motor functions without a substitute pathway. Sound orientation responses suggest the independence of the vestibular-acoustic-ocular system, and manifestations of responsiveness to the environment raise questions about consciousness.

Two new Brazilian patients with Gómez-López-Hernández syndrome: reviewing the expanded phenotype with molecular insights

Gómez-López-Hernández (GLH) syndrome or cerebello-trigeminal dysplasia is a neurocutaneous syndrome whose etiology is unknown at the present time. We report two additional Brazilian patients, including the oldest one known to date (age 29). Here, we review the expanded phenotype in four patients with new clinical, psychiatric, radiological, and molecular investigations. One patient may have hypomania within the bipolar spectrum disorder with onset in childhood and adolescence. Primary growth hormone (GH) deficiency was ruled out in all patients, although one of them might have developed secondary GH deficiency due to partial hypopituitarism following severe hydrocephalus. Brain magnetic resonance angiography disclosed no azygous anterior cerebral artery (ACA) but only normal variants. Molecular analysis of the lysosomal acid phosphatase gene (ACP2) was performed, but no pathogenic mutations were identified. We present an overview of the phenotypic features of all patients described to date. There are currently 12 unrelated patients reported in the literature, 5 of whom are Brazilian. We discuss new molecular insights and speculate about the pathogenesis of GLH syndrome.

Splenopancreatic field abnormality is not unique to trisomy 13

Splenopancreatic fusion is an uncommon finding, usually only seen as part of the splenopancreatic field abnormality associated with trisomy 13. It may present itself either as ectopic splenic tissue in the cauda pancreatis, as ectopic pancreatic tissue in the spleen or accessory spleen, or as fusion of the cauda pancreatis and splenic hilum. In this study, we report four unrelated congenital anomaly cases presenting trisomy 21, osteocraniostenosis syndrome, isolated congenital heart defect, and oligohydramnios sequence due to prune belly syndrome, in which fusion was observed. This demonstrates that, although it may be more common in trisomy 13, this phenomenon should not be interpreted as pathognomonic to that syndrome.

A antibioticoterapia prévia sobre o infiltrado inflamatório pulmonar após isquemia e reperfusão intestinal: estudo experimental em ratos

A isquemia seguida de reperfusão intestinal (I/R) é um evento clínico comum que favorece a translocação bacteriana em órgãos à distância, como os pulmões. A antibioticoterapia prévia pode ser uma conduta eficaz para atenuar o desenvolvimento desse processo. Este esudo tem por finalidade reconhecer a concentração dos polimorfonucleares (PMN) nos septos alveolares em ratos, após indução de isquemia seguida de reperfusão intestinal, com e sem antibioticoterapia prévia. Utilizaram-se 48 ratos divididos, aleatoriamente em 6 grupos (A,B,C,D,E,F)com 8 animais cada um. Os grupos A,C e E não receberam antibiótico,e os grupos B, D e F receberam 500mg/Kg de eritromicina por via oral. Os grupos A e B serviram de controle; C e D induziu-se isquemia intestinaL por 30 min; e os grupos E e F seguiu-se à isquemia, reperfusão por 30 min. Em seguida, abriu-se o tórax e ressecaram-se os pulmões, sendo encaminhados para análise histopatológica e histométrica, obtendo-se uma média de PMN nos septos alvéolos. O grupo controle(A) apresentou média de 4,2 PMN campo nos septos; o grupo isquêmico(C), 13,6 e o reperfundido (E), 17,5. A comparação entre as médias dos grupos A e C e A e E tiveram p<0,0001. Entretanto, a comparação entre os grupos C e E não foi significante (p=0,095). A média de PMN por campo foi de 8,6 no grupo B; 9,9 no grupo D e 12,9 no grupo F. A comparação entre os grupos B e D teve p=0,007. A comparação entre os grupos que receberam ou não antibiótico permitiu verificar que o número de PMN do grupo B foi o dobro do grupo A (p=0,004). O grupo C apresentou maior concentração de PMN que o grupo D (p=0,019). No grupo E, houve maior concentração de PMN que no grupo F (p=0,014). Pode-se concluir que: (1) a isquemia intestinal levou a maior concentração de PMN nos septos alveolares; (2) a antibioticoterapia prévia aumentou o infiltrado inflamatório pulmonar nos alvéolos dos ratos com intestino normal; (3) nos septos alveolares dos animais submetidos a I/R, a densidade de PMN foi maior que nos não reperfundidos e (4) a antibioticoterapia prévia diminuiu significantemente a concentração de PMN após I/R.