CKMT1B and obesity due to melanocortin 4 receptor deficiency: The presence of infrequent non-synonymous variants in CKB and CKMT1B (rs146047573, rs758572075, rs1230355611, and rs149544188) was confirmed in independent study groups comprising 781 families with severe obesity, 320 children and adolescents with severe obesity, and 253 healthy lean controls (see Table 2).