Thrailkill et al. (2010) propose that sex-specific differences could support a contribution to susceptibility for development of renal complications in T1DM. This is interesting since the pattern of urinary MMP-9 in relation to sex reported by Thrailkill et al. (2010) in T1DM subjects, appears to coincide with that of Altemtam, Nahas & Johnson (2012) in DKD subjects with macroalbuminuria at stages 3–4, and with the findings of the present study in subjects with T2DM, with and without renal impairment. This evidence concerns the gene MMP9 and type 1 diabetes mellitus.