The homozygous variant within the extended family leading to severe congenital heart defects was inherited from two parents, the heterozygous variant from one parent. This specific variant removes two base pairs from the gene, which results in early truncation and therefore a shorter protein. This shorter protein is likely unable to exert its function, which is repressing other genes in the heart. Some other heterozygous genetic variants have been determined as well, but more information is needed to establish their pathogenicity.
HEY2