Background:
Hereditary hemochromatosis (HH) is by far the most common genetic disease in America, affecting 1 in 200-300 Americans, or as many as 16,000 Oregonians and when detected early, quite amenable to treatment. As HH is an autosomal recessive disease, homozygotes with two defective HH genes (HFE) have an uncontrolled increase in the intestinal absorption of dietary iron. Tissue damage occurs as excess iron accumulates in the liver, pancreas, heart, pituitary, and other organs. The common clinical consequences of this iron burden are variable but can be numerous, including cirrhosis, diabetes, heart failure, impotence, amenorrhea, and arthritis. Less severe (albeit often disabling) symptoms include fatigue, weakness, arthralgias, and/or hyperpigmentation.
Reason for Referral:
Indicated in patients with a suspected iron overload disorder that cannot be explained by secondary factors (such as chronic transfusion or dyserythropoiesis).
Methodology:
The C282Y mutation in the HFE gene is detected using a real-time PCR assay and FRET (fluorescence resonance energy transfer) hybridization probes which exhibit melting curves allowing differentiation of wildtype and mutant alleles. C282Y heterozygotes are reflexed to H63D analysis as described above.
Specimen Requirements:
Blood: 4.0 mL in EDTA (purple-top) or ACD (yellow-top) or Citrate (blue-top) tube
DNA: 10ng at a minimum of 100ng/µL (DNA must be extracted in a CLIA-certified laboratory or a laboratory meeting equivalent requirements as determined by the CAP and/or CMS)
A REQUISITION FORM MUST ACCOMPANY ALL SAMPLES. Please include detailed clinical information.
Test Performed (Days):
Weekly
Turn Around Time:
7 – 10 Days
Shipment Sensitivity Requirements:
- Package and ship specimens to remain cold, but not frozen.
- Ship via overnight express, using the FedEx priority overnight label provided.
- Contact Client Services for shipping kits and instructions at (855) 535-1522.
References:
- Feder et al.Nature Genetics 13: 399-408, 1996.
- Beutler et al. Blood Cells Molecules & Disease 22: 187-194, 1996.
- Jazwinska et al. Nature Genetics 14: 249-251, 1996.
Additional Info:
This test is direct DNA-based detection by PCR of a common mutation in the HLA-H gene that causes hereditary hemochromatosis, a common iron overload disorder. C282Y heterozygotes are reflexed to H63D for an additional charge.