Congenital bile acid synthesis defect type 4 (CBAS4) is a rare inherited disorder that affects the body's ability to produce bile acids, which are essential for digestion and absorption of fats and fat-soluble vitamins. People with CBAS4 have a deficiency in the enzyme 7α-hydroxysteroid dehydrogenase, which is responsible for the conversion of cholesterol to bile acids. This deficiency leads to an accumulation of cholesterol in the liver, which can cause liver damage and other complications. Treatment for CBAS4 typically involves dietary changes and supplementation with bile acid precursors.

The symptoms of Congenital Bile Acid Synthesis Defect Type 4 (CBAS4) vary from person to person, but may include:

-Jaundice
-Poor growth
-Failure to thrive
-Liver dysfunction
-Chronic diarrhea
-Vomiting
-Malabsorption
-Dehydration
-Weight loss
-Ascites (fluid buildup in the abdomen)
-Gallstones
-Itching
-Dark urine
-Pale stools
-Enlarged liver and/or spleen
-High levels of bile acids in the blood

Congenital bile acid synthesis defect type 4 is caused by mutations in the gene ABCB11, which encodes the bile salt export pump (BSEP). Mutations in this gene lead to a decrease in the activity of BSEP, resulting in an accumulation of bile acids in the liver and other tissues. This accumulation of bile acids can lead to a variety of symptoms, including liver damage, jaundice, and poor growth.

1. Dietary therapy: A low-fat diet is recommended to reduce the amount of bile acids produced by the body.

2. Cholestyramine: This medication binds to bile acids in the intestine, preventing them from being reabsorbed into the body.

3. Ursodeoxycholic acid (UDCA): This medication helps to reduce the amount of bile acids produced by the liver.

4. Liver transplant: In some cases, a liver transplant may be necessary to treat the condition.

5. Vitamin supplementation: Vitamin supplementation may be necessary to prevent deficiencies caused by the condition.

1. Genetic mutation: Congenital bile acid synthesis defect type 4 is caused by a genetic mutation in the gene responsible for the production of bile acids.

2. Family history: Individuals with a family history of the disorder are at an increased risk of developing the condition.

3. Ethnicity: Individuals of certain ethnic backgrounds, such as those of Middle Eastern or Mediterranean descent, are more likely to be affected by the disorder.

4. Gender: Congenital bile acid synthesis defect type 4 is more common in males than in females.

There is no cure for Congenital Bile Acid Synthesis Defect Type 4, but there are medications that can help manage the symptoms. These medications include Ursodeoxycholic acid (UDCA), which helps to reduce the amount of bile acids in the body, and fat-soluble vitamins, which help to replace the bile acids that are not being produced. Additionally, dietary changes may be recommended to reduce the amount of fat in the diet and to increase the amount of fiber.