The acronym COACH defines an autosomal recessive condition of Cerebellar vermis hypo/aplasia, Oligophrenia, congenital Ataxia, Coloboma and Hepatic fibrosis. Patients present the “molar tooth sign”, a midbrain-hindbrain malformation pathognomonic for Joubert Syndrome (JS) and Related Disorders (JSRDs). The main feature of COACH is congenital hepatic fibrosis (CHF), resulting from malformation of the embryonic ductal plate. CHF is invariably found also in Meckel syndrome (MS), a lethal ciliopathy already found to be allelic with JSRDs at the CEP290 and RPGRIP1L genes. Recently, mutations in the MKS3 gene (approved symbol TMEM67), causative of about 7% MS cases, have been detected in few Meckel-like and pure JS patients. Analysis of MKS3 in 14. COACH families identified mutations in 8 (57%). Features such as colobomas and nephronophthisis were found only in a subset of mutated cases. These data confirm COACH as a distinct JSRD subgroup with core features of JS plus CHF, which major gene is MKS3, and further strengthen gene-phenotype correlates in JSRDs.

Original languageEnglish
Pages (from-to)E432-E442
JournalHuman Mutation
Issue number2
StatePublished - Feb 2009


FundersFunder number
Italian Ministry of Health
National Institutes of Health2006, GGP08145
National Institute of Neurological Disorders and StrokeR01NS048453
Burroughs Wellcome Fund
March of Dimes Foundation
Fondazione Telethon
Ministero dell’Istruzione, dell’Università e della Ricerca


    • COACH syndrome
    • Congenital hepatic fibrosis
    • Joubert syndrome and related disorders
    • MKS3
    • TMEM67


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