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 with 4:
- developmental delay
- seborrhoeic dermatitis
- conjunctivitis and mucositis
- erythematous rash
- lactic acidaemia
In the long term if untreated, hearing loss and optic atrophy can also occur 4.
In biotinidase deficiency in children the neuroimaging findings are relatively non-specific 4.
- diffuse cerebral and white matter atrophy
- dilation of the ventricles and extra-axial CSF spaces
- diffuse or patchy signal abnormalities within cerebral and cerebellar white matter
- sub-cortical cyst formation
- the same changes as above
- signal abnormalities of the spinal cord may also be seen
- DWI: areas of restricted diffusion within the signal abnormalities
- sometimes elevated lactate
- reduced NAA
Treatment and prognosis
Improves with supplemental biotin, which helps with diagnosis.
Biotinidase deficiency meets the major criteria for newborn screening in multiple countries.
- 1. Raha S, Udani V. Biotinidase deficiency presenting as recurrent myelopathy in a 7-year-old boy and a review of the literature. Pediatr. Neurol. 2011;45 (4): 261-4. doi:10.1016/j.pediatrneurol.2011.06.010 - Pubmed citation
- 2. Wolf B. Biotinidase deficiency: "if you have to have an inherited metabolic disease, this is the one to have". Genet. Med. 2012;14 (6): 565-75. doi:10.1038/gim.2011.6 - Pubmed citation
- 3. Wolf B. Clinical issues and frequent questions about biotinidase deficiency. Mol. Genet. Metab. 2010;100 (1): 6-13. doi:10.1016/j.ymgme.2010.01.003 - Pubmed citation
- 4. Reddy N, Calloni SF, Vernon HJ, Boltshauser E, Huisman TAGM, Soares BP. Neuroimaging Findings of Organic Acidemias and Aminoacidopathies. (2018) Radiographics. 38 (3): 912-931. doi:10.1148/rg.2018170042 - Pubmed