It is caused by a defect in tryptophan absorption. Bacterial degradation of unabsorbed 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 (indoluria). Symptoms typically include digestive disturbances, fever and visual problems. Some may also develop disease due to the incomplete breakdown of tryptophan.[3]
It was characterized in 1964, and inherited in an autosomal recessive pattern although X-linked recessive inheritance has not been completely ruled out since reported patients have been male.[4]
If this syndrome is X linked, the chance for a child to receive normal genes from both parents and be genetically normal for that particular trait is 25%. If an individual receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms.[5] Carrier females usually do not display symptoms of the disorder because it is usually the X chromosome with the abnormal gene that is "turned off".[3]
Parents can undergo genetic testing to see if their child will get this syndrome, but most do not find out until they see the symptoms mentioned below.[5]
Signs and symptoms
The signs and symptoms of blue diaper syndrome may include irritability, constipation, poor appetite, vomiting, and poor growth. Some children experience frequent fevers and intestinal infections.[1][3]
Hypercalcemia could be a potential issue in affected children. Some children with blue diaper syndrome have eye or vision issues, particularly underdeveloped portions of the eye, including the cornea and optic disc.[citation needed]
Genetics
Blue diaper syndrome affects males and females equally. The number of people affected in the general population is unknown.[1]
Although the disease is most likely recessive, it could be X-linked.[6]
Recent research indicates that mutations in the LAT2[7] and TAT1[8]genes might be involved in causing this syndrome.
It is linked to X linked gene and in order for a person to develop it, both parents must carry the gene.[3] This syndrome is diagnosed through clinical evaluation and a fresh urine sample [3]
Diagnosis
A diagnosis is usually made through clinical evaluation, observing detailed patient history then identifying the possible characteristic symptoms and testing fresh urine samples to enhance such evidence.[1]
Treatment
Children with blue diaper syndrome are put on restricted diets. This is in effort to reduce kidney damage. Restrictions include: calcium, protein, vitamin D, and tryptophan. Calcium is restricted to help prevent kidney damage.[3] Examples of food with high levels of tryptophan include turkey and milk.[3] Diets are also expected to be low in protein, which will help prevent symptoms, along with restricting vitamin D intake. Antibiotics may be used to control or eliminate particular intestinal bacteria.[citation needed]
Genetic counseling can also be beneficial, as well as taking part in clinical trials.[9]
^Park SY, Kim JK, Kim IJ, Choi BK, Jung KY, Lee S, Park KJ, Chairoungdua A, Kanai Y, Endou H, Kim do K (2005). "Reabsorption of neutral amino acids mediated by amino acid transporter LAT2 and TAT1 in the basolateral membrane of proximal tubule". Arch Pharm Res. 28 (4): 421–32. doi:10.1007/BF02977671. PMID15918515. S2CID2139640.
^Kim do K, Kanai Y, Matsuo H, Kim JY, Chairoungdua A, Kobayashi Y, Enomoto A, Cha SH, Goya T, Endou H (2002). "The human T-type amino acid transporter-1: characterization, gene organization, and chromosomal location". Genomics. 79 (1): 95–103. doi:10.1006/geno.2001.6678. PMID11827462.
