What are the tests for alagille syndrome?

Liver biopsy: Liver biopsy is probably the most effective means of diagnosis. Many people with alagille syndrome do have characteristic facial features and some unusual x-ray findings but not in all cases.

Genetic test, like : Cgh for an autisomal dominant mutation in the jagged-1 gene on the short arm of chromosome 20, 20p12. Because of "variable penetrance" some parents don't have noticeable symptoms, especially if they have mosaicism, i.e., some, but not all, of their cells carry the mutation. Therefore, although 15% of cases are "sporadic, " i.e., from new mutations, it is recommended that parents be tested.