Biotinidase Deficiency

Biotinidase deficiency is caused by the lack of an enzyme called biotinidase. Without treatment, this disorder can lead to:

  • Seizures.

  • Developmental delay.

  • Eczema.

  • Hearing loss.


This is an inherited condition. It means parents pass this condition down to their children. It is caused when a man and woman who carry this gene mutation have children. In a pregnancy between 2 people who carry this gene mutation, there is a 25% chance (1 in 4) that the child will be born with the disease. There is a 50% chance (1 in 2) the child will carry this gene mutation.


Infants with biotinidase deficiency appear normal at birth. But they develop symptoms after the first weeks or months of life. Symptoms include:

  • Looseness of the muscles (hypotonia).

  • Convulsions (seizures).

  • Loss of hair (alopecia).

  • Hearing loss.

  • Metabolic acidosis, which can result in coma and death.

  • Lack of coordination of movements (ataxia).

  • Developmental delays.

  • Cradle cap (seborrheic dermatitis).

  • Loss of vision (optic nerve atrophy).


Biotinidase deficiency is treated with biotin. In infants diagnosed through screening, treatment will clear the skin rash and alopecia. It will also improve the status of the nervous system. It is necessary that treatment be managed by your caregiver. Your caregiver will make sure the biotin is in a safe and usable form and will also monitor the deficiency.