The estimated prevalence is approximately 1/130 000 births.
The clinical picture is extremely heterogeneous, the age of onset varying between the perinatal period and the age of 50 years or more. Cases of hydrops foetalis have been described (rare). In 40% of cases, the neonatal period is marked by hepatosplenomegaly associated with prolonged cholestatic jaundice that usually regresses spontaneously but sometimes progresses to rapidly fatal liver failure.