ICD-10 Q04.3 | OMIM 216360 | |
COACH syndrome is a rare autosomal recessive disorder characterised by Cerebellar vermis hypoplasia, Oligophrenia (developmental delay/mental retardation), Ataxia, Coloboma, and Hepatic fibrosis. The vermis hypoplasia falls in a spectrum of mid-hindbrain malformation called the molar tooth sign (MTS), making COACH a Joubert syndrome related disorder (JSRD) due to mutation in the gene TMEM67 in majority of cases. Renal insufficiency was also found in some cases.
Contents
Liver Biopsy
Congenital Hepatic Fibrosis (CHF) is hallmark of COACH syndrome. Multiple hepatic tumors has also been reported in some cases. Septal fibrosis and pseudolobules, inflammatory infiltrates, signs of cholestasis, and reduced numbers of intrahepatic bile ducts progresses to live cirrhosis.
Renal Biopsy
Showed mild interstitial fibrosis and amyloid deposit, but had no functional impairment.
Clinical Features
Neurologic abnormalities are the first symptoms in most cases. Hypotonia in infancy with later development of ataxia, developmental delay/mental retardation, abnormal breathing pattern (tachypnoea and/or apnoea) and abnormal eye movements (typically, nystagmus, oculomotor apraxia (OMA) or difficulty with smooth visual pursuit).
Other features variably reported in JSRD include dysmorphic facial features, polydactyly, retinal dystrophy, chorioretinal colobomas, renal disease (cysts or juvenile nephronophthisis), hepatic fibrosis, and tongue papules or oral frenulae.
The majority of cases were diagnosed late in childhood or adolescence. Complications of the hepatopathy contribute extensively to the morbidity and lethality in the course of the disease. Major complications are portal hypertension, esophageal varices, and gastrointestinal bleeding.
CT Brain
Cerebellar vermis hypoplasia can be seen.
MRI Brain
Cogenital Vermian Hypoplasia (CVH) in COACH syndrome was accompanied by elongation of the superior cerebellar peduncles and a deep interpeduncular fossa, all features that constitute the molar tooth sign (MTS), the key feature of Joubert syndrome and related disorders (JSRD).
CT Abdomen
Hepatospleenomegaly with portal hypertension.
Treatment
Successful liver and kidney transplantation have been done in some cases.