Biotinidase deficiency is an inherited disorder in which the body is unable to recycle the vitamin biotin. If this condition is not recognized and treated, its signs and symptoms typically appear within the first few months of life, although it can also become apparent later in childhood.

Mutations in the BTD gene cause biotinidase deficiency. The BTD gene provides instructions for making an enzyme called biotinidase. This enzyme recycles biotin, a B vitamin found in foods such as liver, egg yolks, and milk. Biotinidase removes biotin that is bound to proteins in food, leaving the vitamin in its free (unbound) state. Free biotin is needed by enzymes called biotin-dependent carboxylases to break down fats, proteins, and carbohydrates. Because several of these enzymes are impaired in biotinidase deficiency, the condition is considered a form of multiple carboxylase deficiency.

Profound or partial biotinidase deficiency occurs in approximately 1 in 60,000 newborns

This condition is inherited in an autosomal recessive pattern, which means both copies of the BTD gene in each cell have mutations. The parents of an individual with biotinidase deficiency each carry one copy of the mutated gene, but they typically do not have any health problems associated with the condition.

Published Date: December 01, 2014Published By: National Institutes of Health