Biotinidase Deficiency
Biotinidase deficiency is
an inborn error of metabolism caused by the deficiency of the enzyme
biotinidase. Infants with biotinidase deficiency appear normal at birth.
However, if untreated, affected infants can develop symptoms including
hypotonia, ataxia, seizures, developmental delay, vision and hearing loss and
cutaneous problems (eg. alopecia, dermatitis, eczema). Those diagnosed at birth
should remain asymptomatic if treatment is initiated early and maintained.
Biotinidase deficiency is
typically detected very early because of newborn screening programs, which
measure biotinidase activity in dried blood spots. The Metabolic Laboratory of
the Greenwood Genetic Center is offering measurement of biotinidase activity in
plasma or serum to confirm a new diagnosis and to determine whether the patient
has partial or complete biotinidase deficiency.
Specimen requirements:
Biotinidase activity can be assessed in either serum or plasma samples.
Transport:
Collect serum in a red top tube and spin down and send frozen. Collect plasma in
a sodium heparin green top tube (5-10 mL) and send via courier or 24-hour
delivery at room temperature or spin down and send frozen (preferred).
Standard of analysis:
Biotinidase enzyme activity is determined using a p-amidobenzoic acid (PABA)
colorimetric reaction that is measured by spectrophotometry at a wavelength of
546nm.
Time required:
Analysis should be complete within one week of sample receipt.
Reporting of results:
Written reports with interpretation of results will be mailed and/or faxed to
the referring physician. When an abnormality is detected, the results will be
communicated verbally to the referring physician by telephone.
CPT Code: 82261
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