Association between Clock T3111C and T257G gene polymorphisms and sleep epilepsy in a Hunan Han population

Objective To investigate the association between the Clock T3111C and T257G gene polymorphisms and sleep epilepsy patients in Han population of Hunan province. Methods Three hundred and eleven subjects with epilepsy(sleep epilepsy group(n=112), aperiodic group(n=95), awakening epilepsy group(n=104)) and 300 sex- and age-matched healthy controls were enrolled in the study. Genomic DNAs were extracted from peripheral blood leucocytes by phenol-chloroform methods. The Clock T3111C and T257G polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP). Results (1) Two genotypes(TT and TC) were detected in Clock T3111C. The frequency of Clock site T3111C genotypes in all of the people was 86.09%(TT，526/611), 13.91%(TC,85/611), 0(CC), T allele gene frequency was 93.04%(1134/1222) and C allele gene frequency was 6.96%(85/1222). There was no significant difference in genotype and gene distribution of Clock gene T3111C polymorphism between sleep epilepsy group, aperiodic group, awakening epilepsy group and control group.(2)Two genotypes(TT and TG) were detected in Clock T257G. The frequency of Clock site T257G genotypes in all of the people was 85.92%(TT,525/611), 14.08%(TG,86/611), 0(GG), T allele gene frequency was 92.96% (1136/1222) and G allele gene frequency was 7.04%(86/1222). There was no significant difference in genotype and gene distribution of Clock gene T257G polymorphisms between sleep epilepsy group, aperiodic epilepsy group, awakening epilepsy group and control group.(3)There was an almost complete correspondence(complete linkage disequilibrium) of bases between the positions 257 and 3111. Conclusion Clock gene T3111C and T257G polymorphisms are not associated with sleep epilepsy in Han population of Hunan province. Key words: Circadian rhythm; CLOCK proteins; Epilepsy; Polymorphism;  single nucleotide