Transmembrane protein 67 (TMEM67), also known as Meckelin, encodes ciliary protein. It is likely implicated as a membrane receptor involved in signaling events during development and plays, with MKS1 gene, important roles in ciliogenesis, TMEM67 is most likely required for normal ciliary sensory signaling.
TMEM67 is expressed in all adult and fetal tissue with higher expression in embryonic adrenal gland, brain, kidney, lung and spinal cord. It localizes to primary cilia of the epithelial cells. Meckelin was predicted to contain a signal peptide, at least two cysteine-rich repeats, and a 490-residue extracellular region with four N-linked glycosylated sites, followed by seven transmembrane domains and a 30-residue cytoplasmic tail.
Mutations in the TMEM67 gene cause Meckel syndrome type 3. In addition, it was also identified that mutations in the TMEM67 gene occurred in patients affected with Joubert syndrome (JS), thus leading to define this gene as a sixth JS locus (JBTS6).