Background: Danon disease is a rare but serious cardiac and skeletal myopathy leading to substantial morbidity and early mortality due to arrhythmia and cardiomyopathy. The X-linked nature of inheritance accounts for reported differences in phenotypic severity between men and women. The rarity of Danon disease has limited understanding of the complete phenotype. Clinical estimates of ages of disease onset and survival based on gender have not been published. Methods and Results: We present data on 82 patients with Danon disease from 36 families, the largest series to date. Men were severely affected with cognitive disabilities (100%), hypertrophic cardiomyopathy (88%), and muscle weakness (80%). Men had a high morbidity and were unlikely to reach the age of 25 years without a cardiac transplantation. Women were less severely affected but reported higher than expected levels of cognitive (47%) and skeletal muscle complaints (50%) and manifesting an equal prevalence of dilated cardiomyopathy and hypertrophic cardiomyopathy. Combining our data with that of 63 other Danon disease case reports in the literature, the average ages of first symptom, cardiac transplantation, and death were 12.1, 17.9, and 19.0 years in men and 27.9, 33.7, and 34.6 years in women, respectively. Conclusion: These data more broadly illuminate the Danon disease phenotype and should prove useful to physicians working with and providing genetic counseling to families with Danon disease. Women with Danon disease present with clinical symptoms and events approximately 15 years after men and report a higher proportion of cognitive and skeletal muscle problems than previously recognized. Genet Med 2011:13(6):563-568.

Background: Filamin C truncating variants ( FLNCtv ) cause a form of arrhythmogenic cardiomyopathy (ACM): the mode of presentation, natural history and risk stratification of FLNCtv remain incompletely explored. We sought to develop a risk profile for refractory heart failure and life-threatening arrhythmias in a multicenter cohort of FLNCtv carriers. Methods: FLNCtv carriers were identified from ten tertiary care centers for genetic cardiomyopathies. Clinical and outcome data were compiled. Composite outcomes were all-cause mortality/heart transplantation/left ventricle assist device (D/HT/LVAD), non-arrhythmic death/HT/LVAD and SCD/major ventricular arrhythmias (SCD/MVA). Previously established cohorts of 46 patients with LMNA and 60 with DSP -related ACM were used for prognostic comparison. Results: Eighty-five patients carrying FLNCtv were included (42±15 years, 53% males, 45% probands). Phenotypes were heterogeneous at presentation: 49% dilated cardiomyopathy, 25% arrhythmogenic left dominant cardiomyopathy, 3% arrhythmogenic right ventricular cardiomyopathy. Left ventricular ejection fraction (LVEF) was <50% in 64% of carriers and 34% had right ventricular fractional area changes (RVFAC=(right ventricular end-diastolic area - right ventricular end-systolic area)/ right ventricular end-diastolic area) <35%. During follow-up (median time 61 months), 19 (22%) carriers experienced D/HT/LVAD, 13 (15%) non-arrhythmic death/HT/LVAD and 23 (27%) SCD/MVA. The SCD/MVA incidence of FLNCtv carriers did not significantly differ from LMNA carriers and DSP carriers. In FLNCtv carriers, LVEF was associated with the risk of D/HT/LVAD and non-arrhythmic death/HT/LVAD. C Conclusions: Among patients referred to tertiary referral centers, FLNCtv ACM is phenotypically heterogeneous and characterized by high risk of life-threatening arrhythmias, which does not seem to be associated with the severity of LV dysfunction.

ilated cardiomyopathy (DCM) is a nonischemic, nontoxic, noninfectious, or nonvalvular heart muscle disease characterized by left ventricular or biventricular systolic dysfunction. 1,2 Typical onset of the disease is in the fourth or fifth decade of life and it affects predominantly male individuals with a male-to-female ratio of 3:1. 2 Although a specific cause might be unknown in a non-negligible number of patients, to date, more than one-third of familial forms and approximately 25% of sporadic cases have positive genetic testing for pathogenic (P) or likely pathogenic (LP) variants. [3][4][5][6] Recent evidence highlights the importance of specific genotypes in determining the prognosis of patients with DCM, either alone or in combination with environmental factors. [7][8][9][10][11] Contemporary analyses highlight that DCM is increasingly diagnosed in older patients 12 and a late-onset (ie, age >60 years) form of DCM could differ from more typical-onset DCM presentations. 13 However, the genetic background and the prognostic impact of genetic characterization among patients with DCM presenting who are older than 60 years are largely unknown.The aim of the present study was to investigate the genetic background and the natural history of a large international cohort of individuals with DCM presenting in individuals older than 60 years to assess the importance of genetic testing in those patients. Methods Study PopulationFor the present study, we included all consecutive patients with DCM older than 60 years at the time of diagnosis (ie, lateonset DCM), with available genetic testing analysis, from 7 international tertiary centers worldwide: Cardiovascular IMPORTANCE Dilated cardiomyopathy (DCM) is frequently caused by genetic factors. Studies identifying deleterious rare variants have predominantly focused on early-onset cases, and little is known about the genetic underpinnings of the growing numbers of patients with DCM who are diagnosed when they are older than 60 years (ie, late-onset DCM).OBJECTIVE To investigate the prevalence, type, and prognostic impact of disease-associated rare variants in patients with late-onset DCM. DESIGN, SETTING, AND PARTICIPANTSA population of patients with late-onset DCM who had undergone genetic testing in 7 international tertiary referral centers worldwide were enrolled from March 1990 to August 2020. A positive genotype was defined as the presence of pathogenic or likely pathogenic (P/LP) variants. MAIN OUTCOMES AND MEASURESThe study outcome was all-cause mortality.RESULTS A total of 184 patients older than 60 years (103 female [56%]; mean [SD] age, 67 [6] years; mean [SD] left ventricular ejection fraction, 32% [10%]) were studied. Sixty-six patients (36%) were carriers of a P/LP variant. Titin-truncating variants were the most prevalent (present in 46 [25%] of the total population and accounting for 46 [69%] of all genotype-positive patients). During a median (interquartile range) follow-up of 42 (10-115) months, 23 patients (13%) died; 17 (25%) of these were carriers o...

Introduction-Danon disease is a rare X-linked myopathy that is characterized clinically by a triad of cardiomyopathy, skeletal myopathy and cognitive impairment. The purpose of this investigation was to quantify functional performance, muscle weakness and quadriceps activation in individuals with Danon disease as compared to healthy individuals.

Purpose: Array comparative genomic hybridization is now a widely used clinical tool for the evaluation of intellectual disability. The current 10% yield of positive findings is based largely on pediatric data. Adults with unexplained intellectual disability have not been systematically studied with array comparative genomic hybridization. Here, we report our initial experience with array comparative genomic hybridization testing on 45 adults with unexplained intellectual disability referred to an adult genetics clinic. Methods: Beginning in 2006, we applied clinically available array comparative genomic hybridization testing to adults referred with an intellectual disability phenotype. The initial platform used was an early generation targeted or constitutional array, which was replaced by our current platform using more than 5000 bacterial artificial chromosome clones with an average resolution of 500 Kb and targeting 114 disease loci. All patients also underwent highresolution karyotype analysis and molecular testing for Fragile X syndrome. Results: Our population comprised 45 patients with unexplained intellectual disability (18 men and 27 women) with an average age of 35.1 years. Most patients had not been evaluated by genetics clinics since childhood or had never undergone a genetic evaluation; only two had documentation of prior normal karyotype studies. Three subjects had abnormal high-resolution chromosome studies, which were also confirmed by array comparative genomic hybridization. Seven of the remaining 42 patients (17%) had novel genomic losses identified only by array comparative genomic hybridization. Conclusion: Abnormal genomic losses detected by array comparative genomic hybridization are prevalent in adults with unexplained intellectual disability. Our data showing abnormalities in 22% and 17% of overall patients and of cases with normal karyotypes, respectively, suggest that the yield of array comparative genomic hybridization in adults with unexplained intellectual disability may be higher than in pediatric populations. Genet Med 2010:12(1):32-38.

Precision medicine initiatives across the globe have led to a revolution of repositories linking large-scale genomic data with electronic health records, enabling genomic analyses across the entire phenome. Many of these initiatives focus solely on research insights, leading to limited direct benefit to patients. We describe the Biobank at the Colorado Center for Personalized Medicine (CCPM Biobank) that was jointly developed by the University of Colorado Anschutz Medical Campus and UCHealth to serve as a unique, dual-purpose research and clinical resource accelerating personalized medicine. This living resource currently has over 200,000 patients with ongoing recruitment. We highlight the clinical, laboratory, regulatory, and HIPAA-compliant informatics infrastructure along with our stakeholder engagement, consent, recontact, and participant engagement strategies. We characterize aspects of genetic and geographic diversity unique to the Rocky Mountain Region, the primary catchment area for CCPM Biobank participants. We leverage linked health and demographic information of the CCPM Biobank participant population to demonstrate the utility of the CCPM Biobank to replicate complex trait associations in the first 33,674 genotyped patients across multiple disease domains. Finally, we describe our current efforts towards return of clinical genetic test results including high-impact pathogenic variants and pharmacogenetic information, and our broader goals as the CCPM Biobank continues to grow. Bringing clinical and research interests together fosters unique clinical and translational questions that can be addressed from the large EHR-linked CCPM Biobank resource within a HIPAA and CLIA-certified environment.

Barth syndrome is an X-linked genetic condition featuring neutropenia, skeletal myopathy, and dilated cardiomyopathy in boys due to tafazzin (TAZ) mutations. Pure dilated cardiomyopathy without other features of Barth syndrome may also result from TAZ mutations and survival into adulthood has been described. Although TAZ testing is routinely included in dilated cardiomyopathy panels in adults, the prevalence of TAZ mutations in the adult population, including women who may be at risk to develop later onset disease due to TAZ mutations, has not been measured. We screened 292 families with dilated cardiomyopathy (209 male and 83 female probands) for TAZ mutations using denaturing high-performance liquid chromatography and sequence analysis. Putative mutations were evaluated based on standard criteria including screening available relatives and healthy controls and for effects on splicing efficiency in the case of one intronic variant. Two variants suspicious for being pathogenic were found in two unrelated families (c.387T>C, Phe128Ser and c.507C>T, Leu169Leu). The Phe128Ser variant had been previously reported as a pathogenic mutation; however we determined that this variant is instead a rare polymorphism restricted to African Americans. The Leu169Leu variant was detected in a male patient and altered RNA processing in our minigene assay supporting a pathogenic role. No mutations in female subjects were detected. Tafazzin mutations were rare in our population of adults with dilated cardiomyopathy and none were found in females. Our findings indicate that genetic testing for tafazzin should not be routinely performed in dilated cardiomyopathy as suggested by current guidelines. Furthermore, the Phe128Ser variant is not pathogenic, but likely represents a benign polymorphism in persons of African American ancestry

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