Deletion of the dosage sensitive gene NR0B1 encoding DAX1 on chromosome Xp21.2 results in congenital adrenal hypoplasia (AHC), whereas NR0B1 duplication in 46,XY individuals leads to gonadal dysgenesis and a female phenotype. We describe a 21-year-old 46,XY female manifesting primary amenorrhea, a small immature uterus, gonadal dysgenesis, and notably absent adrenal insufficiency with a submicroscopic (257 kb) deletion upstream of NR0B1. We hypothesize that loss of regulatory sequences may have resulted in position effect up-regulation of DAX1 expression, consistent with phenotypic consequences of NR0B1 duplication. We propose that this genomic region and by extension those surrounding the dosage sensitive SRY, SOX9, SF1, and WNT-4 genes, should be examined for copy-number variation in patients with sex reversal.

To determine the phenotype and natural history of a founder genetic subtype of autosomal dominant arrhythmogenic right ventricular cardiomyopathy (ARVC) caused by a p.S358L mutation in TMEM43. The age of onset of cardiac symptoms, clinical events and test abnormalities were studied in 412 subjects (258 affected and 154 unaffected), all of which occurred in affected males significantly earlier and more often than unaffected males. Affected males were hospitalized four times more often than affected females (p ≤ 0.0001) and died younger (p ≤ 0.001). The temporal sequence from symptoms onset to death was prolonged in affected females by 1-2 decades. The most prevalent electrocardiogram (ECG) manifestation was poor R wave progression (PRWP), with affected males twice as likely to develop PRWP as affected females (p ≤ 0.05). Left ventricular enlargement (LVE) occurred in 43% of affected subjects, with 11% fulfilling criteria for dilated cardiomyopathy. Ventricular ectopy on Holter monitor was common and occurred early: the most diagnostically useful clinical test. No symptom or test could rule out diagnosis. This ARVC subtype is a sex-influenced lethal arrhythmogenic cardiomyopathy, with a unique ECG finding, LV dilatation, heart failure and early death, where molecular pre-symptomatic diagnosis has the greatest clinical utility.

Purpose: Newfoundland has one of the highest rates of colorectal cancer in North America.The most common hereditary form of colorectal cancer is hereditary nonpolyposis colorectal cancer caused by mutations in genes involved in mismatch repair. Our purpose was to determine the proportion of hereditary colorectal cancer and to determine the genetic basis of disease in both population and clinically referred cohorts from Newfoundland. Experimental Design: Seventy-eight colorectal cancer patients were accrued over a 2-year period from the Avalon Peninsula of Newfoundland. We also examined 31 hereditary nonpolyposis colorectal cancer^like families, which had been referred to the Provincial Medical Genetics Program. Tumors from probands were tested by immunohistochemistry for deficiencies in MLH1, MSH2, and MSH6 proteins and tested for DNA microsatellite instability. Mutation analyses of MLH1, MSH2, and MSH6 were undertaken by direct sequencing and an assay to detect deletions, amplifications, and rearrangements in MSH2 and MLH1. Results: We identified eight population-based families that fulfill the Amsterdam I or II criteria, 4 (50%) of which seem to have hereditary cancer not attributable to the most commonly mutated mismatch repair genes. In addition, in 16 of 21 (76%) referred families fulfilling Amsterdam I or II criteria, no mutations were found in the three most commonly altered mismatch repair genes, and tumor analyses corroborated these findings. Conclusions: It seems that strong and novel genetic causes of hereditary colorectal cancer are responsible for a high proportion of colorectal cancer in this population. Conditions are suitable for the identification of these genes by linkage studies of large Newfoundland cancer families.

Background— We previously showed a survival benefit of the implantable cardioverter defibrillator (ICD) in males with arrhythmogenic right ventricular cardiomyopathy caused by a p.S358L mutation in TMEM43 . We present long-term data (median follow-up 8.5years) after ICD for primary (PP) and secondary prophylaxis in males and females, determine whether ICD discharges for ventricular tachycardia/ventricular fibrillation were equivalent to an aborted death, and assess relevant clinical predictors. Methods and Results— We studied 24 multiplex families segregating an autosomal dominant p.S358L mutation in TMEM43 . We compared survival in 148 mutation carriers with an ICD to 148 controls matched for age, sex, disease status, and family. Of 80 male mutation carriers with ICDs (median age at implantation 31 years), 61 (76%) were for PP; of 68 females (median age at implantation 43 years), 66 (97%) were for PP. In males, irrespective of indication, survival was better in the ICD groups compared with control groups (relative risk 9.3 [95% confidence interval 3.3–26] for PP and 9.7 [95% confidence interval 3.2–29.6] for secondary prophylaxis). For PP females, the relative risk was 3.6 (95% confidence interval 1.3–9.5). ICD discharge-free survival for ventricular tachycardia/ventricular fibrillation ≥240 beats per minute was equivalent to the control survival rate. Ectopy (≥1000 premature ventricular complexes/24 hours) was the only independent clinical predictor of ICD discharge in males, and no predictor was identified in females. Conclusions— ICD therapy is indicated for PP in postpubertal males and in females ≥30 years with the p.S358L TMEM43 mutation. ICD termination of rapid ventricular tachycardia/ventricular fibrillation can reasonably be considered an aborted death.