No matter the effectiveness of a drug, it may not work for all people. Similarly, no matter how deadly a disease is, it can’t kill everyone that contracts it. The reason behind these facts is the same: each human being has different genetic makeup. Therefore, we need to address health issues based on each individual.
Among high-risk populations, researchers have discovered a small percentage of people who have shown either delayed development or resistance of AIDS. In 1996, a form of gene CCR5, a co-receptor, was found in high frequency in the HIV-resistant individuals. After detecting the gene, researchers were able to show that HIV virus required the co-receptor to enter and infect a T-cell. The deletion form of CCR5 known as CCR5-del32 cannot perform its usual functions, nor can it act as the co-receptor for the HIV. Therefore, people with a single copy of the CCR5-del32 allele are likely to experience delayed AIDS development while those with both copies of the CCR5-del32 allele do not develop AIDS.
When researchers studied the CCR5-del32 frequency in the general population, they discovered that the CCR5-del32 allele is seen in West Asian, European, and North African populations. Carrying a mutant CCR5-del32 allele also help fight infectious microorganisms such as Shigella and Salmonella.