PTX3 and obesity due to melanocortin 4 receptor deficiency: Results demonstrate that: 1) ACS leads to plasma PTX3 elevation in both non-obese and obese patients; 2) obesity is however associated with lower PTX3 in people with and without ACS; 3) lower PTX3 is also observed in patients with normal compared to those with high waist circumference, a marker of abdominal fat accumulation.