Biotinidase Deficiency

From Iusmgenetics

Contents 1 Biotinidase Deficiency 1.1 General background information 1.2 Mode of inheritance 1.3 Single important gene 1.4 Etiology 1.5 Pathogenesis 1.6 Phenotypic information 1.7 Diagnosis 1.8 Treatment 1.9 Recent research 1.10 5 important facts 1.11 Not to be confused with 1.12 Questions and answers

[edit] Biotinidase Deficiency

[edit] General background information

• 1 / 61K
• Most common in French Canadians
• An inability to release biotin form proteins and recycle it or a problem in biotin-carrier protein

[edit] Mode of inheritance

• Autosomal recessive

[edit] Single important gene

• Not really a gene, but biotin (a cofactor) is the focus here.
• Biotin may have an important regulatory role in chromatin / DNA function--particularly with histone biotinylation.
• Biotin is a cofactor for 4 carboxylases:
  • Propionyl-CoA carboxylase (amino acids)
  • Pyruvate carboxylase (gluconeogenesis)
  • Beta-methylcrotonyl-CoA carboxylase (leucine)
  • Acetyl-CoA carboxylase (biosynthesis of long-chain fatty acids)

[edit] Etiology

[edit] Pathogenesis

• Many are symptomatic early in life (young children).
• Some may not manifest until late childhood or adolescence.

[edit] Phenotypic information

• Dermatologic: alopecia, perioral rash, conjunctivitis
• Neurologic: psychomotor retardation, ataxia, seizures, deafness, blindness
• Metabolic: hypoglycemia, hyperammonemia, acidosis

• Partial deficiencies may be limited to dermatologic findings.

[edit] Diagnosis

[edit] Treatment

• Treatment of biotinidase deficiency is primarily by biotin supplementation.
  • 5-20mg / day
• There are some aspects that cannot be reversed by supplementation: hearing loss, visual abnormalities, developmental delay.

[edit] Recent research

[edit] 5 important facts

[edit] Not to be confused with

[edit] Questions and answers