This is an abnormality in the active transfer of bile salts into the ileum, related to mutations in the gene encoding the bile salt dependent Na + transporter. Diarrhoea is due to both lipid malabsorption (low bile pool) and colitis associated with bile salt malabsorption.

The diarrhoea begins during the neonatal period, it is abundant but improves if feeding ceases, and is accompanied by fatty stools. Weight- and growth-retardation set in quickly. The intestinal lining and pancreatic functions are normal.

Diagnosis is based on measuring low plasma and urinary concentrations of bile salts. An improvement is observed on cholestyramine, but diarrhoea still persists.

Management is based on a fat-free diet and cholestyramine, fat-soluble vitamins and essential fatty acids.

The mode of inheritance is autosomal and recessive.