Is there a Relationship between Genetically Determined Haptoglobin Phenotype and Insulin-Dependent Diabetes Mellitus (IDDM)?¹)

Abstract

The possible relationship between genetically determined haptoglobin phenotype and insulin-dependent diabetes (IDDM), circulating insulin antibodies and the occurrence of microangiopathy was studied in 144 IDDM. There were no differences regarding the distribution of Hp-phenotypes in 144 patients in comparison with a control population (n = 1726). Irrespective of the Hp-phenotype, the degree and severity of diabetic complications (retinopathy and/or nephropathy) significantly increased with the duration of diabetes. There was no relationship between Hp-phenotype and diabetic microangiopathy (retinopathy, nephropathy). No association existed between Hp-phenotype and the percentage of insulin antibody binding. Regardless of the Hp-phenotype, the insulin antibody concentration decreased with increasing duration of diabetes. Insulin binding parameters (maximum binding capacity and equilibrium dissociation constant) were found to vary considerably with the Hp-phenotypes among IDDM. For a given duration of diabetes the equilibrium dissociation constant increased significantly in the range from Hp 1-1, Hp 2-1 to Hp 2-2 phenotype. There was a direct relationship between the logarithm of the equilibrium dissociation constant and the degree of metabolic control, i.e. the lower the dissociation constant the better the metabolic balance. In conclusion, the results do not provide support for a putative relationship between Hp-phenotype and IDDM. However, differences between insulin binding parameters, in dependence on the Hp-phenotype may be of clinical importance.

Haptoglobin2-2 phenotype is an additional risk factor of retinopathy in type 2 diabetes mellitus

“…[2028] However two other studies by Ratzman et al (1984) and Koda et al (2002), which compared diabetic patients with and without DR and found no difference in Hp phenotype distribution in two groups. [3233] The reasons for these discrepancies may be due to differences in type of diabetes, ethnic groups and other genetic contributors and also the collected data is relatively small.…”