Martina Mia Mitić1, Dušan Ušjak1*, Maja Milošević2, Marija Cumbo1, Sofija Dunjić Manevski1, Branko Tomić1, Ivana Petrović2, Petar Otašević2, Slobodan Micović2, Milovan Bojić2, and Valentina Đorđević1
1Institute of Molecular Genetics and Genetic Engineering, Vojvode Stepe 444a, Belgrade, Serbia
2Institute for Cardiovascular Diseases Dedinje, Heroja Milana Tepića 1, Belgrade, Serbia
valentina [at] imgge.bg.ac.rs
Abstract
Normal aortic valve consists of three cusps that develop in the embryonic stage. Unicuspid aortic valve (UAV) is a rare congenital anomaly resulting in only one cusp with estimated prevalence of 0.02% in general population. Aim of this study was to identify genetic variants possibly associated with development of UAV. The study included 17 subjects, namely 5 UAV patients and their healthy family members without UAV disorder. Total DNA was isolated from venous blood samples and whole exomes sequencing (WES) was performed using BGI’s WES protocol. Adapter-trimmed and quality-filtered reads (fastp) were mapped to hg38 reference genome using BWA/SAMtools. VCF files were generated using GATK (BaseRecalibrator, HaplotypeCaller) and annotated with InterVar and AnnoVar tools. Rare heterozygous variants present in UAV patients were found in NOTCH1, TGFB2, MYH6, EGFR, FBN2, C1R, ROBO4 and TBX5, genes associated with development of aortic valves. Among these, most were missense mutations with damaging effects as predicted using in silico tools (SIFT and/or Polyphen). Only mutation in MYH6 p.Ala1130Ser was found in at least two different UAV patients. Also, rare homozygous missense mutation p.Gly577Ser with high damaging potential was found in ADAMTS5 gene. Besides, highly damaging heterozygous missense mutations were detected in gene interacting functional partners (STRING) of genes associated with development of aortic valves: DVL1, THBS1, NOTCH4, ADAMTS3, FBN1, NOTCH2, ADAM17, LRP5, WWTR1, C1S, ANKRD6 and TNNI1, as well as homozygous in ACAN and KNG1. Taken together, malfunctions in ADAMTS5, ACTA2, MYH6, FBN2, AXIN1, CELSR1 or TBX5 networks were found to be common in at least two UAV patients, suggesting existence of genetic basis in UAV disorder, possibly as a result of combined effects of multiple variants.
Keywords: unicuspid aortic valve, congenital heart disease, whole exome sequencing, genetic variants, valves
