OMIM ID:
Blue Diaper Syndrome
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
A single patient has been reported with microcornea, optic nerve hypoplasia, and ‘abnormal’ eye movements. The full ocular phenotype is unknown but ‘visual problems’ are sometimes mentioned in other reports.
Systemic Features
Nephrocalcinosis and blue urine are the major systemic manifestations of blue diaper syndrome. Symptoms of fever, constipation, poor weight gain, failure to thrive, and irritability can also be part of the syndrome.
Genetics
Inheritance
This is considered an autosomal recessive disorder although an X-linked defect cannot be ruled out since reported patients have been male. Parental consanguinity is present in some families. Nothing is known about the mutation or its locus. Intestinal transport of tryptophan is defective and bacterial degradation results in excessive indole production. Oxidation in the urine to indigo blue results in the characteristic discoloration.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.