IGFBP3 and type 2 diabetes mellitus: We have confirmed linkage to early-onset T2D on chromosome 7p, and examined common variants across positional candidate genes GCK1, IL6, IGFBPI and IGFBP3. A variant of the GCK1 gene, rs730497, appears to play a role in susceptibility to earlier age of ESRD onset in African Americans.