Autosomal recessive lethal congenital contractural syndrome type 4 (LCCS4) caused by a mutation in MYBPC1

Autosomal recessive lethal congenital contractural syndrome (LCCS) is a severe form of neuromuscular arthrogryposis. We previously showed that this phenotype is caused in two unrelated inbred Bedouin tribes by different defects in the phosphatidylinositol pathway. However, the molecular basis of the same phenotype in other tribes remained elusive. Whole exome sequencing identified a novel LCCS founder mutation within a minimal shared homozygosity locus of approximately 1Mb in two affected individuals of different tribes: a homozygous premature stop producing mutation in MYBPC1, encoding myosin-binding protein C, slow type. A dominant missense mutation in MYBPC1 was previously shown to cause mild distal arthrogryposis. We now show that a recessive mutation abrogating all functional domains in the same gene leads to LCCS.