Biotinidase Deficiency

Biotinidase deficiency is an inherited disorder in which the body is not able to process the vitamin biotin properly. Biotin is an important water-soluble vitamin that aids in the metabolism of fats, carbohydrates and proteins. 1 in every 110, 000 babies will have the deficiency.

Newborns suffering from biotinidase deficiency will appear normal at birth. The deficiency develops over time ranging from a few weeks to several years of age.

Biotinidase deficiency is an autosomal recessive disorder affecting both males and females. In individuals with this disorder, both copies of the biotinidase gene are defective. Both parents of an affected child have one abnormal copy of the gene, but usually do not show symptoms because they also have one normal copy. The normal copy provides approximately 50% of the usual enzyme activity, a level adequate for the body's needs. Individuals with one abnormal copy of the gene and 50% enzyme activity are said to be carriers or heterozygotes. As is typical of autosomal recessive inheritance, their risk for having another child with the disorder is 25% in each subsequent pregnancy.

Biotin deficiency can result in behavioural disorders, lack of coordination, learning disabilities, hearing loss, developmental delay and seizure.

Without biotinidase activity, biotin cannot be separated from foods and hence cannot be used by the body. Biotinidase enzyme also recycles biotin from enzymes that are important in metabolism.

HOWEVER, there is no need for much worry as it can be treated with oral biotin supplementation, preventing development of critical symptoms.

Here is the chemical structure of biotin: