Blood Catalase Deficiency and Diabetes in Hungary

Diabetes is a group of metabolic diseases characterized by hyperglycemia. Clinical expression of diabetes is dependent on both genetic and acquired factors (1). The metabolic effects of oxidants, which are believed to contribute to many diseases, may influence the development of some forms of diabetes. The oxidant hydrogen peroxide (H2O2) is a by-product of normal cellular respiration and is also formed from superoxide anion by the action of superoxide dismutase. H2O2 has been reported to damage pancreatic β-cells (2,3,4) and inhibit insulin signaling (5). The enzyme catalase (E.C. 1.11.1.6) has a predominant role in controlling the concentration of H2O2 (6,7), and consequently, catalase protects pancreatic β-cells from damage by H2O2 (3,8). Low catalase activities, which have been reported in patients with schizophrenia and atherosclerosis (9), are consistent with the hypothesis that long-term oxidative stress may contribute to the development of a variety of late-onset disorders, such as type 2 diabetes (10,11). Two categories of genetic deficiencies of erythrocyte catalase, which were reviewed in 1995 (12), are acatalasemia (<10% of normal activity) and hypocatalasemia (∼50% of normal activity). In Hungary, 1 acatalasemic and 12 hypocatalasemic families have been described (10,13,14). These families include 2 acatalasemic, 61 hypocatalasemic, and 66 normocatalasemic individuals. Diabetes was diagnosed in eight members of these families. Both acatalasemic individuals were women with type 2 diabetes; five of the hypocatalasemic women had type 2 diabetes, and the only man with diabetes among the eight was hypocatalasemic. Therefore, for this cohort with inherited catalase deficiency, the incidence …