A new study in Nature Medicine indicates that the gene that He Jiankui, PhD, modified in twin baby girls to mitigate HIV risk in China last year, causing outrage amongst the global scientific community, is associated with premature death.
The delta-32 mutation appears to provide HIV resistance when it occurs on both copies of the CCR5 gene, while one copy of the mutation provides weaker protection. Researchers looked for this mutation in a U.K. database of more than 400,000 volunteers, finding that those with two copies of the mutated gene were 20% more likely to die by age 76 than those with one or no copies. The connection between the gene mutation and shortened lifespan cannot yet be explained by scientists.
George Q. Daley, MD, PhD, dean of Harvard Medical School, told Scientific American that the new study is a reminder of scientists’ limited understanding of genetics. “It’s a lesson in humility, I think, more than anything,” he said. “What this study also is concrete evidence of is the ignorance that we have.”