Linkage of mild malaria to the major histocompatibility complex in families living in Burkina Faso.
ABSTRACT Tumor necrosis factor alpha (TNF alpha) is thought to be a critical mediator of malaria fever, and mild malaria was previously reported to be linked to the MHC region containing the tumor necrosis factor alpha gene (TNF). Thirty-four families from Burkina Faso were analyzed to test for linkage between polymorphisms within the MHC region and mild malaria using the maximum-likelihood-binomial (MLB) program. Two-point analysis indicated linkage of mild malaria to TNFd (LOD = 3.27; P = 5.44 x 10(-5)). Using multipoint analysis, we also found evidence for linkage of mild malaria to the MHC region, with a peak close to TNF (LOD = 3.86; P = 1.22 x 10(-5)). Our results support genes within the MHC region being involved in mild malaria. In particular, the genetic variation within TNF may influence susceptibility to mild malaria. Nevertheless, TNF-238, TNF-244 and TNF-308 polymorphisms are unlikely to explain linkage of mild malaria to the MHC region, and the causal mutations remain to be identified.
Article: Family-based association of a low producing lymphotoxin-alpha allele with reduced Plasmodium falciparum parasitemia.[show abstract] [hide abstract]
ABSTRACT: Tumor necrosis factor (TNF)-related genes are thought to play a role in human malaria. TNF polymorphisms have been associated with severe malaria, mild malaria, and parasitemia. Lymphotoxin-alpha gene (LTA) that belongs to the TNF family is one such candidate gene. Here we report the family-based association analysis of a cis-regulatory lymphotoxin-alpha polymorphism with parasitemia in two independent populations living in Burkina Faso. Analysis of 199 subjects (34 families) living in an urban endemic area revealed the association of the low producing LTA+80A allele with reduced parasitemia. Furthermore, there was evidence of significant LTA+80-by-age and LTA+80-by-gender interactions. In another set of 318 residents (55 families) in a rural endemic area, we found both the association of the low producing LTA+80A allele with reduced parasitemia and LTA+80-by-age and LTA+80-by-gender interactions. This study suggests that LTA+80 polymorphism influences parasitemia and acts in an age- and gender-dependent manner.Microbes and Infection 06/2008; 10(6):673-9. · 3.10 Impact Factor
Medical journal of the Islamic Republic of Iran 01/2010;
Article: Genome wide linkage study, using a 250K SNP map, of Plasmodium falciparum infection and mild malaria attack in a Senegalese population.[show abstract] [hide abstract]
ABSTRACT: Multiple factors are involved in the variability of host's response to P. falciparum infection, like the intensity and seasonality of malaria transmission, the virulence of parasite and host characteristics like age or genetic make-up. Although admitted nowadays, the involvement of host genetic factors remains unclear. Discordant results exist, even concerning the best-known malaria resistance genes that determine the structure or function of red blood cells. Here we report on a genome-wide linkage and association study for P. falciparum infection intensity and mild malaria attack among a Senegalese population of children and young adults from 2 to 18 years old. A high density single nucleotide polymorphisms (SNP) genome scan (Affimetrix GeneChip Human Mapping 250K-nsp) was performed for 626 individuals: i.e. 249 parents and 377 children out of the 504 ones included in the follow-up. The population belongs to a unique ethnic group and was closely followed-up during 3 years. Genome-wide linkage analyses were performed on four clinical and parasitological phenotypes and association analyses using the family based association tests (FBAT) method were carried out in regions previously linked to malaria phenotypes in literature and in the regions for which we identified a linkage peak. Analyses revealed three strongly suggestive evidences for linkage: between mild malaria attack and both the 6p25.1 and the 12q22 regions (empirical p-value=5x10(-5) and 9x10(-5) respectively), and between the 20p11q11 region and the prevalence of parasite density in asymptomatic children (empirical p-value=1.5x10(-4)). Family based association analysis pointed out one significant association between the intensity of plasmodial infection and a polymorphism located in ARHGAP26 gene in the 5q31-q33 region (p-value=3.7x10(-5)). This study identified three candidate regions, two of them containing genes that could point out new pathways implicated in the response to malaria infection. Furthermore, we detected one gene associated with malaria infection in the 5q31-q33 region.PLoS ONE 01/2010; 5(7):e11616. · 4.09 Impact Factor