Some people have genetic mutations that protect them from lipoatrophy, the loss of fat beneath the skin in the face and limbs caused by some HIV drugs, while others have genes that make them more vulnerable, say the authors of a new study published in the Journal of Infectious Diseases and reported by AIDSmap.

Lipoatrophy is believed to be caused primarily by certain antiretroviral drugs, such as Zerit (stavudine), Videx (didanosine) and zidovudine (found in Retrovir, Combivir and Trizivir), which can damage mitochondria, the energy generators inside cells—including fat cells. Previous research discovered that certain polymorphisms, or mutations, to the hemochromatosis gene (HFE)—a protein that plays a role in iron uptake—in people living with HIV protected them from mitochondrial damage leading to peripheral neuropathy, a type of nerve damage that can cause alternating numbness and pain, usually in the feet and hands.

Todd Hulgan, MD, from the Vanderbilt University School of Medicine in Nashville, and his colleagues conducted a genetic analysis of group of people selected from the AIDS Clinical Trials Group 384 study. The 96 participants they studied were part of a substudy that evaluated fat loss from antiretroviral therapy by using dual-energy X-ray absorptiometry (DEXA) scans. The majority of the participants, 90 percent, were male and 58 percent were white. On average, the group had lost 8.8 percent of their limb fat after a year on HIV treatment.

Hulgan’s team found that the participants who had a specific HFE polymorphism, 187C/G, actually gained 6.1 percent of limb fat, while another group with the 187C/C polymorphism lost 12.5 percent of limb fat. The large difference in limb fat gains and losses between the people with the two polymorphisms was statistically significant, meaning it was too great to have occurred by chance.

While Hulgan’s team acknowledges that additional research is needed to confirm the results of this study, they propose that it may one day be possible to test people for these or other polymorphisms as a way to tailor HIV treatments to individuals.