Hemochromatosis
Hemochromatosis is a common inherited
disorder of iron metabolism seen in, but not limited to, people
of European descent. The recessively inherited disorder has a
carrier frequency of 1/8 individuals and affects 1/250. Premature
death may be caused by complications of chronic liver disease,
hepatocellular carcinoma, or heart failure if the disease goes
untreated. Early detection and treatment with routine phlebotomy
can prevent these severe complications. For this reason, testing
for hemochromatosis is recommended in individuals with abnormal
iron studies. Elevations in serum iron levels, transferrin saturation,
and ferritin are often noted in patients with hemochromatosis.
The molecular diagnosis of hemochromatosis
involves an assay to detect two mutations within the Hfe (HLA-H)
gene. Both the C282Y and H63D mutations have been associated
with the clinical diagnosis of hemochromatosis, but the C282Y
genotype appears to be more penetrant. The polymerase chain reaction
followed by restriction endonuclease digestion is utilized to
detect these DNA alterations.
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 substituted.
Buccal swabs for DNA isolation may be accepted in some cases.
Please contact the laboratory for more information regarding
this service.
Transport:
Please contact the Molecular Diagnostic
Laboratory coordinator (1-800-473-9411) for shipping information. The specimen
should be kept at room temperature and delivered via overnight
shipping. FedEx delivery 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 a Friday can be safely designated for Monday delivery.
Analysis standards: Analysis will be completed within
1 week from
sample receipt. The quality and interpretation of test results
are assessed by the laboratory director. Technical staff 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.
Test results and their 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, 83894, 83898, 83912
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