Long-Term Follow-Up Study on the Uptake of Genetic Counseling and Predictive DNA Testing in Inherited Cardiac Conditions

BACKGROUND: Inherited cardiac conditions present with a wide range of symptoms and may even result in sudden cardiac death. Relatives of probands with a confirmed pathogenic genetic variant are advised predictive DNA testing to enable prevention and treatment. In 2 previous cohort studies of 115 probands with a pathogenic variant, family uptake of genetic counseling was assessed in the first year(s) after test result disclosure to the proband. This study assesses uptake in these cohorts in the 14 to 23 years following disclosure. METHODS: Uptake was determined retrospectively using patient records. First-degree relatives, and second-degree relatives of a deceased first-degree relative suspected of having an inherited cardiac condition, were considered eligible. RESULTS: Of 717 eligible relatives (598 first-degree and 119 second-degree relatives), 60% attended genetic counseling. Most of them (68.6%) attended genetic counseling in the first year. A total of 98.4% of counseled relatives pursued predictive DNA testing. A total of 49.2% was identified as carrier. Median time between disclosure to the proband and counseling of relatives was 6 months (range: 0-187 months). Attending genetic counseling was observed more frequently in first-degree relatives, female relatives, primary arrhythmia syndromes, relatives with manifest inherited cardiac condition, relatives without children and families with sudden cardiac death in first-degree relatives <40 years. CONCLUSIONS: During median follow-up of 16 years, 60.0% of relatives attended genetic counseling, with 41.0% in the first year. Our results may suggest that some relatives are not or inadequately informed or that barriers against genetic counseling are present. Further research is needed into interventions facilitating family communication, increasing awareness among families and healthcare professionals, and lowering thresholds for genetic counseling

Long-term follow-up study on the uptake of genetic counseling and predictive DNA testing in inherited cardiac conditions

BACKGROUND: Inherited cardiac conditions present with a wide range of symptoms and may even result in sudden cardiac death. Relatives of probands with a confirmed pathogenic genetic variant are advised predictive DNA testing to enable prevention and treatment. In 2 previous cohort studies of 115 probands with a pathogenic variant, family uptake of genetic counseling was assessed in the first year(s) after test result disclosure to the proband. This study assesses uptake in these cohorts in the 14 to 23 years following disclosure. METHODS: Uptake was determined retrospectively using patient records. First-degree relatives, and second-degree relatives of a deceased first-degree relative suspected of having an inherited cardiac condition, were considered eligible. RESULTS: Of 717 eligible relatives (598 first-degree and 119 second-degree relatives), 60% attended genetic counseling. Most of them (68.6%) attended genetic counseling in the first year. A total of 98.4% of counseled relatives pursued predictive DNA testing. A total of 49.2% was identified as carrier. Median time between disclosure to the proband and counseling of relatives was 6 months (range: 0-187 months). Attending genetic counseling was observed more frequently in first-degree relatives, female relatives, primary arrhythmia syndromes, relatives with manifest inherited cardiac condition, relatives without children and families with sudden cardiac death in first-degree relatives <40 years. CONCLUSIONS: During median follow-up of 16 years, 60.0% of relatives attended genetic counseling, with 41.0% in the first year. Our results may suggest that some relatives are not or inadequately informed or that barriers against genetic counseling are present. Further research is needed into interventions facilitating family communication, increasing awareness among families and healthcare professionals, and lowering thresholds for genetic counseling

KBTBD13 is a novel cardiomyopathy gene

KBTBD13 variants cause nemaline myopathy type 6 (NEM6). The majority of NEM6 patients harbors the Dutch founder variant, c.1222C>T, p.Arg408Cys (KBTBD13 p.R408C). Although KBTBD13 is expressed in cardiac muscle, cardiac involvement in NEM6 is unknown. Here, we constructed pedigrees of three families with the KBTBD13 p.R408C variant. In 65 evaluated patients, 12% presented with left ventricle dilatation, 29% with left ventricular ejection fraction< 50%, 8% with atrial fibrillation, 9% with ventricular tachycardia, and 20% with repolarization abnormalities. Five patients received an implantable cardioverter defibrillator, three cases of sudden cardiac death were reported. Linkage analysis confirmed cosegregation of the KBTBD13 p.R408C variant with the cardiac phenotype. Mouse studies revealed that (1) mice harboring the Kbtbd13 p.R408C variant display mild diastolic dysfunction; (2) Kbtbd13-deficient mice have systolic dysfunction. Hence, (1) KBTBD13 is associated with cardiac dysfunction and cardiomyopathy; (2) KBTBD13 should be added to the cardiomyopathy gene panel; (3) NEM6 patients should be referred to the cardiologist

KBTBD13 is a novel cardiomyopathy gene

KBTBD13 variants cause nemaline myopathy type 6 (NEM6). The majority of NEM6 patients harbors the Dutch founder variant, c.1222C>T, p.Arg408Cys (KBTBD13 p.R408C). Although KBTBD13 is expressed in cardiac muscle, cardiac involvement in NEM6 is unknown. Here, we constructed pedigrees of three families with the KBTBD13 p.R408C variant. In 65 evaluated patients, 12% presented with left ventricle dilatation, 29% with left ventricular ejection fraction< 50%, 8% with atrial fibrillation, 9% with ventricular tachycardia, and 20% with repolarization abnormalities. Five patients received an implantable cardioverter defibrillator, three cases of sudden cardiac death were reported. Linkage analysis confirmed cosegregation of the KBTBD13 p.R408C variant with the cardiac phenotype. Mouse studies revealed that (1) mice harboring the Kbtbd13 p.R408C variant display mild diastolic dysfunction; (2) Kbtbd13-deficient mice have systolic dysfunction. Hence, (1) KBTBD13 is associated with cardiac dysfunction and cardiomyopathy; (2) KBTBD13 should be added to the cardiomyopathy gene panel; (3) NEM6 patients should be referred to the cardiologist

KBTBD13 is a novel cardiomyopathy gene

KBTBD13 variants cause nemaline myopathy type 6 (NEM6). The majority of NEM6 patients harbors the Dutch founder variant, c.1222C>T, p.Arg408Cys (KBTBD13 p.R408C). Although KBTBD13 is expressed in cardiac muscle, cardiac involvement in NEM6 is unknown. Here, we constructed pedigrees of three families with the KBTBD13 p.R408C variant. In 65 evaluated patients, 12% presented with left ventricle dilatation, 29% with left ventricular ejection fraction< 50%, 8% with atrial fibrillation, 9% with ventricular tachycardia, and 20% with repolarization abnormalities. Five patients received an implantable cardioverter defibrillator, three cases of sudden cardiac death were reported. Linkage analysis confirmed cosegregation of the KBTBD13 p.R408C variant with the cardiac phenotype. Mouse studies revealed that (1) mice harboring the Kbtbd13 p.R408C variant display mild diastolic dysfunction; (2) Kbtbd13-deficient mice have systolic dysfunction. Hence, (1) KBTBD13 is associated with cardiac dysfunction and cardiomyopathy; (2) KBTBD13 should be added to the cardiomyopathy gene panel; (3) NEM6 patients should be referred to the cardiologist