Biotinidase deficiency is a genetic rare disease that have reported in 1 of 100.000 people. With it, this disease is a treatable, metabolic disorder that occurs in the partial absence or complete absence of biotinidase enzyme. Biotin is an indispensable vitamin for metabolic processes. With it, in these patients Biotin or with other name vitamin H, cannot regularly processed also.
The infants may not show any signs because of the disease at birth. The symptoms may become apparent within the first few weeks or months after birth. 25 to 50 percent from these babies that born with biotinidase deficiency will have balance problems and ataxia, red eye and conjunctivitis, sensorineural hearing loss, lethargy, slight decreased blood ammonia concentration level, breathing problems and visual problems. In 10 to 25 percent of these patients may develop serious problems like loss of consciousness loss and coma, vomiting, diarrhea and systemic fungal infections also.
This disease has an autosomal recessive inheritance that caused by BTD gene mutation. With it, BTD gene is required for the production of the biotinidase enzyme, that have an important function for metabolism of the one essential vitamin known as biotin. This gene have observed in 3p25 region on the long arm of chromosome 3. Because of autosomal recessive inheritance, if one from family member have this disease; all the children will have the disease by %25 rate also. The risk for being a carrier like the parents for this disease is 50 percent for every birth.
After birth, it is possible to test blood serum biotinidase activity for diagnosis. If the measured activity is, %10 less than from mean normal activity, the disease is profound biotinidase deficiency. If the measured activity is %10 to %30 of mean normal serum biotinidase activity, this disease is partial biotinidase deficiency.
Identifying BTD gene on molecular genetic testing is definite diagnosis for biotinidase deficiency.
This disease can treated with oral biotin supplements. The treatment must start as soon as the disease is diagnosed. Symptoms of this disorder can decrease by biotin treatment. However, these patients needs to take biotin supplement throughout the lifetime. Avoid raw egg in this patients, because egg white will bind bind biotin and decrease its bioavailability. If prenatal diagnosis made and if the baby have biotinidase deficiency also, biotin supplementation of the mother is necessary.
If the diagnosis is made immediately after birth and the biotin supplement is started, this disease will not affect the life expectancy. Untreated patients can develop life threatening symptoms like ataxia, lethargy, consciousness loss, vomiting and coma in early period. But, rarely causes to death. For this reason diagnosing this disease is very important.