Factor I (F-I) cleaves C3b, leading to the degradation products C3b and iC3b, which is then unable to bind F-B [26]; F-I was elevated in both obese and nonobese PCOS and associated with BMI in obese PCOS, suggesting contributions in its elevation from both the inherent PCOS phenotype and obesity. The gene discussed is C3; the disease is Obesity.