What Is Blue Diaper Syndrome?
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Blue Diaper Syndrome - Causes, Symptoms, Diagnosis, and Treatment

Published on Mar 02, 2023   -  4 min read


Blue diaper syndrome is a rare disorder with defective L-tryptophan transport resulting in blue urine. Read this article to know more.


Blue diaper syndrome is a rare genetic disorder first described in 1964. It has a very rare incidence (1:1117) and is an inborn error of metabolism. The affected infants have characteristic blue-colored urine resulting in bluish urine-stained diapers. In blue diaper syndrome, the inborn metabolic error causes an incomplete breakdown of the dietary nutrient tryptophan. Symptoms of this disorder include fever, digestive disturbances, inadequate weight gain, vomiting, constipation, irritability, and visual alterations.

What Are the Synonyms for Blue Diaper Syndrome?

The other names for blue diaper syndrome are the following.

  • Familial hypercalcemia and indicanuria.

  • Drummond syndrome.

  • Tryptophan malabsorption syndrome.

  • Familial hypercalcemia with nephrocalcinosis.

What Is Blue Diaper Syndrome?

Blue diaper syndrome is an uncommon inherited metabolic condition characterized by inefficient intestinal digestion of the vitamin tryptophan. Digestion issues, fever, irritability, and vision problems are typical symptoms. Kidney illness can also develop in some children with blue diaper syndrome. In addition, diapers stained with bluish urine are seen in babies with this condition.

Blue diaper syndrome results from a problem with tryptophan absorption. Unabsorbed tryptophan is broken down by bacteria in the intestine, causing excessive indole production. This results in indicanuria, the presence of indole in urine. The indole in urine is oxidized to indigo blue, giving a strange bluish coloring to the diaper (indoluria). Typical symptoms include fever, vision issues, and gastrointestinal abnormalities.

What Are the Causes of Blue Diaper Syndrome?

Blue diaper syndrome affects both men and women equally. The number of people affected with blue diaper syndrome in the general population is unknown. Blue diaper syndrome is thought to be an autosomal recessive disorder. Recent research suggests that mutations in the LAT2 and TAT1 genes may be involved in developing this syndrome. In addition, it is linked to the X-linked gene; thus, both parents may carry the gene for a person to develop it.

How Is Blue Diaper Syndrome Inherited?

Blue diaper syndrome is an X-linked or autosomal recessive disorder. Recessive genetic diseases develop when a person receives the same defective gene for the trait from both parents. A person will be a carrier for the disease if they have one normal gene and one sick gene, although they often would not exhibit any symptoms. Due to the X-linked nature of this disease, there is a 25 percent chance that a child may inherit normal genes from both parents and be genetically normal for that specific characteristic.

Female carriers typically do not exhibit signs of the condition since the defective gene's X chromosome is typically "shut off" in these cases. Men only have one X chromosome; therefore, they will get the illness if they inherit one sickness gene. Men with X-linked disorders pass the defective gene to all of their daughters, and they will be carriers. Because males pass their Y chromosome rather than their X chromosome to male progeny, they cannot pass an X-linked gene to their sons.

What Are the Symptoms Associated With Blue Diaper Syndrome?

Symptoms associated with blue diaper syndrome develop due to the intestinal breakdown of excessive amounts of tryptophan and the accumulation of indican and related compounds ( indigotin) in the urine (indicanuria). When intestinal bacteria break down tryptophan, it produces indole, an organic compound. Indole is absorbed and degraded into another organic compound known as indican. Indican converts to indigo blue dye when exposed to air, giving urine a distinctive blue color. Although the exact nature of the biochemical defect is not yet identified, it is thought to be related to a problem with tryptophan absorption and transport in the intestine.

Irritability, constipation, a lack of appetite, vomiting, and a failure to grow and gain weight at the anticipated rate are some of the symptoms of blue diaper syndrome. In addition, some kids may experience recurrent intestinal infections and fevers with blue diaper syndrome. Additional symptoms associated with blue diaper syndrome include hypercalcemia (abnormal calcium levels in the blood) and poor vision. Excessive calcium accumulation in the kidneys (nephrocalcinosis) leads to impaired kidney function and kidney failure. In addition, some infants with blue diaper syndrome may have eye abnormalities like an underdeveloped optic disc, a small cornea, and abnormal eye movements.

How Is Blue Diaper Syndrome Diagnosed?

Blue diaper syndrome is diagnosed after a thorough clinical examination, a detailed patient history, recognition of specific symptoms, and the presence of indican in freshly collected urine (indicanuria). Other diagnostic features that confirm blue diaper syndrome include:

  • Prolonged hypercalcemia.

  • Excess tryptophan in the child's feces.

  • Increased tryptophan levels in the intestinal lumen.

Symptoms of blue diaper syndrome can be similar to some other diseases. Intestinal infections with the bacteria Pseudomonas aeruginosa can cause stools to turn blue. This can cause a bluish appearance on a diaper and may be confused with blue diaper syndrome. Diarrhea, poor feeding habits, and irritability are all possible symptoms. However, it can be differentiated based on the presence of indican in freshly collected urine.

What Are the Treatment Options for Blue Diaper Syndrome?

Children with blue diaper syndrome are given a calcium-restricted diet. Calcium-restricted diet will aid in the prevention of kidney damage. In addition, the diet should be low in protein and high in vitamin D. Certain intestinal bacteria can be reduced or eliminated using antibiotics. Nicotinic acid may also be useful in the treatment of intestinal infections. Tryptophan-rich foods, such as turkey and warm milk, should be avoided. In addition, affected people and their families will benefit from genetic counseling. Other treatment options for blue diaper syndrome include supportive treatments and management of symptoms associated with the condition.


Blue diaper syndrome (BDS) is a very rare condition. The characteristic finding is a bluish discoloration of urine spots in affected infants' diapers. Diarrhea, insufficient weight gain, nephrocalcinosis, and hypercalcemia are the main clinical features of this condition. Treatment for blue diaper syndrome involves dietary restrictions and management of associated symptoms.

Last reviewed at:
02 Mar 2023  -  4 min read




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