Biotinidase deficiency

• biotinidase (BTD) is the only enzyme that can cleave biocytin, a product of the proteolytic digestion of holocarboxylases
  • profound BTD deficiency (less than 10% mean normal activity in serum) is an autosomal recessive disorder - this can result in neurological and cutaneous abnormalities
• both the cDNA and the genomic DNA of normal BTD gene have been isolated and characterized. The BTD gene is localized to chromosome 3p25. In a review of biotinidase deficiency it was reported that 61 mutations in three of the four exons of the BTD and one mutation in an intron gene that cause profound BTD deficiency have been reported (1)

Reference:

1. Hum Mutat. 2001 Nov;18(5):375-81