Iron Status in Black Persons Is Not Influenced by Haptoglobin Polymorphism

Abstract

Iron status in man is influenced by environmental and genetic factors. The molecular variation of haptoglobin is one of the genetic factors influencing iron status in Caucasians. Differences in iron metabolism between blacks and whites have been reported. We wanted to investigate the effect of haptoglobin polymorphism on iron status in blacks. We studied 300 African subjects who were apparently healthy with normal erythrocyte sedimentation rate and with no increase in dietary iron because of traditional beer consumption. We determined haptoglobin (Hp) phenotypes using starch gel electrophoresis and measured indirect iron status indices using standard methods. We compared iron status indices according to haptoglobin type. Ninety two individuals (31%) had Hp 1-1, 114 persons (38%) had Hp 2-1, 20 subjects (7%) had Hp 2-1(Modified) and 54 individuals (18%) had Hp 2-2 type. Haptoglobin was not detectable in 19 subjects and Hp 2-1(Johnson) was found in one subject. In both males and females, serum iron concentration, total iron binding capacity, transferrin saturation and ferritin concentration were not different with regard to Hp phenotype. These results suggest that haptoglobin phenotypic variation may not be a factor which influences iron status in black persons.

Response to Langlois et al (LE 01059)

“…Our findings, those of Beutler et al (2002) and Kasvosve et al (2002), along with the findings reported here by Langlois et al (2000), that differences are not seen in women or men over 50 years, suggest that any influence of Hp type on iron status is marginal and does not contribute to increasing morbidity in older subjects.…”

Seasonal Childhood Anaemia in West Africa Is Associated with the Haptoglobin 2-2 Genotype

“…However, we did not find an association between haptoglobin genotype and markers of iron status; it is possible, though, that monocyte iron levels may have differed between the genotypes. The association between iron homeostasis and haptoglobin genotype is controversial; some studies have found that the Hp 2/2 genotype is associated with iron loading [ 10, 32], and others have not found an association [ 33– 35]. Further studies are in progress to assess the associations between haptoglobin genotype, monocyte-iron levels, and malaria infection.…”

Host-Pathogen Interactions: The Role of Iron1,

“…Dietary iron overload is common in certain African populations and in Zimbabwean adults was associated with a 3.5-fold ([CI] 1.4-8.9) increased risk of tuberculosis (20). The haptoglobin 2-2 polymorphism is associated with increased macrophagal iron and was also associated with increased risk of death in adult Zimbabwean tuberculosis patients (21). In vitro work points to the importance of iron in the host-mycobacterium tuberculosis interaction; however, there is a paucity of in vivo data on how disturbances of host iron status affect susceptibility and disease severity.…”