NBS- Biotinidase (BIOT)

Biotinidase deficiency is a rare inherited (autosomal recessive) metabolic disorder in which the enzyme biotinidase is deficient, preventing reuse of the vitamin biotin. Without treatment, affected infants may develop seizures, hypotonia, skin rash, hair loss, and developmental delay. Newborn screening detects it; lifelong high‑dose oral biotin usually prevents or reverses symptoms when started early.

Newborn screening for biotinidase deficiency is a heel‑prick dried blood‑spot test that measures biotinidase enzyme activity. It detects profound and partial deficiency early, often within days of birth. Early diagnosis allows prompt oral biotin supplementation, preventing seizures, developmental delay, skin rash, and hearing loss. Positive screens are confirmed by repeat enzyme testing and genetic analysis.

Typical recommended oral biotin dose for biotinidase deficiency is 5–20 mg daily for profound deficiency; partial deficiency often requires lower doses (about 1–10 mg daily). Treatment should begin as soon as diagnosis is made and is usually lifelong. Doses are given orally once daily, with adjustments based on clinical response and specialist follow-up; monitor symptoms and biochemical markers as advised.

Biotin is a water‑soluble B vitamin (vitamin B7) that functions as a cofactor for carboxylase enzymes in metabolism. Biotinidase is the enzyme that frees and recycles biotin from dietary protein‑bound forms and from degraded biotin‑dependent proteins. If biotinidase is deficient, free biotin is depleted, causing metabolic, neurological, and skin problems; treatment is biotin supplementation.

Biotinidase deficiency cannot be cured because it’s a lifelong genetic enzyme defect, but it is effectively treated. Daily oral pharmacologic-dose biotin (usually lifelong) prevents and often reverses metabolic and skin symptoms; however, delayed treatment can cause irreversible neurological damage. Early newborn screening, prompt supplementation, regular monitoring, and genetic counseling improve outcomes.

Biotin deficiency can cause hair thinning or loss, brittle nails, and a red, scaly rash around the mouth, eyes and nose. People may experience fatigue, depression, numbness or tingling in the limbs, and muscle pain; infants can show seizures and developmental delays. Risk increases with poor diet, raw egg white intake, certain medications, GI surgery, or rare genetic disorders. Treatment is dietary correction and biotin supplements.