The discovery not only marks the first genetic risk factor for HIV found only in people of African descent but also debunks the myth that people in sub-Saharan Africa were more likely to get HIV because of differences in their sexual behaviour, researchers added.
Research at University College London and the University of Texas found people of African descent have a variation of the Duffy Antigen Receptor for Chemokines (DARC) gene which may interfere with their ability to fight HIV in its early stages. The gene influences the levels of chemicals called chemokines, which play a role in the body's defenses against viruses.
The variation is present in approximately 90 percent of Africans and is responsible for millions of extra HIV cases in sub-Saharan Africa, researchers found in the study titled "The Cell Host and Microbe Study."
Paradoxically, the study also found that people with the gene appeared to have a longer life span with HIV than others. People who carry the DARC gene survive on average an extra two years longer than those who do not, said the researchers.
HIV affects 25 million people in sub-Saharan Africa today and around 90 per cent of people in Africa carry the genetic variation, meaning that it may be responsible for an estimated 11 per cent of the HIV cases there.
