= hepatolenticular degeneration. Autosomal recessive condition with copper accumulation due to impairment of biliary excretion. Leads to cirrhosis, via a stage indistinguishable from chronic active hepatitis, plus neurological disease. Caused by mutations of the ATP7B gene that codes for a copper transporting ATPase – over 300 mutations known, varying geographically.
Usually presents in late teens but has been described as young as 3yrs. Neurological presentation tends to be older (by 5 years) although they usually have subclinical liver disease. Hepatic disease varies from elevated aminotransferases, through chronic liver disease to fulminant hepatic failure (often with Coombs negative haemolytic anaemia), about 5% of presentations.
Basal ganglia involvement leads to movement disorders viz:
- Gait disturbances
Other neurological signs are:
- Psychiatric symptoms
- Personality changes
It can also cause:
- Sunflower cataracts
- Renal stones
- Osteomalacia with spontaneous fractures
Can be tricky given multisystem disorder and limited sensitivity/specificity of tests. Heterozygotes may also have borderline results. If typical presentation then diagnosis can be made on basis of:
- Kayser-Fleischer rings
- Low serum ceruloplasmin levels (<0.2g/L)
- Genetic screening of limited utility due to number of known mutations
May require extensive tests of copper metabolism especially with severe hepatic presentation, where up to 50% can have normal ceruloplasmin (an acute phase reactant) eg
- Non-caeruloplasmin-bound serum copper
- 24-h urinary copper excretion – can be abnormal in other chronic liver diseases, however. Excretion of >25micromol/24hr after penicillamine is a diagnostic test in children.
- Liver copper content (>250mcg/g dry weight) – best test when others ambiguous.
In fulminant hepatic failure the following features may suggest diagnosis:
- Haemolysis (Coombs negative)
- Alkaline phosphatase surprisingly low viz ALP:Bilirubin ratio of less than 1 has 86% sensitivity and 50% specificity in children
- Diet – chocolate, liver, nuts, mushrooms, and shellfish are high in copper
- Zinc – reduces copper absorption from gut. Monotherapy is an option for maintenance therapy.
- D-penicillamine – but note side effects, and some patients with neurological disease deteriorate on starting treatment
- Trientine – perhaps less side effects
- Liver transplantation – curative, except for long-standing neurological disease. Indicated for fulminant hepatic failure.
- Neurological function
- Liver function tests
- 24hr urinary copper excretion (aim for less than 2 micromol/d)
- Non-ceruloplasmin bound copper of 50-150mcg/L