We discovered that the expression levels of ELOVL3, ELOVL5 and ELOVL6 increased similarly to estimated elongase activity (P<0.05), while the mRNA expression level of ELOVL1 decreased during the first year after obesity surgery (P=6 × 10−5). The gene discussed is ELOVL3; the disease is obesity due to melanocortin 4 receptor deficiency.