This is a salient feature of PTA, which is a hallmark of several human congenital heart diseases, including DiGeorge syndrome (also known as del22q11).28 DiGeorge syndrome results from heterozygous deletions within human chromosome 22q11, and it is of interest for this study that one of the genes most strongly involved in these deletions is v-crk sarcoma virus CT10 oncogene homolog (avian)-like (CrkL), closely related to Crk, which is known to associate with p130Cas (Cas denotes Crk-associated substrate). The gene discussed is CRKL; the disease is 22q11.2 deletion syndrome.