PSAT106 Infigratinib in Children with Achondroplasia: Design of the PROPEL, PROPEL2 and PROPEL OLE Studies

Background

Achondroplasia (ACH), the most common non-lethal form of skeletal dysplasia, is characterized by defective endochondral ossification resulting from gain-of-function mutations in the fibroblast growth factor receptor 3 (FGFR3) gene, a negative regulator of endochondral bone formation. Infigratinib, a selective, orally bioavailable FGFR1–3 tyrosine kinase inhibitor, has been shown to reverse established growth arrest in chondrocytes and improve foramen magnum and long bone length in Fgfr3Y367C/+ mice. Infigratinib is being investigated for the treatment of ACH in the PROPEL program of three clinical trials: 1) PROPEL, designed to collect information on the natural history of ACH; 2) PROPEL2, designed to obtain preliminary evidence of efficacy and safety and to identify the dose of infigratinib to investigate further; 3) PROPEL OLE, which is designed to evaluate the long-term efficacy and safety of infigratinib in children with ACH.

Methods

PROPEL (NCT04035811) is a non-interventional clinical assessment study designed to characterize the natural history of up to 200 children aged 2.5–10 years with ACH over a 6−24-month period. The primary objective is to collect baseline height velocity measurements in children who may participate in an interventional study with infigratinib. The primary endpoint is the annualized growth velocity (AGV). Further objectives are to collect other baseline growth measurements, evaluate exploratory biomarker indicators of growth, and assess ACH-related medical events reported as medical history, or non-treatment adverse events (AEs).

PROPEL2 (NCT04265651) is a phase 2, open-label study of infigratinib in children aged 3−11 years with ACH who completed ≥6 months observation in PROPEL. PROPEL2 includes dose-escalation with an extended dose-finding treatment phase (n≈40), a pharmacokinetics sub-study (n≈18), followed by a dose-expansion phase (n≈20) in which children receive infigratinib for 12 months to confirm the selected dose and provide evidence of efficacy. Primary endpoints are treatment-emergent AEs, change from baseline in AGV, and infigratinib pharmacokinetics. Secondary endpoints include safety/tolerability of infigratinib and changes from baseline in anthropometric parameters, including body proportions. Exploratory outcomes include changes in QoL and other parameters of disease burden.

PROPEL OLE (NCT05145010) is a phase 2, open-label extension study in up to 230 children who completed an interventional study with infigratinib and, potentially, in ≤50 who are infigratinib-naive. The primary objectives are to evaluate safety, tolerability, and efficacy of long-term daily doses of infigratinib. Secondary objectives include evaluation of changes in other indicators of growth and development, and evaluation of QoL and disease burden. Children will receive infigratinib until they reach final/near final height.

Summary

PROPEL, PROPEL2, and PROPEL OLE are currently ongoing. Together, these studies are intended to provide key evidence on the safety and efficacy of oral infigratinib in children with ACH and will inform the design of future studies in this setting.

Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

PSAT105 Evaluation of Body Mass Index and Metabolic Parameters in Children with Achondroplasia Participating in the PROPEL Study

Background

Achondroplasia (ACH) is the most common short-limbed skeletal dysplasia, affecting between 1 in 15,000 to 1 in 30,000 live births. Children and adults with ACH have disproportionate short stature and are at risk for several significant co-morbidities, including obstructive sleep apnea, chronic otitis media with conductive hearing loss, and spinal stenosis. Obesity is a health problem in ACH and aggravates breathing difficulties (i.e. sleep apnea), back and joint pain, and reduced mobility. Individuals with ACH are predisposed to abdominal obesity, although the cause is not completely understood. The metabolic effect of visceral obesity does not suggest an association with the development of a diabetic profile. The objective of this study is to evaluate body mass index (BMI) and metabolic parameters in children with ACH participating in the PROPEL study, a prospective, non-interventional study designed to examine baseline growth parameters and health status in children being assessed for potential enrollment into interventional studies with infigratinib, an oral FGFR1–3 inhibitor in development for ACH.

Methods

Data were analyzed from 86 children (mean age 6.1±2.5 years; female n=52) enrolled in PROPEL. BMI was calculated at enrollment and compared with sex- and age-specific BMI curves for children with ACH in the United States. Cholesterol, triglycerides, and hemoglobin A1c were measured centrally in a subset of children.

Results

BMI (mean±SD) was 21.2±2.2 in females (range 16.8–26.2) and 20.5±1.6 in males (range 17.9–24.6), with 8/52 girls (15%) and 1/34 boys (2.9%) presenting BMI above the 95% of the sex- and age-specific BMI curves for ACH. The mean±SD for cholesterol and triglycerides measured in a subset of 43 children were 4.2±0.7 mmol/L (normal range [NR] 2.59–4.66) and 0.9±0.5 mmol/L (NR 0.56–1.36), respectively. Cholesterol was elevated in 9/43 children (20.9%), while triglycerides were high in 8/43 (18.7%). Hemoglobin A1c (HbA1c) was measured in 28 children and had a mean±SD of 0.052±0.002 (NR Hb fraction 0.04–0.06). Although all values were within normal ranges, 19/28 (68%) of children had values above the mean for laboratory reference values.

Conclusion

Results from this work illustrate the importance of using BMI tables developed for children with ACH when providing guidance on weight management. Furthermore, our findings suggest that, in this cohort, average cholesterol and HbA1c levels, although normal, are above the mean for the reference population; this highlights the importance of a healthy diet, weight management and regular physical activity starting at young age. Additional studies are needed to understand the relationship between BMI and body composition in individuals with short stature and to further investigate the clinical relevance of these findings given that no association between increased BMI and metabolic syndrome has been described in adults with ACH.

Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

RF26 | PMON326 Medical History of Children Enrolled in PROPEL: A Prospective Clinical Assessment Study in Children with Achondroplasia

Background

Achondroplasia (ACH) is the most common short-limbed skeletal dysplasia, affecting between 1 in 15,000 to 1 in 30,000 live births. People with ACH are at risk for several significant co-morbidities, including foramen magnum stenosis, obstructive sleep apnea, chronic otitis media with conductive hearing loss, spinal stenosis, and a propensity towards obesity. PROPEL is a prospective, non-interventional study designed to examine baseline growth parameters and health status in children being assessed for potential enrollment into interventional studies with infigratinib, an oral FGFR1–3 inhibitor in development as a therapeutic option for ACH. Here we describe the medical complications reported as medical history in the PROPEL study.

Methods

Children with ACH between the ages of 2.5 and 10 years are eligible for enrollment in PROPEL and are evaluated at screening/baseline, month 3, month 6, and every 6 months thereafter. Medical history collected at screening/baseline is summarized using system organ class and preferred terms.

Results

A total of 86 children with ACH (60% female, mean±SD age 6.1±2.5 years) have been enrolled to date at 19 sites in Europe, Australia and North America. Fifty-eight children had undergone surgical and medical procedures with a mean of 2.9 procedures per child (1–11 surgeries/subject). The most common procedures were pressure-equalizing ear tube insertion, adenoidectomy and tonsillectomy. Twenty-one (24%) children had undergone at least 1 surgery (1–5 surgeries/child) for spine or cranial decompression. History of infections and respiratory disorders were reported in 46 (53%) and 40 (47%) children, respectively, the most common being ear infections and obstructive sleep apnea. Musculoskeletal disorders were described in 33 (38%) children, with kyphosis being the most common. Hydrocephalus was reported in 2 children, while 4 had ventriculomegaly without intracranial hypertension. Congenital cardiovascular abnormalities were found in 4 children, 2 of whom presented with patent ductus arteriosus and 2 had patent foramen ovale. A comprehensive summary of medical histories will be presented at the conference.

Conclusions

The PROPEL study has a planned total enrollment of 200 children and seeks to contribute to the deeper understanding of the natural history of ACH. Data described here highlight the significant complications and high number of interventions that children with ACH undergo throughout infancy and childhood. This stresses the importance of expert management of this complex condition.

Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m., Monday, June 13, 2022 1:05 p.m. - 1:10 p.m.

Infigratinib in children with achondroplasia: the PROPEL and PROPEL 2 studies

Background:

Achondroplasia is the most common short-limbed skeletal dysplasia resulting from gain-of-function pathogenic variants in fibroblast growth factor receptor 3 ( FGFR3) gene, a negative regulator of endochondral bone formation. Most treatment options are symptomatic, targeting medical complications. Infigratinib is an orally bioavailable, FGFR1–3 selective tyrosine kinase inhibitor being investigated as a direct therapeutic strategy to counteract FGFR3 overactivity in achondroplasia.

Objectives:

The main objective of PROPEL is to collect baseline data of children with achondroplasia being considered for future enrollment in interventional studies sponsored by QED Therapeutics. The objectives of PROPEL 2 are to obtain preliminary evidence of safety and efficacy of oral infigratinib in children with achondroplasia, to identify the infigratinib dose to be explored in future studies, and to characterize the pharmacokinetic (PK) profile of infigratinib and major metabolites.

Design:

PROPEL (NCT04035811) is a prospective, noninterventional clinical study designed to characterize the natural history and collect baseline data of children with achondroplasia over 6−24 months. PROPEL 2 (NCT04265651), a prospective, phase II, open-label study of infigratinib in children with achondroplasia, consists of a dose-escalation, dose-finding, and dose-expansion phase to confirm the selected dose, and a PK substudy.

Methods and analysis:

Children aged 3−11 years with achondroplasia who completed ⩾6 months in PROPEL are eligible for PROPEL 2. Primary endpoints include treatment-emergent adverse events and change from baseline in annualized height velocity. Four cohorts at ascending dose levels are planned for dose escalation. The selected dose will be confirmed in the dose-expansion phase.

Ethics:

PROPEL and PROPEL 2 are being conducted in accordance with the International Conference on Harmonization Good Clinical Practice guidelines, principles of the Declaration of Helsinki, and relevant human clinical research and data privacy regulations. Protocols have been approved by local health authorities, ethics committees, and institutions as applicable. Parents/legally authorized representatives are required to provide signed informed consent; signed informed assent by the child is also required, where applicable.

Discussion:

PROPEL and PROPEL 2 will provide preliminary evidence of the safety and efficacy of infigratinib as precision treatment of children with achondroplasia and will inform the design of future studies of FGFR-targeted agents in achondroplasia.

Registration:

ClinicalTrials.gov: NCT04035811; NCT04265651.

Persistent and Stable Growth Promoting Effects of Vosoritide in Children With Achondroplasia for up to 2 Years: Results From the Ongoing Phase 3 Extension Study

Objectives: Vosoritide is a potent stimulator of endochondral bone growth and is in development for the treatment of achondroplasia, the most common form of disproportionate short stature. We previously reported on a 52-week, phase 3, pivotal study that demonstrated a highly statistically significant improvement in annualized growth velocity (AGV) when vosoritide was compared to placebo in children with achondroplasia aged 5-18 years (Savarirayan et al, Lancet, 2020). This is an analysis of data after an additional 52 weeks of treatment in the ongoing phase 3 extension study. Methods: After completion of the phase 3 placebo-controlled study, 119 children were enrolled into the extension study, where they all receive open label 15 μg/kg/day vosoritide. AGV, height Z-score and body proportion ratio were analyzed to assess efficacy of vosoritide in children who were treated with vosoritide for up to 2 years. Fifty-eight continued treatment with vosoritide and 61 switched from placebo to vosoritide. Two participants on continuous vosoritide treatment discontinued before the Week 52 timepoint. Four participants on continuous vosoritide treatment and 7 participants who switched from placebo to vosoritide missed the Week 52 assessment due to Covid-19. Results: In children randomized to receive daily vosoritide, baseline mean (SD) AGV was 4.26 (1.53) cm/year. After the first 52 weeks of treatment, mean (SD) AGV was 5.67 (0.98) cm/year. Mean (SD) AGV over the second year was 5.57 (1.10) cm/year. Mean (SD) change from baseline in height Z-score improved by +0.24 (0.31) at Week 52 in the pivotal study and +0.45 (0.56) at Week 52 in the extension study. Mean (SD) upper-to-lower body segment ratio improved with a change from baseline of -0.03 (0.11) at Week 52 in the pivotal study and -0.09 (0.11) at Week 52 in the extension study. In children who switched from placebo to vosoritide after 52 weeks, baseline AGV was 4.06 (1.20) cm/year and 3.94 (1.07) cm/year after 52 weeks on placebo. In the second year, after receiving 52 weeks of vosoritide, mean AGV was 5.65 (1.47) cm/year, the mean (SD) change in height Z-score was +0.24 (0.34), and the change in upper-to-lower body segment ratio was -0.03 (0.08). No new adverse events associated with vosoritide treatment were detected with up to 2 years of continuous daily, subcutaneous treatment. Most adverse events were mild and no serious adverse events were attributed to vosoritide. The most common adverse event remains mild and transient injection site reactions. Conclusions: The effect of vosoritide administration on growth as measured through AGV and height Z-score was maintained for up to 2-years in children with achondroplasia aged 5 to 18 years, with an improvement of body proportions.

CHARGE syndrome in the era of molecular diagnosis: Similar outcomes in those without coloboma or choanal atresia

CHARGE syndrome (OMIM 214800) is a condition characterized by multisystem involvement with CHD7 pathogenic mutations leading to disease in the majority of patients. Discovery of the molecular cause of CHARGE unmasked a larger phenotypic spectrum than was previously appreciated. Within our interdisciplinary CHARGE syndrome program, we sought to characterize our CHD7-positive CHARGE cohort without coloboma or choanal atresia, highlighting complications and outcomes. We describe 18 individuals with CHD7-confirmed diagnosis from 15 families. The most sensitive finding in the cohort was temporal bone malformations, present in 13/15 individuals. Individuals had an average of 1.6 major features and 3.3 minor features defined by the Blake et al. guidelines. Despite lack of major features or major malformations, the majority of individuals continued to have difficulties with pneumonia, aspiration, secretion management and motility issues that greatly impacted their lives. Our findings illustrate the need for molecular testing and timely recognition given that the major co-morbidities are frequently experienced by patients with the mildest clinical spectrum of CHARGE syndrome.

Expanding Genetic and Functional Diagnoses of IGF1R Haploinsufficiencies

BACKGROUND

The growth-promoting effects of IGF-I is mediated through the IGF-I receptor (IGF1R), a widely expressed cell-surface tyrosine kinase receptor. IGF1R copy number variants (CNV) can cause pre- and postnatal growth restriction or overgrowth.

METHODS

Whole exome sequence (WES), chromosomal microarray, and targeted IGF1R gene analyses were performed on 3 unrelated children who share features of small for gestational age, short stature, and elevated serum IGF-I, but otherwise had clinical heterogeneity. Fluorescence-activated cell sorting (FACS) analysis of cell-surface IGF1R was performed on live primary cells derived from the patients.

RESULTS

Two novel IGF1R CNV and a heterozygous IGF1R nonsense variant were identified in the 3 patients. One CNV (4.492 Mb) was successfully called from WES, utilizing eXome-Hidden Markov Model (XHMM) analysis. FACS analysis of cell-surface IGF1R on live primary cells derived from the patients demonstrated a ∼50% reduction in IGF1R availability associated with the haploinsufficiency state.

CONCLUSION

In addition to conventional methods, IGF1R CNV can be identified from WES data. FACS analysis of live primary cells is a promising method for efficiently evaluating and screening for IGF1R haploinsufficiency. Further investigations are necessary to delineate how comparable IGF1R availability leads to the wide spectrum of clinical phenotypes and variable responsiveness to rhGH therapy.

Functional validation of novel compound heterozygous variants in B3GAT3 resulting in severe osteopenia and fractures: expanding the disease phenotype

Background

A new disease class of syndromes, described as linkeropathies, which are derived from defects in the glycosaminoglycan-linker region as well as glycosaminoglycan-side chains of proteoglycans is increasingly being recognized as a cause of human disease. Proteoglycans are an essential component of the extracellular matrix. Defects in the enzymatic process of proteoglycan synthesis broadly occur due to the incorrect addition of side chains. Previously, homozygous missense variants within the B3GAT3 gene encoding beta 1,3 glucuronyltransferase 3(GlcAT-I) responsible for the biosynthesis of glycosaminoglycans have been described in 7 individuals.

Case presentation

In this study, a 4-year-old patient with a severe phenotype of osteoporosis, hypotonia, joint laxity, fractures, scoliosis, biscuspid aortic valve and myopia was referred for next generation sequencing after extensive negative clinical testing. Whole exome sequencing was performed on the proband and his unaffected parents to identify the molecular basis of his disease. Sequencing revealed compound heterozygous variants in B3GAT3: c.1A > G (p.Met1?) and c.671 T > A (p.L224Q). Clinical and in vitro functional studies were then completed to verify the pathogenicity of the genotype and further characterize the functional basis of the patient’s disease demonstrating the patient had a decrease both in the protein level of B3GAT3 and in the glucuronyltransferase activity when compared to control samples. Independent in vitro assessment of each variant confirmed the B3GAT3: c.1A > G (p.Met1?) variant is functionally null and the c.671 T > A (p.L224Q) missense variant has significantly reduced glucuronyltransferase activity (~3% of control).

Conclusions

This is the first report of a patient with compound heterozygosity for a null variant in trans with a missense in B3GAT3 resulting in a severe phenotype, expanding both the genotypic and phenotypic spectrum of B3GAT3-related disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-016-0344-9) contains supplementary material, which is available to authorized users.

Cost analysis of mandibular distraction versus tracheostomy in neonates with Pierre Robin sequence

OBJECTIVE

To evaluate costs associated with surgical treatment for neonates with Pierre Robin sequence (PRS).

STUDY DESIGN

Retrospective cohort study.

SETTING

Cincinnati Children's Hospital Medical Center.

SUBJECTS AND METHODS

With Institutional Review Board approval, we retrospectively studied neonates with PRS treated from 2001 to 2009 with either tracheostomy (Trach), mandibular distraction (MD), or Trach with subsequent MD (Trach+MD). Actual charges over a 3-year period associated with operative costs, hospital stay, imaging and sleep studies, clinic visits, and related emergency room visits were collected. Home tracheostomy care charges were estimated individually for each patient. Charges were compared using regression and appropriate statistical analyses.

RESULTS

Forty-seven neonates were included in the study (MD, n = 26; Trach, n = 12; Trach+MD, n = 9). Trach group patients had 2.6-fold higher charges than the MD group despite no difference in length of hospital stay. This difference increased to 7.3-fold when including home trach care-related costs. Trach+MD group patients had longer hospital lengths of stay and higher operation room (OR) fees, but no increased total charges compared with the Trach only group.

CONCLUSIONS

For patients with severe PRS, mandibular distraction provides significant cost savings over tracheostomy ($300,000 per patient over 3 years). Increased costs with tracheostomy come from greater hospital-related charges, more frequent airway procedures, a higher incidence of gastrostomy tube feeds, and home trach care costs. A careful examination of long-term outcomes will be critical as mandibular distraction continues to gain acceptance for treatment of PRS.

Duration of tamoxifen use and the risk of contralateral breast cancer in BRCA1 and BRCA2 mutation carriers

Women with a mutation in BRCA1 or BRCA2 face a lifetime risk of breast cancer of approximately 80 %. Tamoxifen treatment of the first cancer has been associated with a reduction in the risk of a subsequent contralateral cancer. We studied 1,504 women with a known BRCA1 or BRCA2 mutation, 411 women with bilateral breast cancer (cases) and 1,093 women with unilateral breast cancer (controls) in a matched case-control study. Control women were of similar age and had a similar age of diagnosis of first breast cancer as the cases. For each woman who used tamoxifen, the starting and stopping dates were abstracted and the duration of tamoxifen use was calculated. Three hundred and thirty-one women had used tamoxifen (22 %); of these 84 (25 %) had completed four or more years of tamoxifen, the remainder stopped prematurely or were current users. For women with up to 1 year of tamoxifen use, the odds ratio for contralateral breast cancer was 0.37 (95 % CI 0.20-0.69; p = 0.001) compared to women with no tamoxifen use. Among women with 1-4 years of tamoxifen use the odds ratio was 0.53 (95 % CI 0.32-0.87; p = 0.01). Among women with four or more years of tamoxifen use the odds ratio was 0.83 (95 % CI 0.44-1.55; p = 0.55). Short-term use of tamoxifen for chemoprevention in BRCA1 and BRCA2 mutation carriers may be as effective as a conventional 5-year course of treatment.

The impact of pregnancy on breast cancer survival in women who carry a BRCA1 or BRCA2 mutation

Physicians are often approached by young women with a BRCA mutation and a recent history of breast cancer who wish to have a baby. They wish to know if pregnancy impacts upon their future risks of cancer recurrence and survival. To date, there is little information on the survival experience of women who carry a mutation in one of the BRCA genes and who become pregnant. From an international multi-center cohort study of 12,084 women with a BRCA1 or BRCA2 mutation, we identified 128 case subjects who were diagnosed with breast cancer while pregnant or who became pregnant after a diagnosis of breast cancer. These women were age-matched to 269 mutation carriers with breast cancer who did not become pregnant (controls). Subjects were followed from the date of breast cancer diagnosis until the date of last follow-up or death from breast cancer. The Kaplan-Meier method was used to estimate 15-year survival rates. The hazard ratio for survival associated with pregnancy was calculated using a left-truncated Cox proportional hazard model, adjusting for other prognostic factors. Among women who were diagnosed with breast cancer when pregnant or who became pregnant thereafter, the 15-year survival rate was 91.5 %, compared to a survival of 88.6 % for women who did not become pregnant (adjusted hazard ratio = 0.76; 95 % CI 0.31-1.91; p = 0.56). Pregnancy concurrent with or after a diagnosis of breast cancer does not appear to adversely affect survival among BRCA1/2 mutation carriers.

Prevalence of transposed teeth as seen on panoramic radiographs in children with cleft lip and palate

OBJECTIVE

To assess the prevalence of complete and incomplete transpositions of teeth in subjects with repaired cleft lip and/or palate.

DESIGN

Retrospective review. Panoramic radiographs from 364 subjects with repaired cleft lip and/or palate and with or without syndromes were compared with 364 panoramic radiographs from noncleft controls. The percentages of completely or incompletely transposed teeth, missing teeth, and pegged teeth were recorded for each subject and control.

SETTING

Primary care dental clinic in a university affiliated, not-for-profit hospital.

MAIN OUTCOME MEASURES

Presence of complete and incomplete transposed teeth, missing teeth, and pegged teeth detected on subjects' panoramic radiographs.

RESULTS

This study revealed greater prevalence of tooth transposition in subjects with cleft lip and/or palate (52/364 = 14.3%) as compared with noncleft controls (1/364 = 0.3%; P < .001).

CONCLUSIONS

There was a higher prevalence of tooth transpositions in subjects with repaired cleft lip and/or palate with/or without syndromes than in noncleft controls. There was a weak association between transpositions and missing teeth (P = .12) and between transpositions and pegged teeth (.23).

Genotypic and phenotypic analysis of 396 individuals with mutations in Sonic Hedgehog

BACKGROUND

Holoprosencephaly (HPE), the most common malformation of the human forebrain, may result from mutations in over 12 genes. Sonic Hedgehog (SHH) was the first such gene discovered; mutations in SHH remain the most common cause of non-chromosomal HPE. The severity spectrum is wide, ranging from incompatibility with extrauterine life to isolated midline facial differences.

OBJECTIVE

To characterise genetic and clinical findings in individuals with SHH mutations.

METHODS

Through the National Institutes of Health and collaborating centres, DNA from approximately 2000 individuals with HPE spectrum disorders were analysed for SHH variations. Clinical details were examined and combined with published cases.

RESULTS

This study describes 396 individuals, representing 157 unrelated kindreds, with SHH mutations; 141 (36%) have not been previously reported. SHH mutations more commonly resulted in non-HPE (64%) than frank HPE (36%), and non-HPE was significantly more common in patients with SHH than in those with mutations in the other common HPE related genes (p<0.0001 compared to ZIC2 or SIX3). Individuals with truncating mutations were significantly more likely to have frank HPE than those with non-truncating mutations (49% vs 35%, respectively; p=0.012). While mutations were significantly more common in the N-terminus than in the C-terminus (including accounting for the relative size of the coding regions, p=0.00010), no specific genotype-phenotype correlations could be established regarding mutation location.

CONCLUSIONS

SHH mutations overall result in milder disease than mutations in other common HPE related genes. HPE is more frequent in individuals with truncating mutations, but clinical predictions at the individual level remain elusive.

Hepatic mesenchymal hamartoma: cytogenetic analysis of a case and review of the literature

Hepatic mesenchymal hamartoma (HMH) is a rare benign liver tumor generally occurring in young children. Abnormalities of chromosome 19q13.4 and chromosomal aneuploidy detected by flow cytometry have been reported in HMH. We recently analyzed a HMH in a 14-month-old girl and identified additional novel chromosome abnormalities, including hypodiploidy with deletions of several chromosomes, without rearrangement of 19q13.4 on both routine chromosome analysis and fluorescent in-situ hybridization analysis using subtelomere probes for chromosome 19q. This case underscores the need for chromosome analysis of all HMH and the need to report these changes to better understand the pathophysiology and the entire spectrum of cytogenetics of this uncommon tumor.

Rapid progression of prostate cancer in men with a BRCA2 mutation

Men with BRCA2 mutations have been found to be at increased risk of developing prostate cancer. There is a recent report that BRCA2 carriers with prostate cancer have poorer survival than noncarrier prostate cancer patients. In this study, we compared survival of men with a BRCA2 mutation and prostate cancer with that of men with a BRCA1 mutation and prostate cancer. We obtained the age at diagnosis, age at death or current age from 182 men with prostate cancer from families with a BRCA2 mutation and from 119 men with prostate cancer from families with a BRCA1 mutation. The median survival from diagnosis was 4.0 years for men with a BRCA2 mutation vs 8.0 years for men with a BRCA1 mutation, and the difference was highly significant (P<0.01). It may be important to develop targeted chemotherapies to treat prostate cancer in men with a BRCA2 mutation.

Tamoxifen and contralateral breast cancer inBRCA1 andBRCA2 carriers: An update

Women with a mutation in BRCA1 or BRCA2 face a lifetime risk of breast cancer of approximately 80%, and following the first diagnosis the 10-year risk of contralateral breast cancer is approximately 30%. It has been shown that both tamoxifen and oophorectomy prevent contralateral breast cancer, but it is not clear whether there is a benefit in giving tamoxifen to women who have previously undergone an oophorectomy. Furthermore, the relative degree of protection in BRCA1 and BRCA2 carriers has not been well evaluated. We studied 285 women with bilateral breast cancer and a BRCA1 or BRCA2 mutation, and 751 control women with unilateral breast cancer and a BRCA1 or BRCA2 mutation in a matched case-control study. Control women were of similar age and had a similar age of diagnosis of breast cancer and had been followed for as long as the case for a second primary breast cancer. The history of tamoxifen use for treating the first breast cancer was compared between bilateral and unilateral cases. The multivariate odds ratio for contralateral breast cancer associated with tamoxifen use was 0.50 for carriers of BRCA1 mutations (95% CI, 0.30-0.85) and was 0.42 for carriers of BRCA2 mutations (95% CI, 0.17-1.02). The protective effect of tamoxifen was not seen among women who had undergone an oophorectomy (OR = 0.83; 95%CI, 0.24-2.89) but this subgroup was small. In contrast, a strong protective effect of tamoxifen was apparent among women who were premenopausal or who had undergone natural menopause (OR = 0.44; 95% CI, 0.27-0.65).

Identification and characterization of a novel gene disrupted by a pericentric inversion inv(4)(p13.1q21.1) in a family with cleft lip

Cleft lip with or without cleft palate is a common birth defect affecting 1 in every 700 live births. Several genetic loci are believed to be involved in the pathogenesis of syndromic and non-syndromic clefting. We identified a pericentric inversion of chromosome 4, inv(4)(p13q21) that segregates with cleft lip in a two-generation family. By using a combination of fluorescence in situ hybridization, yeast artificial chromosome, bacterial artificial chromosome contig mapping, and database searching we mapped and sequenced the inversion breakpoint region. The pericentric inversion disrupts a gene (ACOD4) on chromosome 4q21 that codes for a novel acyl-CoA desaturase enzyme. The 3.0 kb human ACOD4 cDNA spans approximately 170 kb and is composed of five exons of ACOD4. The inversion breakpoint is located in the second exon. The 3.0 kb mRNA is expressed at high level in fetal brain; a lower expression level was found in fetal kidney. No expression of ACOD4 was detected in fetal lung or liver or in adult tissues. The five exons code for a protein of 330 amino acids, with a predicted molecular weight of 37.5 kDa. The protein is highly similar to acyl-CoA desaturases from Drosophila melanogaster to Homo sapiens. The catalytically essential histidine clusters and the potential transmembrane domains are well conserved.

Molar pregnancy coexisting with a normal fetus: a case report

Molar pregnancy with a coexisting live fetus is a rare occurrence. We present morphologic and cytogenetic analysis of a recent case. Cytogenetic studies revealed a 46, XX karyotype for the fetus, the normal placenta, and the abnormal placenta. Chromosome banding studies confirmed the presence of maternal and paternal chromosomes in all three tissues. These studies favored the possibility that both tumor and fetus arose from a single gestation. Subsequently, the patient required chemotherapy for low-risk, metastatic trophoblastic disease.

Molecular detection of a translocation (Y;15) in a 45,X male

A 45,X male individual was shown to have a translocation of Y-chromosome material to the short arm or proximal long arm of chromosome 15. This translocation was detected by genomic DNA blotting and in situ hybridization with Y-chromosome-specific DNA probes.

Small deletions of the short arm of the Y chromosome in 46,XY females

Structural anomalies of the sex chromosomes provide a means to study the location of genes responsible for sex determination. Recently, a type of sex reversal in humans, the 46,XX male, was shown to result in some cases from translocation of Y chromosome material to the X chromosome. In the present report, another type of sex reversal, the 46,XY female, is shown to result, in two cases, from small deletions of the short arm of the Y chromosome. Prometaphase chromosome analysis showed a 46,X,Yp- karyotype. Several Y chromosome-specific DNA probes were found to be deleted in the two female patients. DNA analysis showed that the two deletions were different but included a common overlapping region likely to be essential for male determination.

Quantitative analysis of sex-chromosome mosaicism with X-Y DNA probes

Sex-chromosome mosaicism was quantitatively analyzed in two patients using DNA probes specific for human X and Y chromosomes. Both patients were female with stigmata of the Turner syndrome, and both had a 45,X cell line and a 46,XY cell line. One of the patients had a morphologically abnormal, nonfluorescent Y chromosome, dic(Y)(q11). Hybridization of DNA from this patient with two repetitive DNA sequences specific for the heterochromatic region of the Y chromosome indicated that most of the Y-heterochromatic sequences were deleted. DNA from both patients was hybridized with a probe for the DXYS1 locus and found to have the X- and Y-linked loci. Densitometric measurements of the relative intensities of the X- and Y-linked bands were used to calculate the degree of mosaicism in each case. The percentages of 45,X cells obtained by DNA analysis agreed with those obtained by chromosome analysis. DNA analysis provides a way to quantitate mosaicism at the DNA level and in nondividing tissue.

Fatigue Crack Growth in Notched Parts With Compressive Mean Load

A fracture mechanics model is proposed to describe fatigue crack propagation in notched specimens. This model accounts for residual stresses which are present at the notch root after unloading from maximum compressive load. This is of particular interest for specimens subjected to compressive mean load. According to the model, cracks will stop growing at the boundary of the plastically deformed zone if the specimen is subjected to compressive load only. Validity of the model was verified with notched specimens of mild steel.