LEP and obesity due to melanocortin 4 receptor deficiency: Thus, microarray data obtained from 4-week- and 10-week-old lean and obese C57BL/6 mice and BTBR mice (mice line with ob/ob leptin-deficiency mutation) (GEO accession: 10785) demonstrated that obesity leads to a dramatic increase in Cdc42 expression in adipose tissue of C57BL/6 mice regardless of age, and a less significant upregulation of Cdc42 mRNA in BTBR mice, which was more robust in older animals.