RESUMO
Background: Congenital heart disease (CHD) is the most common congenital anomaly. Up to 33% have an identifiable genetic etiology. Improved medical and surgical management of CHD has translated into longer life expectancy and a rapidly growing population of adults living with CHD. The adult CHD (ACHD) population did not have access during childhood to the genetic technologies available today and therefore have not had a robust genetic evaluation that is currently recommended for infants with CHD. Given this potential benefit; the aims of this study were to determine how ACHD cardiologists offer genetics services to patients and identify the indications that influence decision-making for genetics care. Methods: We performed a descriptive cross-sectional study of ACHD cardiologists. A study-developed questionnaire was distributed via emailed REDCap link. The recruitment email was sent to 104 potential respondents. The survey was open from 06/2022 to 01/2023. Results: Thirty-five cardiologists participated in the study (response rate of 34%). Most cardiologists identified as white (77%) and male (66%). Cardiologists were more likely to refer patients to genetics (91%) than to order testing themselves (57%). Of the testing ordered, chromosomal testing (55%) was ordered more than gene sequencing (14%). Most cardiologists would refer a patient with a conotruncal lesion (interrupted aortic arch) over other indications for a genetics evaluation. There were more reported barriers to ordering genetic testing (66%) compared to referring to genetics for a genetics evaluation (23%). Cardiologists were more confident recognizing features suggestive of a genetic syndrome than ordering the correct test (p = 0.001). Regarding associations between clinical factors and current practices, more years in practice trended towards less referrals and testing. Evaluating a greater number of patients (p = 0.11) and greater confidence recognizing syndromic features (p = 0.12) and ordering the correct test (p = 0.09) were all associated with ordering more testing. Conclusion: Testing for microdeletion syndromes is being offered and completed in the ACHD population, however testing for single-gene disorders associated with CHD is being under-utilized. Developing guidelines for genetic testing in adults with CHD could increase access to genetic services, impact medical management, reduce uncertainty regarding prognosis, and inform recurrence risk estimates.
RESUMO
BACKGROUND: Pathogenic variants in TTN cause a spectrum of autosomal dominant and recessive cardiovascular, skeletal muscle and cardioskeletal disease with symptom onset across the lifespan. The aim of this study was to characterise the genotypes and phenotypes in a cohort of TTN+paediatric patients. METHODS: Retrospective chart review was performed at four academic medical centres. Patients with pathogenic or truncating variant(s) in TTN and paediatric-onset cardiovascular and/or neuromuscular disease were eligible. RESULTS: 31 patients from 29 families were included. Seventeen patients had skeletal muscle disease, often with proximal weakness and joint contractures, with average symptom onset of 2.2 years. Creatine kinase levels were normal or mildly elevated; electrodiagnostic studies (9/11) and muscle biopsies (11/11) were myopathic. Variants were most commonly identified in the A-band (14/32) or I-band (13/32). Most variants were predicted to be frameshift truncating, nonsense or splice-site (25/32). Seventeen patients had cardiovascular disease (14 isolated cardiovascular, three cardioskeletal) with average symptom onset of 12.9 years. Twelve had dilated cardiomyopathy (four undergoing heart transplant), two presented with ventricular fibrillation arrest, one had restrictive cardiomyopathy and two had other types of arrhythmias. Variants commonly localised to the A-band (8/15) or I-band (6/15) and were predominately frameshift truncating, nonsense or splice-site (14/15). CONCLUSION: Our cohort demonstrates the genotype-phenotype spectrum of paediatric-onset titinopathies identified in clinical practice and highlights the risk of life-threatening cardiovascular complications. We show the difficulties of obtaining a molecular diagnosis, particularly in neuromuscular patients, and bring awareness to the complexities of genetic counselling in this population.