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Biotinidase Deficiency

[Absent/Reduced Biotinidase activity] 


Differential Diagnosis: Biotinidase deficiency; see C5-OH for non-biotinidase associated conditions 

Condition Description: Biotinidase deficiency results from defective activity of the biotinidase enzyme. When identified (possible) through elevated C5-OH, 3-hydroxyisovaleric acid and 3-methylcrotonylglycine are elevated and holocarboxylase synthase deficiency must be considered 

You Should Take the Following IMMEDIATE Actions:

  • Contact family to inform them of the newborn screening result and ascertain clinical status (poor feeding, lethargy, hypotonia)
  • See and evaluate infant
  • Consultation/Referral to a metabolic specialist to determine appropriate follow-up
  • If infant can not be seen immediately at metabolic specialist, undertake confirmatory testing in consultation with a metabolic specialist
  • Emergency treatment if symptomatic
  • Report findings to state newborn screening program (Carleigh Soule at 307-777-6297) 

Confirmation of Diagnosis: Enzyme assay for biotinidase reveals low activity. Plasma acylcarnitine analysis may show normal or increased 3-hydroxyisovaleric acid and 3-methylcrotonylglycine. C5-OH acylcarnitine may be high but lack of an abnormal acylcarnitine profile does not rule out biotinidase deficiency 

Clinical Expectations: The neonate is usually asymptomatic but episodic hypoglycemia, lethargy, hypotonia, and mild developmental delay can occur at any time from the neonatal period through childhood. Untreated biotinidase deficiency leads to developmental delay, seizures, alopecia, and hearing deficits. Biotin treatment is available and highly effective 

Additional Information: (Click on the name to take you to the website) 

Gene Tests/Gene Clinics                                             Wyoming Department of Health                              

Online Mendelian In Men                                             Colorado Newborn Screening                            

Genetics Home Reference


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