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Prevalence
- Reported U.S. population prevalence estimates of iron overloading
(based on random non-fasting elevated transferrin saturation, TS values) range from 1% to 6%.
- A lower percentage of people who initially have a random elevated TS
also have persistently elevated TS: estimates range from 35% to 50%.
- An even lower percentage of people with persistently elevated TS
measures also have elevated serum ferritin values.
- Thus, the proportion of people who will develop clinical signs and
symptoms of hemochromatosis is even lower than the proportion of people
with elevated serum ferritin, SF values.
HFE gene mutations
- Two HFE gene mutations, C282Y and H63D, account for the majority of
hereditary hemochromatosis cases; C282Y is most common.
- Hereditary hemochromatosis is inherited in an autosomal recessive
pattern.
HFE genotype frequencies
- The population prevalence of HFE mutations depends on race and
ethnicity but is most prevalent among persons of European origin and
descent.
Penetrance
- Of people with HFE gene mutations, only a subset will develop
an elevated TS. Of those with an elevated TS, only a subset will develop
an elevated SF. Of those with an elevated SF, only a subset will develop
hemochromatosis symptoms. Of those with symptoms, only a subset will
develop clinical signs consistent with hemochromatosis.
- Most clinicians reserve the hemochromatosis diagnosis for patients
whose signs and symptoms are clearly referable to documented iron overload
as reflected by serum iron testing measurements.
- Iron status testing is more clinically relevant than genetic testing
for identifying those who have hemochromatosis.
Population screening
- At this time, CDC does not recommend population screening for HFE
gene mutations because of the uncertainty about what proportion of people
with HFE gene mutations will develop hemochromatosis.
This is an optional self-quiz and is not required for continuing
education credit.
Select the best answers below. If you need help, feel free to
go back to Prevalence and review.
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