Other risk factors for AMD, including smoking, hypertension, and obesity, have been associated with reduced serum concentrations of CFH [44-46], and subtle variations in plasma components of the alternative pathway could have a significant impact on its local activation in response to stimuli even though the researchers found no differences between the AMD and control groups regarding the CFH and C3 levels. The gene discussed is C3; the disease is obesity due to melanocortin 4 receptor deficiency.