Beginning August 1, 2023, the University of Utah Department of Pathology and ARUP Laboratories will no longer host this mutation database. Our clinical variant data will be consolidated and shared with free publicly accessible databases such as ClinVar. For any questions or concerns related to the removal of this database from our website, please click here and one of our molecular genetics medical directors will review your submission and get back to you.

Biotinidase Deficiency and BTD  Genetics Home Reference

Initial release: January 2011
Last update: July 2020

Biotinidase deficiency (OMIM #609019) is an autosomal recessive disorder in which the body is unable to reuse or recycle biotin. The gene that encodes biotinidase is found on chromosome 3p25 and consists of four exons. The GenBank reference sequence NC_000003.10 was used.

Complete biotinidase deficiency is defined as presence of less than 10% of normal enzyme activity, while partial biotinidase deficiency is defined as having 10-30% of normal enzyme activity. Left untreated, complete biotinidase deficiency causes seizures, hypotonia, developmental delay, respiratory problems, rashes, alopecia, hearing loss, or ataxia and can culminate in coma or death. Untreated partial biotinidase deficiency may cause any of these symptoms, but they may be mild or only exhibited when the individual is stressed or suffering from illness.

ARUP Laboratories offers the following testing:
  • Full gene sequencing (test 0051730)

Database Information

The BTD database currently has 221 total entries.


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