Identification of 22q11.2 deletion in patients from adult congenital heart disease clinic: a missed burden in the transition care in Hong Kong

Abstract

22q11.2 deletion syndrome (22q11DS) is a common genetic diagnosis in patients with congenital heart disease (CHD). It is multi-systemic with both congenital and later-onset features with lifelong consequences. Variable clinical expression and limited awareness contribute to its under-diagnosis. With low childhood mortality, there is an increasing number of diagnosed/undiagnosed adults, posing a hidden challenge in the transition care for patients with CHD. Our objective is to determine the prevalence of 22q11DS in adult patients with conotruncal defects and to delineate their extra-cardiac manifestations. We enrolled patients through an adult CHD clinic by active screening, using fluorescence-PCR and FISH. We have recruited 156 with conotruncal defects in 2012-2013(on-going recruitment). Results: Eighteen patients are diagnosed with 22q11DS, which translates into a missed diagnosis of 1 in every 10 adults with conotruncal defects. Eleven had the cardiac diagnosis of tetralogy, 6 had pulmonary atresia and ventricular septal defect, 1 had interrupted aortic arch. Our approach of screening by molecular testing has increased the detection rate of 22q11.2DS by at least 4 times.Screening by cardiologists using dysmorphology assessment only may miss 40 percent of patients. Our cohort of patients with 22q11.2DS previously undiagnosed have less extra-cardiac manifestations that the other reported series, presumably due to lack of medical surveillance appropriate for patients with 22q11.2DS.Conclusion: This study will provide important information on the disease burden of 22q11DS and may highlight an important and actionable gap in the transitional care of patients with CHD.