Sambharia M, Freese ME, Donato F, Bathla G, Abukhiran IMM, Dantuma MI, Mansilla MA, Thomas CP. Suspected Autosomal Recessive Polycystic Kidney Disease but Cerebellar Vermis Hypoplasia, Oligophrenia Ataxia, Coloboma, and Hepatic Fibrosis (COACH) Syndrome in Retrospect, A Delayed Diagnosis Aided by Genotyping and Reverse Phenotyping: A Case Report and A Review of the Literature. Nephron. 2023 Jan 6:1-9. doi: 10.1159/000527991. Epub ahead of print. PMID: 36617405.
Abstract
The clinical features of cerebellar vermis hypoplasia, oligophrenia, ataxia, coloboma, and hepatic fibrosis (COACH) characterize the rare autosomal recessive multisystem disorder called COACH syndrome. COACH syndrome belongs to the spectrum of Joubert syndrome and related disorders (JSRDs) and liver involvement distinguishes COACH syndrome from the rest of the JSRD spectrum. Developmental delay and oculomotor apraxia occur early but with time, these can improve and may not be readily apparent or no longer need active medical management. Congenital hepatic fibrosis and renal disease, on the other hand, may develop late, and the temporal incongruity in organ system involvement may delay the recognition of COACH syndrome. We present a case of a young adult presenting late to a Renal Genetics Clinic for evaluation of renal cystic disease with congenital hepatic fibrosis, clinically suspected to have autosomal recessive polycystic kidney disease. Following genetic testing, a reevaluation of his medical records from infancy, together with reverse phenotyping and genetic phasing, led to a diagnosis of COACH syndrome.
George A, Cogliati T, Brooks BP. Genetics of syndromic ocular coloboma: CHARGE and COACH syndromes. Exp Eye Res. 2020 Apr;193:107940. doi: 10.1016/j.exer.2020.107940. Epub 2020 Feb 4. PMID: 32032630; PMCID: PMC7310839.
Abstract
Optic fissure closure defects result in uveal coloboma, a potentially blinding condition affecting between 0.5 and 2.6 per 10,000 births that may cause up to 10% of childhood blindness. Uveal coloboma is on a phenotypic continuum with microphthalmia (small eye) and anophthalmia (primordial/no ocular tissue), the so-called MAC spectrum. This review gives a brief overview of the developmental biology behind coloboma and its clinical presentation/spectrum. Special attention will be given to two prominent, syndromic forms of coloboma, namely, CHARGE (Coloboma, Heart defect, Atresia choanae, Retarded growth and development, Genital hypoplasia, and Ear anomalies/deafness) and COACH (Cerebellar vermis hypoplasia, Oligophrenia, Ataxia, Coloboma, and Hepatic fibrosis) syndromes. Approaches employed to identify genes involved in optic fissure closure in animal models and recent advances in live imaging of zebrafish eye development are also discussed.
Sanjeev RK, Kapoor S, Goyal M, Kapur R, Gleeson JG. Molar Tooth Sign with Deranged Liver Function Tests: An Indian Case with COACH Syndrome. Case Rep Pediatr. 2015;2015:385910. doi: 10.1155/2015/385910. Epub 2015 May 17. PMID: 26075130; PMCID: PMC4449927.
Abstract
We report the first genetically proven case of COACH syndrome from the Indian subcontinent in a 6-year-old girl who presented with typical features of Joubert syndrome along with hepatic involvement. Mutation analysis revealed compound heterozygous missense mutation in the known gene TMEM67 (also called MKS3).
Brancati F, Iannicelli M, Travaglini L, Mazzotta A, Bertini E, Boltshauser E, D'Arrigo S, Emma F, Fazzi E, Gallizzi R, Gentile M, Loncarevic D, Mejaski-Bosnjak V, Pantaleoni C, Rigoli L, Salpietro CD, Signorini S, Stringini GR, Verloes A, Zabloka D, Dallapiccola B, Gleeson JG, Valente EM; International JSRD Study Group. MKS3/TMEM67 mutations are a major cause of COACH Syndrome, a Joubert Syndrome related disorder with liver involvement. Hum Mutat. 2009 Feb;30(2):E432-42. doi: 10.1002/humu.20924. PMID: 19058225; PMCID: PMC2635428.
Abstract
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.
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