Abstract

BACKGROUND
To investigate whether a TNF-g gene polymorphism is associated with the development of insulin-dependent diabetes mellitus, we analyzed the TNF-g gene polymorphism with restriction enzyme Ncol in 38 Korean patients with insulin -dependent diabetes mellitus(IDDM) and in 150 healthy controls. METHODS: Genomic DNA was extracted from white blood cells, and amplified by polymerase chain reaction(PCR) on 735 base pairs fragment of TNF-g gene with NcoI polymorpnic site. 735 bp PCR product was digested with NcoI restriction endonuclease, then analyzed by agarose gel electrophoresis to detect the NcoI restriction fragment length polymorphism(RFLP). The TNF-g alleles were divided into two types according to the electrophoresis patterns. TNF-b*1 allele, which contains the Ncol restriction site(CCATGG), should be digested 539 bp and 196 bp fragments. On the other hand, TNF-g*2 allele, which lacks the restriction site, only showed 735 bp fragment. RESULTS: Six out of 38(15.8%) IDDM patients were homozygous for the TNF-b*1 allele, 11(28.9%) were homozygous for the TNF-b*2 alleie, and 21 (55.3%) were TNF-b*1/*2 heterozygous compared to 21.7%, 30.7% and 49.3%(p=0.83), respectively, in control subjects. CONCLUSION: The TNF-b gene polymorphism was not associated with insulin-dependent diabetes mellitus in Korean subjects.

• Keywords: Tumor necrosis factor(TNF)-beta;Restriction Fragment Length polymorphism(RFLP);HLA;Insulin-dependent diabetes mellitus(IDDM);