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Disease Markers
Volume 11, Issue 5-6, Pages 267-274
http://dx.doi.org/10.1155/1993/678310

A Manganese Superoxide Dismutase (SOD2) Gene Polymorphism in Insulin-Dependent Diabetes Mellitus

Flemming Pociot, Tove Lorenzen, and JøRn Nerup

Stena Diabetes Center, DK-2820 Gentalte, Denmark

Received 22 September 1993

Copyright © 1993 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Interleukin I (lL-I) is selectively cytotoxic to the insulin producing beta cell of pancreatic islets. This effect may be due to IL-I induced generation of reactive oxygen species and nitric oxide. Since beta cells contain low amounts of the superoxide radical scavenger enzyme manganese superoxide dismutase (MnSOD), this may leave beta cells more susceptible to IL-I than other cell types. Genetic variation in the MnSOD locus could reflect differences in scavenger potential. We, therefore, studied possible restriction fragment length polymorphisms (RFLPs) of this locus in patients with insulin-dependent diabetes mellitus (100M) (n= 154) and control individuals (n=178), Taql revealed a double diallelic RFLP in patients as well as in controls. No overall difference in allelic or genotype frequencies were observed between 100M patients and control individuals (p=0.11) and no significant association of any particular RFLP pattern with 100M was found. Structurally polymorphic MnSOD protein variants with altered activities have been reported. If genetic variation results in MnSOD variants with reduced activities, the MnSOD locus may still be a candidate gene for 100M susceptibility. Whether the RFLPs reported in this study reflects differences in gene expression level, protein level and/or specific activity of the protein is yet to be studied.