LEP and obesity due to melanocortin 4 receptor deficiency: A metabolic phenotype characterized by variables suggesting that a systemic metabolic syndrome contributes significantly to the disease was supported by the literature Two longitudinal studies and two cross-sectional studies, all with low risk of bias (Tables 2, 3 and 4) [7, 35–37], suggest the existence of specific subgroups of patients characterized by a higher prevalence of metabolic factors (obesity, diabetes, hypertension and dyslipidemia) and a specific biomarker profile (plasma leptin [pLeptin], High-Sensitivity C-RP, erythrocyte sedimentation rate [ESR]) [7, 35–37].