NEW YORK (GenomeWeb) – Variants in a gene associated with red hair and pale skin appear to influence facial aging in individuals of European ancestry, according to a study published today in Current Biology.
Researchers from the Netherlands, China, the UK, and Germany began by performing a genome-wide association with nearly 2,700 elderly Dutch individuals from an ongoing prospective cohort study called the Rotterdam study. Dozens of individuals estimated participants' ages based on their facial features, making it possible to pick out people who looked older or younger than their chronological age.
The team's search led to variants in the melanocortin 1 receptor gene MC1R that were more common in individuals with facial features perceived as older than expected based their actual age — two years, on average. That association held in two more European cohorts, a group of 599 individuals from the Leiden Longevity Study and 1,173 participants in the TwinsUK study.
"For the first time, a gene has been found that explains in part why some people look older and others younger for their age," co-senior author Manfred Kayser, a genetic identification researcher at Erasmus MC University Medical Center Rotterdam, said in a statement.
Past studies suggest perceived age has a heritable component and is linked to broader health features, he and his colleagues noted. With that in mind, they assessed array-based genotypes for 2,693 Rotterdam study participants of Dutch European descent, looking for variants that were over-represented in individuals with speedy or slow facial aging.
The analysis did not unearth SNPs with genome-wide significant ties to facial aging or wrinkling, the researchers reported, though they did see a more subtle association between facial aging and a chromosome 16 locus that spanned MC1R. By combining information across several SNPs at this site, the team came up with a compound marker that did coincide with facial aging in a genome-wide significant manner. Compared with individuals carrying wild type or heterozygous versions of these variants, the participants with two copies of age-associated alleles appeared an average of two years older than their age.
The same patterns turned up when the researchers tested 599 Leiden Longevity Study participants and 1,173 individuals of European ancestry from the TwinsUK study, where the compound marker showed significant ties to facial aging in a combined cohort analysis, even after adjusting for age, sex, and wrinkles.
Although variants in MC1R have previously been linked to skin pigmentation or coloring, the researchers found that the current association with facial aging seemed to persist even after adjusting for such skin features, suggesting the gene may have additional aging-related roles.
"This association was independent of age, sex, skin color, and sun damage (wrinkling, pigmented spots) and persisted through different sun-exposure levels," Kayser and co-authors noted. "Hence, a role for MC1R in youthful looks independent of its known melanin synthesis function is suggested."