A globally occurring indel polymorphism in the promoter of the IFNA2 gene is not associated with severity of malaria but with the positivity rate of HCV
1 Department of Parasitology, Institute for Tropical Medicine, Wilhelmstr. 27, 72074 Tübingen, Germany
2 Hospital de Clinicas, Federal University of Paraná, Curitiba-PR, Brazil
3 Tran Hung Dao Hospital, No. 1, Tran Hung Dao Street, Hanoi, Vietnam
4 Department of Medical Genetics, Division of General Human Genetics, Institute of Human Genetics, Wilhelmstr. 27, 72074 Tübingen, Germany
5 Medical Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon
BMC Genetics 2008, 9:80 doi:10.1186/1471-2156-9-80Published: 3 December 2008
Type I Interferons (IFNs) are well known cytokines which exert antiviral activity, antitumor activity and immunomodulatory effects. Single-nucleotide polymorphisms (SNP) and deletions in the gene coding for IFNA2 have been shown to influence the level of expression in vitro. The indel polymorphism -305_-300delAACTTT showed the strongest effect in vitro. To analyse the worldwide distribution of this polymorphism we analyzed five different populations (586 Vietnamese, 199 Central Africans, 265 Brazilians, 108 Kaingang and 98 Guarani). To investigate a possible association with susceptibility to infectious diseases we determined the polymorphism in malaria patients suffering either mild or severe malaria and in a cohort of hepatitis C virus infected individuals.
We could detect the indel polymorphism in all populations analysed. There was no association with this polymorphism and the outcome of malaria but we found an increase of this indel polymorphism in hepatitis C virus positive individuals compared to healthy controls (p = 0.014).
Polymorphisms in genes involved in the interferon pathway have been implicated in the resistance or susceptibility against cerebral malaria and HBV. Here we show that an indel polymorphism, which mediates a disadvantageous effect in HBV patients, may also play a disadvantageous role in HCV infections stressing the importance of a fully functional interferon pathway.