Additionally, extended and complex MD phenotypes including cavernous cerebral malformations, hearing loss, and dysmorphisms may be the result of the fact that SGCE is sometimes deleted together with neighboring genes including COL1A2 encoding the collagen alpha-2(1) chain reflecting haploinsufficiency of both SGCE and COL1A2 (32). Here, COL1A2 is linked to famililal cerebral cavernous malformations.