TBX15 is not a unique adipocyte marker gene in the CRYO cohort, likely due to BMI effects as participants in CRYO-Twin have a significantly lower BMI than the participants of the bariatric surgery obesity cohorts, KOBS and RYSA (mean BMI ± SD is 37.9 ± 1.65 in KOBS; 43.1 ± 5.41 in RYSA; and 31.45 ± 5.42 in CRYO, pKOBS-CRYO = 7.75 × 10−5, pRYSA-CRYO = 1.30 × 10−8), suggesting that the adipocyte expression of TBX15 is upregulated by obesity. Here, TBX15 is linked to obesity due to melanocortin 4 receptor deficiency.