Biotinidase deficiency is an inherited ailment where the body struggles to process biotin (vitamin B7) due to an insufficient presence of the enzyme biotinidase.
Profound biotinidase deficiency is diagnosed when individuals possess less than 10% of the typical biotinidase enzyme levels, resulting in severe symptoms without intervention. Untreated cases of this deficiency can lead to seizures, muscle weakness, coordination difficulties, vision and hearing impairments, skin issues, respiratory challenges, hair loss, fungal infections, and developmental delays. These symptoms usually manifest within the first few months of life and can be life-threatening if left untreated. On the other hand, partial biotinidase deficiency, found in individuals with 10% to 30% of the enzyme’s normal levels, represents a milder form of the disorder, with symptoms potentially emerging during illness or stress or remaining less severe overall. With early detection and treatment, a person with biotinidase deficiency can live a completely normal life.
Biotinidase deficiency is caused by pathogenic (disease-causing) variants in the BTD and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background. For example, individuals of Ashkenazi Jewish descent have a 1 in 15 chance to be a carrier.
Other names for this condition are BIOT, BTD deficiency, late-onset biotin-responsive multiple carboxylase deficiency, and/or late-onset multiple carboxylase deficiency.
Resources:
National Organization for Rare Disorders
Revised September 2023
