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COACH syndrome

Dr Jeremy Jones and Dr Frank Gaillard et al.

The acronym COACH describes a syndrome associated with:

C - cerebellar vermis defect (Joubert syndrome)
O - oligophrenia
A - ataxia
C - coloboma
H - hepatic fibrosis

Epidemiology

There only as little as 11 cases having been reported in the English medical literature.

Associations

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

Clinical presentation

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

Pathology

Aetiology

Presently, no genes have been identified that cause COACH syndrome specifically. It is likely that alterations in multiple genes cause this condition.

Radiographic features

Ultrasound

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.

CT-MRI

Absence or hypoplasia of the vermis ; the cerebellar hemispheres appose one another because of the lack of the vermis ; the superior cerebellar peduncules 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.

Treatment and prognosis

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