Biotinidase - Clinical Significance

Clinical Significance

Biotin, sometimes called vitamin H, is an important water-soluble vitamin that aids in the metabolism of fats, carbohydrates and proteins. The human body cannot produce biotin, but it can obtain it from the diet, internal recycling and at some extent from intestinal bacteria. Biotin deficiency can result in behavioral disorders, lack of coordination, learning disabilities and seizure.

Unlike most vitamins, which are noncovalently bound to enzymes, biotin is chemically linked (covalently bound), and therefore cannot be easily removed from the enzyme denaturation. Without biotinidase activity, the vitamin biotin cannot be separated from foods and therefore cannot be used by the body. Biotinidase deficiency is an inherited disorder caused by mutations in the BTD gene. When biotinidase activity is deficient, biotin can be neither recycled within the body nor removed from ingested food. Nor can biotin be recycled from enzymes to which it is bound. Deficient biotinidase activity causes specific metabolic enzymes, called carboxylases, to be nonfunctional, inhibiting the proper processing of proteins, fats, and carbohydrates. Individuals lacking biotinidase activity can still have normal carboxylases if they ingest small amounts of biotin. Approximately 1 in 60,000 newborns are affected by profound (less than 10 percent of normal enzyme activity) or partial (10-30 percent of normal enzyme activity) biotinidase deficiency.