Mouse knockouts of individual p160 coactivators have distinct phenotypes: p/CIP (also called AIB1/ACTR/RAC3/NCoA1/SRC3) knockout mice have a somatic growth defect [9], [10], TIF2 (SRC2/GRIP2/NCoA2) knockouts are resistant to high fat diet-induced obesity with elevated adaptive thermogenesis [11], and SRC-1 knockouts exhibit an obese phenotype when challenged with a high fat diet [11], [12]. The gene discussed is NCOA2; the disease is obesity due to melanocortin 4 receptor deficiency.