This study also examines the change of LDL and apolipoprotein B levels during a multidisciplinary obesity treatment programme.<h4>Methods</h4>This retrospective observational study included 308 adult patients with obesity who participated in a single-centre, multidisciplinary treatment programme using meal replacement (Optifast-professional). The gene discussed is APOB; the disease is obesity due to melanocortin 4 receptor deficiency.