Genetic variation in ALDH4A1 is associated with muscle health over the lifespan and across species.

The influence of genetic variation on the aging process, including the incidence and severity of age-related diseases, is complex. Here we define the evolutionarily conserved mitochondrial enzyme ALH-6/ALDH4A1 as a predictive biomarker for age-related changes in muscle health by combining genetics and a gene-wide association scanning (GeneWAS) from older human participants of the US Health and Retirement Study (HRS). In a screen for mutations that activate oxidative stress responses, specifically in the muscle of , we identified 96 independent genetic mutants harboring loss-of-function alleles of , exclusively. Each of these genetic mutations mapped to the ALH-6 polypeptide and led to the age-dependent loss of muscle health. Intriguingly, genetic variants in show associations with age-related muscle-related function in humans. Taken together, our work uncovers mitochondrial as a critical component to impact normal muscle aging across species and a predictive biomarker for muscle health over the lifespan.