FOXP3 and Splenomegaly: We therefore developed a clinical scoring system for Foxp3 deficiency, using a 0–3 scoring system covering splenomegaly (Fig. 2A), weight-change (Fig. 1B), behavior changes (in particular, hunching), and separate measures of dermal thickening and redness on the skin, tail, ears and around the eyes (Supplementary Table 1).