ACOX2 Deficiency (Congenital Bile Acid Synthesis Defect 6)
Autosomal recessive
Caused by loss-of-function changes in both copies of ACOX2, which encodes a peroxisomal enzyme needed to shorten bile acid precursors. Without it, C27 bile acid intermediates accumulate and can harm the liver.
Signs and symptoms
Persistently raised liver enzymes and, in some, liver fibrosis, sometimes found by chance in childhood. Some people have had mild neurological features such as unsteadiness or learning difficulties. Only a few people have been reported, so the full range of features is not yet known.
What a diagnosis changes
Diagnosis is supported by specialist bile acid analysis of urine or blood. Care involves liver monitoring by a hepatologist, and bile acid therapy has been used in some people, though experience is limited. Both parents of an affected child are usually carriers, so each further child has a 1 in 4 chance of being affected; genetic counselling and carrier testing of relatives are available.
Genes analysed
Also known as
ACOX2 congenital bile acid synthesis defect; bile acid synthesis defect, congenital, 6; congenital bile acid synthesis defect type 6; CBAS6; congenital bile acid synthesis defect caused by mutation in ACOX2
