Bile Acid Synthesis Disorders (BASD)

Bile acid synthesis disorders (BASD) are a group of rare, inherited metabolic disorders caused by defects in the enzymes that are involved in making bile acids. Bile acids promote the flow and excretion of bile, excess cholesterol and waste, and help the intestines absorb fat and fat-soluble vitamins.

When the body is unable to produce normal bile acids, it can result in interrupted bile flow (cholestasis), often resulting in malabsorption of vital nutrients and the buildup of toxic materials in the body. BASDs are typically detected during infancy.

People with cholestasis may have yellowing of the skin and eyes, failure to thrive and growth deficiency. Cholestasis may be accompanied by diarrhea, and pale, clay-colored stools caused by lack of bile. Other signs may include weakened bones caused by vitamin D deficiency, easy bleeding and bruising due to blood clotting issues from vitamin K deficiency, and vision problems due to vitamin A deficiency.

If left untreated, buildup of toxic materials may result in progressive liver disease.

Resources: National Organization for Rare Disorders; “Mechanisms of Disease: inborn errors of bile acid synthesis,” Nature Clinical Practice Gastroenterology & Hepatology.