The pathogenesis of HA in the course of obesity is multifaceted and includes, among others, excessive activity of the sympathetic nervous system, hyperleptinemia, increased sodium reabsorption in the renal tubules, increased intraabdominal pressure, stimulation of the RAA system, insulin resistance, or a generalized inflammatory process in the body. The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.