Clinical expression of haemochromatosis in Irish C282Y homozygotes identified through family screening.
BACKGROUND
In Ireland, the homozygote frequency of the C282Y mutation in the HFE gene is 1/83. The biochemical expression of this mutation is high in haemochromatosis (HH) individuals identified through family screening, but the clinical expression of the mutation in Irish HH subjects to date has not been investigated fully.


OBJECTIVE
To determine the clinical, biochemical and histological penetrance of the C282Y mutation in Irish C282Y homozygotes identified through family screening.


METHODS
Two hundred and nine C282Y homozygous individuals comprising of 172 first-degree relatives, 31 second-degree relatives and four unrelated individuals were identified following HFE mutation analysis of 167 families. The following variables were analysed: age at identification, gender, fasting transferrin saturation, fasting serum ferritin, liver enzymes, clinical symptomatology, liver histopathology and histochemical iron staining.


RESULTS
An elevated transferrin saturation in combination with an elevated ferritin was present in 43.4% of males and 23.3% of females. Abnormal liver enzymes were found in 32.3% of males. Diabetes, a haemochromatosis-specific association, was noted in 2.8% of males. Of those individuals requiring liver histopathology evaluation, 38% had moderate-to-severe iron staining, and 42% had fibrosis; 2.8% of the biopsied cohort had cirrhosis. Thus, HH cirrhotics were identified in less than 1% of the screened population.


CONCLUSIONS
Although the homozygote frequency in Ireland is very high, the prevalence of advanced liver disease was less than 1% of the family members screened. Nevertheless, 42% of biopsied patients had histological evidence of iron overload-related architectural change and 2.8% had cirrhosis. This cohort of young people had previously unrecognized biochemical iron overload and histopathological change. This emphasizes the importance and value of both genetic and biochemical screening in first-degree relatives of identified homozygotes.
Gleeson
F
F
Centre for Liver Disease, Mater Misericordiae University Hospital, Dublin, Ireland.
Ryan
E
E
Barrett
S
S
Crowe
J
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005293:Ferritins / Q000097:blood; D005820:Genetic Testing; D006432:Hemochromatosis / Q000150:complications / Q000235:genetics* / Q000378:metabolism; D000071020:Hemochromatosis Protein; D015395:Histocompatibility Antigens Class I / Q000235:genetics; D006720:Homozygote; D006801:Humans; D007494:Ireland; D019190:Iron Overload / Q000209:etiology; D008099:Liver / Q000201:enzymology / Q000473:pathology; D008103:Liver Cirrhosis / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D008875:Middle Aged; D009154:Mutation; D019683:Penetrance; D018962:Phlebotomy; D014168:Transferrin / Q000378:metabolism
C103673:HFE protein, human; D000071020:Hemochromatosis Protein; D015395:Histocompatibility Antigens Class I; D008565:Membrane Proteins; D014168:Transferrin; D005293:Ferritins