For a paper in Scientific Reports, a Bar-Ilan University-led team describes an obesity-related role for TREM2, a gene that codes for an immune cell- and tumor-associated macrophage-expressed membrane protein previously implicated in Alzheimer's disease and other forms of neurodegeneration. Following on previous research pointing to metabolic changes in TREM2 knockout mouse models, the researchers analyzed data from the Genotype-Tissue Expression (GTEx) effort and the UK Biobank project, tracking down a TREM2 variant called rs2234256 with significant ties to body mass index in females, as well as a relationship between BMI and adipose tissue expression of TREM2 that was particularly pronounced in male participants. They note that females carrying a heterozygous version of the SNP had significantly higher BMIs than those with wildtype versions of the gene — an association that was even more pronounced in individuals who had two copies of the TREM2 variant. "The correlation between TREM2 expression level in adipose tissue and BMI is much stronger for males than females, while the effect of rs2234256 is evident only in females," the authors report, noting that "the two effects reflect different phenomena."