The abnormalities of the membrane carrier proteins, mainly of glucose transporters were screened in NIDDM patients. Several polymorphisms that result in amino acid substitutions have been identified in GLUT2 and GLUT4 genes. However no significant associations have been found between NIDDM and these polymorphisms. Although the screening of ATP-sensitive potassium channel gene that has recently been isolated in pancreatic beta cells is now in progress, so far no abnormalities of the membrane carrier proteins have been reported to contribute in the causes of NIDDM.