Allan-Herndon-Dudley Syndrome
Allan-Herndon-Dudley syndrome is an X-linked mental
retardation condition caused by mutations in the monocarboxylate
transporter 8 (MCT8) gene. The features of this condition include
moderate-severe mental retardation, impaired speech, hypotonia, muscle
weakness, and contractures, Mutations in this gene, located at Xq13.2,
impair the transport of T3 into neurons as evidenced by elevated free T3
and decreased free T4 in the blood of affected patients.
Specimen requirements: 5 to 10 ml of peripheral
blood collected in an EDTA (lavender 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 the Molecular
Diagnostic Lab Coordinator (1-800-473-9411) 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 six weeks of sample receipt. The laboratory director and
technical staff members independently assess the quality and
interpretation of the test. The Greenwood Genetic Center Molecular
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 are available
upon request.
CPT Codes:
- Unknown mutation: 83890, 83894(x4), 83898(x6),
83904(x6), 83912
- Known mutation: 83890, 83898, 83904(x2), 83909,
83912
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