Meckel syndrome, type 6 (MKS6) is a severe congenital disorder defined by the presence of occipital encephalocele, cystic dysplasia of the kidneys, hepatic fibrosis and bile duct proliferation, and postaxial polydactyly of the hands and feet. Other symptoms may include a cleft palate and club feet. The prognosis of the disorder remains poor, with most cases resulting in in-utero or perinatal death. The disorder has been seen to be more prevalent in Finnish, Belgian, Gujarati Indian and Kuwaiti Bedouin populations.
MKS6 follows an autosomal recessive pattern of inheritance. It is caused by mutations in the CC2D2A gene, which encodes a ciliary protein that helps prevent the diffusion of transmembrane proteins between the cilia and plasma membranes. The CC2D2A protein is also predicted to be involved in primary cilium assembly, determination of left/right symmetry and embryonic brain development.