Retrospective Review of Genetic Conditions in Patients with Congenital Heart Defects Attending a Quaternary Paediatric Cardiology Service in Johannesburg, South Africa

Abstract

Congenital heart defects (CHDs) are the most common major birth defects, with an estimated incidence of 6 per 1000 livebirths. The causes of CHDs remain poorly understood. Genetic and environmental factors are known to contribute. The study aimed to retrospectively review patients with CHDs attending a cardiology service for confirmed genetic conditions. A review of 181 clinical records of children (0 months to 18 years) seen between 1 January 2019 – 31 December 2019 was conducted. Genetic testing was performed on 58/181 (32%) patients and 29/181 (16%) were confirmed to have a genetic syndrome. Trisomy 21 was the predominant chromosomal aneuploidy and 22q11.2 deletion the predominant copy number variant detected. Single gene causes and other chromosomal copy number variants were underrepresented due to unavailability or non-requisition of tests. We recommend routine, multidisciplinary genetic assessment of patients with CHDs with expanded genetic testing to improve diagnostic rates, direct management and optimize outcomes.