COACH syndrome

Last revised by Rohit Sharma on 11 Jul 2022

The acronym COACH describes a syndrome associated with:

COACH syndrome is considered extremely rare.

The association with infantile polycystic kidney disease or Potter type I is well established. 

  • delayed psychomotor development
  • visual difficulty
  • hepatomegaly, elevated levels of liver enzymes (hepatic fibrosis)
  • cerebellar ataxia
  • dysmorphic features such as hypertelorism and ptosis
  • episodic hyperpnea

Inherited in an autosomal recessive pattern, multiple implicated gene mutations have been identified as causative, including in the MKS3CC2D2A, and RPGRIP1L genes 4.

  • increased echogenicity of the liver parenchyma, collateral vessels and splenomegaly due to portal hypertension
  • increased echogenicity of the kidneys' pyramids
  • the sonographic features of eye coloboma include a defect in the retina with an obliquely posterior herniation of the vitreus body; retinal detachment
  • absence or hypoplasia of the vermis: the cerebellar hemispheres appose each other due to the absence of the vermis; the superior cerebellar peduncles are prominent because they have a horizontal course and are well delineated by CSF
  • may show evidence of hepatic fibrosis and portal hypertension 
  • may show evidence of polycystic kidney disease
  • may show chorioretinal colobomas

The main clinical problem for patients with COACH syndrome is progressive portal hypertension and liver failure. Treatment aims to reduce symptoms and prevent complications.

The lack of oculomotor abnormalities and the episodic hyperpnea distinguish this syndrome from Joubert syndrome.

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