Association of the glutathione S-transferase M1 homozygous null genotype with susceptibility to Sjogren's syndrome in Japanese individuals

Objective. To investigate the role of polymorphisms of the glutathione S-tr ansferase M1 (GSTM1) and GSTT1 genes in determining susceptibility to Sjogr en's syndrome (SS) and autoantibody production. Methods, Polymorphisms of the GSTM1 and GSTT1 genes in 106 Japanese patient s with primary SS and in 143 healthy controls were analyzed by polymerase c hain reaction. Results. Frequency of the GSTM1 homozygous null genotype was significantly increased in SS patients compared with controls (57.5% versus 44.1%; P = 0. 035). Moreover, a significantly greater frequency of SSA antibodies was fou nd among SS patients with the GSTM1 null genotype than among those with the GSTM1 non-null genotype (P = 0.0013). Frequency of the GSTT1 polymorphism was not different between SS patients and controls. Conclusion. The GSTM1 homozygous null genotype could be a genetic factor th at determines susceptibility to SS and may be involved in SSA antibody prod uction.