Biotinidase Deficiency

The kit is based on a catalysis reaction of biotinidase extracted from the sample. In the presence of an artificial substrate, biotinidase will release 4-aminobenzoic acid (PABA). The generated PABA will react with sodium nitrite to form a diazotized compound. The purple coloration obtained can be directly measured by absorption and is directly proportional to the biotinidase activity in the sample.

Biotin (also known as vitamin H or B8) is an essential vitamin belonging to the vitamin B complex. Biotin functions as a coenzyme essential for the proper functioning of gluconeogenesis, fatty acid synthesis and catabolism of various branched chain amino acids.

Biotinidase deficiency is a congenital error in biotin recycling metabolism. 

A deep biotinidase deficiency is defined as a residual activity < 10% of normal mean serum biotinidase activity, while a partial deficiency is defined as a residual activity between 10% and 30% of normal mean activity.

Young children with a profound biotinidase deficiency diagnosis usually develop symptoms of severe neurological abnormalities including convulsions, hypotonia, ataxia, psychomotor retardation, optic atrophy, sensorineural deafness and skin disorders. Later, weakness of the motor limbs and spastic paresis also develop. 

Individuals with partial biotinidase deficiency may suffer from symptoms of hypotonia, skin rashes and hair loss, particularly during periods of stress such as a prolonged infection.

The treatment consists of daily vitamin supplements of biotin taken by mouth. This treatment is remarkably effective if started at a very early age.