Using an approach which conditioned on linkage in one region to identify evidence of linkage elsewhere, a linkage study of T2DM in Mexican Americans from Starr County, Texas, identified the interaction of genes on chromosomes 2 (CAPN10 (Calpain 10), then NIDDM1) and 15 (near CYP19 (Cytochrome P450, family 19, or Aromatase)) in contributiing to T2DM susceptibility [66]. This evidence concerns the gene CYP19A1 and type 2 diabetes mellitus.