Meckel syndrome (MKS) is an embryonic lethal, autosomal recessive disorder characterized by polycystic kidney disease, central nervous system defects, polydactyly and liver fibrosis. B9D1 is a B9 domain-containing protein, one of several that are involved in ciliogenesis. Alterations in expression of this gene have been found in a family with Meckel syndrome. B9D1, and its related protein B9D2, form a complex with MKS1, disruption of which causes MKS. B9D1 is thought to be required for normal hedgehog signaling, ciliogenesis, and ciliary protein localization .Synonyms: B9 domain-containing protein 1, EPPB9