We analysed FAIM expression in peripheral leukocytes as they were more readily accessible than liver biopsies and had also been widely used in studies on insulin signalling and metabolic diseases.34, 35, 36, 37 We recruited 33 obese subjects (19 females and 14 males, age 53±18 years old, body mass index (BMI) 30.9±4.4 kg/m2, fasting blood insulin 16.2±3.8 mU/l, HOMA-IR 5.1±1.9) and 14 lean controls (6 females and 8 males, age 26±4 years old, BMI 20.9±1.7 kg/m2, fasting blood insulin 9.2±1.2 mU/l, HOMA-IR 2.0±0.4) (Supplementary Figures S3a, c and d). This evidence concerns the gene INS and metabolic disease.