While serum visfatin levels do not change with the acute changes in glucose metabolism, the positive correlations of fasting serum visfatin with glucose, insulin and HOMA-IR and the negative correlation between fasting serum visfatin and glucose/insulin ratio in our combined group of subjects suggest that serum visfatin level may be related with hyperglycemia and hyperinsulinism. The gene discussed is INS; the disease is hyperinsulinism.