Outcomes and experiences of genetic testing in children with congenital heart disease

Following genomic advances, genetic testing options for paediatric patients with congenital heart disease (CHD) have evolved significantly. A single-site audit was conducted to assess testing outcomes and a survey created to explore family experiences and preferences.

All genetic tests ordered in postcardiac surgery patients with CHD at The Children's Hospital at Westmead between January 2017 and December 2021 were reviewed. Diagnostic yield, clinical and demographic factors, and testing trends over time were evaluated. Surveys were sent to parents of children who had met a clinical geneticist (n=112).

Genetic testing was completed in 607 individuals (74 molecular testing; 533 cytogenetic testing only). The diagnostic rate was 36% and 9%, respectively. Use of molecular testing significantly increased over time (p=0.033), but yield did not (p=0.288). Molecular testing yield was high in neonates (64%), and patients with extracardiac anomalies (40%) or relevant family history (40%). Brain (p=0.022), haematological/cancer (p≤0.001), immune (p≤0.001), endocrine (p≤0.001) anomalies and intellectual disability (p=0.027) were associated with a diagnosis following cytogenetic testing. Short stature was significantly associated with diagnostic yield following molecular testing (p=0.012). Survey respondents (n=28) reported a positive experience (p=0.013) with minimal decisional regret (p=0.322).

Cytogenetic testing remains an important first-tier test in CHD. Furthermore, molecular testing guided by a clinical geneticist generates a high rate of genetic diagnoses. Parents of children with CHD value genetic testing with little regret.