Hereditary Hemochromatosis (HH), characterized by increased iron absorption
and deposition, is one of the most common genetic diseases in people
of European ancestry.
Two mutations on the HFE gene were discovered to be primarily responsible
for HH. The first mutation results in a change of a cysteine at position
282 to a tyrosine (C282Y); the second results in a change of a histidine
at position 63 to an aspartate (H63D).
Homozygosity for the C282Y mutation has been found to be the most
common cause of HH, with a clinical penetrance of about 80%. The H63D
mutation is more prevalent than the C282Y mutation. However, the clinical
penetrance of either H63D homozygosity or C282Y/H63D compound heterozygosity
is relatively low.
The HDA-Inside HFE Genotyping is performed using Helicase-Dependent
Amplification (HDA) in a real-time PCR instrument in the presence
of a fluorescently labeled probe. Melt curve analysis is performed
after the amplification reaction to determine the genotype (Figure
Figure 1. Melt-curve analysis of the HFE genotyping kit.
Mutant alleles (green) can be easily distinguished from
the wild-types (red), while heterozygosities (blue) have
two corresponding peaks.