It is imperative to highlight that in addition to controlling the LDL receptor expression and serum LDL levels, PCSK9 appears to play conflicting roles in atherosclerosis development, inflammation, thrombosis, apoptosis, diabetes, obesity, hypertension, and Alzheimer’s disease (reviewed in [50]). The gene discussed is PCSK9; the disease is obesity due to melanocortin 4 receptor deficiency.