Consistent with this notion, heterozygous carriers of the MYBPC1 NM_002465.3 c.952C>T (p.R318*) nonsense mutation, residing in the NH2-terminal Ig C2 domain and resulting in partial loss of sMyBP-C, are asymptomatic, while homozygous carriers develop Lethal Congenital Contractural Syndrome-4 (LCCS-4), exhibiting perinatal lethality (33). Here, MYBPC1 is linked to lethal congenital contracture syndrome 4.