Biallelic molecular defects in <i>MYBPC1</i> are associated with a lethal congenital form of myopathy (Lethal congenital contracture syndrome 4); meanwhile, heterozygous damaging variants lead to a form of distal arthrogryposis (distal arthrogryposis type 1B) and an early-onset congenital myopathy with tremor (congenital myopathy-16, CMYO16). The gene discussed is MYBPC1; the disease is distal arthrogryposis.