INS and obesity due to melanocortin 4 receptor deficiency: AT RNA sequencing was analyzed using linear mixed modeling and pathway enrichment for: (1) sex differences in individual twins, adjusted for BMI, (2) sex-stratified effects of acquired obesity (ΔBMI between co-twins separately in females and males), (3) sex-specific effects of obesity (differences in the ΔBMI effect between sexes).<h4>Results</h4>(1) AT transcriptional profiles differed between sexes, associating with insulin sensitivity.