Thus, iron-treated Tmprss6−/− and Tmprss6−/−mice showed smaller and multilocular lipid droplets compared to wild-type controls (Fig. 2a, c), indicating that the observed resistance to the obesity-induced phenotype in Tmprss6−/− mice was not only related to a decrease in WAT hypertrophy, but also to a reduction in the lipid content of BAT. The gene discussed is TMPRSS6; the disease is obesity due to melanocortin 4 receptor deficiency.