Rare Copy Number Variation Analysis in Chinese Children of Complete Atrioventricular Canal and Single Ventricle 

Abstract

Background: Congenital heart disease (CHD) is the most common birth defects. Copy number variations (CNVs) have been proved to be important genetic factors that contribute to CHD. Here, we screened pathogenic CNVs in Chinese children with two rare types of CHD, complete atrioventricular canal (CAVC) and single ventricle (SV) .Methods：We screened CNVs in 262 sporadic CAVC cases and 259 sporadic SV cases respectively, using a customized SNP array. The detected CNVs were annotated and filtered using available databases.Results: Among 262 CAVC patients, we identified 44 rare CNVs in 43 individuals (16.4 %, 43/262), including 2 syndrome-related CNVs (7q11.23 and 8q24.3 deletion). Surprisingly, 88.6% rare CNVs (39/44) were duplications of 21q11.2-21q22.3, which were categorized as trisomy 21 (Down syndrome, DS). In CAVC with DS patients, the female to male ratio was 1.6:1 (24:15), and the rate of pulmonary hypertension (PH) was 41% (16/39). Additionally, 6 rare CNVs were identified in the SV patients (2.3%, 6/259), and none of them was trisomy 21.Conclusions: Our study identified 50 rare CNVs in 262 CAVC and 259 SV patients, representing the largest cohort of these two rare CHD types in Chinese population. The results provided strong correlation between CAVC and DS, which also showed sex difference and higher incidence of PH. The presence of rare CNVs suggests the etiology of complex CHD is incredibly diverse, and CHD candidate genes remain to be discovered.