Ferroportin (Q248H) mutations in African families with dietary iron overload.
BACKGROUND
Dietary iron overload found in sub-Saharan Africa might be caused by an interaction between dietary iron and an iron-loading gene. Caucasian people with ferroportin gene mutations have iron overload histologically similar to that found in African patients with iron overload. Ferroportin is also implicated in the hypoferremic response to inflammation. The prevalence of the ferroportin Q248H mutation, unique to African people, and its association with dietary iron overload, mean cell volume (MCV) and C-reactive protein (CRP) were examined in 19 southern African families.


METHODS
Polymerase chain reaction (PCR) and restriction enzyme digestion were used to identify the Q248H mutation. Statistical analysis was carried out to correlate the presence of the mutation with markers of iron overload and inflammation.


RESULTS
We identified three (1.4%) Q248H homozygotes and 53 (24.1%) heterozygotes in the families examined in the present study. There was no increased prevalence of the mutation in index subjects or their families. Logistic regression showed significantly higher serum ferritin concentrations with the mutation. The mean cell volume (MCV) was significantly lower, and the serum CRP significantly higher in subjects who carried the mutation.


CONCLUSIONS
The present study of 19 families with African iron overload failed to show evidence that the ferroportin (Q248H) mutation is responsible for the condition. Logistic regression, correcting for factors influencing iron status, did show increased ferritin levels in individuals with the mutation. The strong association with low MCV suggests the possibility that the ferroportin (Q248H) mutation might interfere with iron supply, whereas the elevated serum CRP might indicate that the ferroportin mutation influences the inflammatory response in African populations.
McNamara
Lynne
L
Division of Hematology/Oncology, Department of Medicine, University of the Witwatersrand, Johannesburg, South Africa.
Gordeuk
Victor R
VR
MacPhail
A Patrick
AP
D015415:Biomarkers / Q000097:blood; D044383:Black People / Q000235:genetics*; D002097:C-Reactive Protein / Q000235:genetics; D027682:Cation Transport Proteins / Q000097:blood*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D019190:Iron Overload / Q000453:epidemiology / Q000235:genetics*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016133:Polymerase Chain Reaction; D015995:Prevalence; D013019:South Africa / Q000453:epidemiology; D000098742:Ferroportin
D015415:Biomarkers; D027682:Cation Transport Proteins; D000098742:Ferroportin; D002097:C-Reactive Protein