Biotinidase Deficiency - BTD Sequencing
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.
Sequencing of the
BTD gene is available from the Metabolic Laboratory of the
Greenwood Genetic Center. Molecular testing is useful to identify the
disease causing mutations within a family to allow for carrier testing
and prenatal diagnosis. Molecular testing can also be beneficial when
enzyme analysis results are ambiguous. Enzyme analysis of biotinidase
activity is also available.
Specimen
requirements: 5 to 10
ml of peripheral blood collected in an EDTA (lavendar top) Vacutainer
tube is preferred. The minimal blood needed for reliable DNA isolation
is 3 ml. If necessary, ACD solution A Vacutainer tubes (yellow top) may
be submitted. Please contact the laboratory for more information.
Transport:
Please contact Tim Wood (1-800-473-9411), or the molecular
diagnostic lab coordinator, for shipping information. The specimen
should be kept at room temperature and delivered via overnight
shipping. FedEx is preferred. If shipment is delayed by one or two
days, the specimen should be refrigerated and shipped at room
temperature. Do not freeze the specimen. Samples collected on
Friday can be safely designated for Monday delivery.
Analysis
standards: Analysis
will be complete within 4 weeks of sample receipt. The lab director
assesses the quality and interpretation of results. Technical staff
members independently assess the quality and interpretation of the
test. The Greenwood Genetic Center Metabolic Diagnostic Laboratory is
CLIA certified and actively participates in CAP proficiency surveys.
Reporting of
Test Results: Test
results with interpretation will be mailed and/or faxed following
completion of the test. Verbal reports will be telephoned to the
person(s) requesting the test when an abnormal test result occurs.
Consultation with the laboratory director and explanations of testing
protocols will be supplied upon request.
CPT Codes:
83890, 83898 (x4), 83904 (x3), 83909 (x3), 83912
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