Biotinidase deficiency

Dr Dan J Bell and Dr Matt A. Morgan et al.

Biotinidase deficiency is a rare autosomal recessive condition in which the body is unable to break down the conjugated form of the vitamin B7 (biotin), resulting in low levels of available biotin.

Profound deficiency (<10% of normal level) is estimated at ~1:100,000 of newborns. Profound or partial deficiency (<30% of normal level) is estimated at ~1:60,000 newborns.

Symptoms usually present in infancy:

  • alopecia
  • seborrhoeic dermatitis
  • conjunctivitis and mucositis
  • erythematous rash
  • hypotonia
  • seizures
  • hearing loss
  • ataxia
  • lactic acidaemia

Variable neurologic manifestations:

  • diffuse cerebral and cerebellar atrophy on CT or MRI
  • brainstem and spinal cord myelopathy

Improves with supplemental biotin, which helps with diagnosis.

Biotinidase deficiency meets the major criteria for newborn screening in multiple countries.

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Article information

rID: 33766
Synonyms or Alternate Spellings:
  • Hypovitaminosis B7

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