USH1C and Down syndrome: 2016). Many mutations were novel, confirming that the genetic basis is often “private” and not detectable by screens that focus on previously reported mutations (Cremers et al. 2007). Repeatedly observed mutations, however, were common, not confined to but particularly in patients from MENA countries where the rate of parental consanguinity is high (Table 2). This indicates regional founder mutations that may guide the genetic diagnostic approach. Among the recurrent mutations are several large CNVs, including the 11p15‐p14 deletion syndrome that involves USH1C and ABCC8 in two KSA families.