Blue diaper syndrome
Blue diaper syndrome is a rare, inherited metabolic disorder characterized in infants by bluish urine-stained diapers. It is caused by a defect in tryptophan absorption. Bacterial degradation of the tryptophan in the intestine leads to excessive indole production and thus to indicanuria which, on oxidation to indigo blue, causes a peculiar bluish discoloration of the diaper. Symptoms typically include digestive disturbances, fever and visual problems.
Blue diaper syndrome is thought to be inherited as an autosomal recessive disease. Recent research indicates that mutations in the LAT2 and TAT1 genes might be involved in causing this syndrome.