Diabetic microvascular complications are not associated with two polymorphisms in the GLUT-1 and PC-1 genes regulating glucose metabolism in Caucasian type 1 diabetic patients

Background. An XbaI polymorphism in. the gene encoding the glucose transpor ter, GLUT-1, is associated with development of diabetic nephropathy in Chin ese type 2 diabetic patients. In addition, an amino acid variant (K121Q) in the gene encoding the glycoprotein plasma cell differentiating antigen (PC -1), a specific inhibitor of insulin receptor signalling, has been reported to predict a faster progression of nephropathy in Italian and British type I diabetic patients. Methods. The XbaI and K121Q polymorphisms were determined by PCR-RFLP in Da nish type I diabetic patients with nephropathy (122 men/77 women. age 40.9 +/- 9.6 years, diabetes duration 27+/-8 years) and type I diabetic patients with persistent normoalbuminuria (118 men/74 women, age 42.7 +/- 10.2 year s, diabetes duration 26 +/- 9 years). Proliferative retinopathy was present in 156 patients (40%), while 67 patients (17%) had no diabetic retinopathy . Results. There were no differences in the frequency of GLUT-1 XbaI genotype s between type I diabetic patients with diabetic nephropathy and type I dia betic patients with normoalbuminuria: 72 (41%)/87 (50%)/16 (9%) vs 94 (49%) /74 (39%)/24 (13%) had GLUT-1 XbaI +/+, +/- or genotype respectively (NS). The frequency of PC-l KK, KQ and QQ genotypes were 141 (71%)/52 (26%)/6 (3% ) rs 138 (73%)/45 (24%)/7 (4%) in patients respectively with and without ne phropathy (NS). Neither were associations between the investigated polymorp hisms and simplex or proliferative retinopathy revealed. Conclusions. Neither the PC-I K121Q nor the GLUT-1 XbaI polymorphism contri bute to the genetic susceptibility of diabetic microvascular complications in Danish type I diabetic patients.