For example, in Polish women, the levels of TNF-α varied significantly (p < 0.001) from 2.9 ± 2.2 pg/mL in the lean participants to 6.5 ± 3.1 pg/mL in overweight individuals, 6.8 ± 3.1 pg/mL in participants with obesity, and 7.4 ± 2.6 pg/mL in very obese participants [23]. The gene discussed is TNF; the disease is obesity due to melanocortin 4 receptor deficiency.