Chromosomal abnormalities and copy number variations in fetal left sided congenital heart defects

Objectives: To demonstrate the spectrum of copy number variants (CNVs) in fetuses with isolated left sided congenital heart defects (CHDs), and analyze genetic content. Methods: Between 2003 and 2012, 200 fetuses were identified with left sided CHD. Exclusion criteria were chromosomal rearrangements, 22q11.2 microdeletion and/or extra-cardiac malformations (n=64). We included cases with additional minor anomalies (n=39), such as single umbilical artery. In 54 of 136 eligible cases, stored material was available for array analysis. CNVs were categorized as either (likely) benign, (likely) pathogenic or of unknown significance. Results: In 18 of the 54 isolated left sided CHDs we found 28 rare CNVs (prevalence 33%, average 1.6 CNV per person size 10.6kb – 2.2Mb). Our interpretation yielded clinically significant CNVs in 2 of 54 cases (4%) and variants of unknown significance in 3 other cases (6%). Conclusions: In left sided CHDs that appear isolated, with normal chromosome analysis and 22q11.2 FISH analysis, array analysis detects clinically significant CNVs. When counselling parents of a fetus with a left sided CHD it must be taken into consideration that aside from the cardiac characteristics, the presence of extra-cardiac malformations and chromosomal abnormalities influence the treatment plan and prognosis.