Bile acid synthesis disorders

Bile acid synthesis disorders (BASDs) are very rare hereditary diseases in which either enzymes of bile acid synthesis (primary BASDs) or transport enzymes for bile acids (secondary BASDs) are defective, accounting for about 1-2% of all unexplained liver diseases.

Due to the incorrect synthesis, accumulation of (toxic) intermediates and incorrectly formed bile acids occurs. Primary BASDs are subdivided into 9 sub-types according to the enzyme involved, other types are suspected. The subtypes differ partly in their symptoms, ranging from mild symptoms to type 3, which can lead to prenatal death due to its severity.

Most forms are inherited as an autosomal recessive condition. Symptoms usually appear at birth or as an infant. Secondary BASDs are similar in their symptomatology to the primary synthesis disorders. Main symptoms are hepatic cholestasis (in 7 subtypes) and fat malabsorption. As a result, symptoms such as jaundice, ascites, steatorrhea, hepatomegaly and malabsorption v. A. fat-soluble vitamins; some subtypes have neonatal hepatitis.

The vitamin deficiency causes symptoms such as rickets, neurological disorders, night blindness or bleeding tendency. Left untreated, BASDs can lead to liver cirrhosis and ultimately, liver failure with death. Due to the similarity of the symptoms to other liver diseases and the very low incidence, the clinical diagnosis is often difficult. If the disease is detected and treated in good time, the prognosis is good.