ADRB3 and diabetes mellitus: In 2006, one study on a single Mexican-American family [21] found a novel diabetes risk mutation in ADRB3 using linkage analysis; more recently, a GWAS study conducted on Mexican-Americans in Starr County, Texas[9] found three novel risk genes, TOMM7, HNT and PARD3B. However, it is largely unknown how much population heterogeneity in diabetes prevalence can be explained by these loci.