The Effect Of CYP2C9 SNP On The Warfarin's Stable Doses Of 30 Chinese Mongolian Heart Disease Patients

Background and objectionWarfarin is a kind of common anticoagulant for mechanical prosthetic valve replacement. It has troubled many clinicians for many years that Warfarins individual stable dose differentiates in large scale, its therapeutic index is very small and unsuitable anticoagulant treatment can easily cause hazardous clinical complications. Cytochrome P450 is the main oxidative enzyme of Warfarin. One of its coding gene, CYPs subfamily CYP2C9 has the phenomenon of SNP (Single nucleotide polymorphism). This kind of single nucleotide difference can significantly lower the enzyme activity of Cytochrome P450, therefore cause the significant difference of Warfarin's stable dose in different individual. By now, the SNP of CYP2C9 in Caucasians has many reports, but the study on the SNP of Mongolians'CYP2C9 is still in incipient stage, and has many controversies.On the basis of above mentioned study results, this article wants to identify whether the 30 Chinese Mongolians that were recruited in this study have the same genetic mutations, hope to find some different mutations not mentioned in previous articles also.Materials and Methods1. Objects: 30 patients after mechanical prosthetic valve replacement were recruited, male 16, female 14, mean weight 64.7 5.26kg, INR in 2.0 ~2.5. All of them had no the conditions that could affect Warfarin's metabolism.2. Methods: Took 1.0ml venous blood from every recruited patient, extrac-ted DNA with TaKaRa whole blood Genome kit, PCR amplified the objective fragments of exon3, exon4 and exon7, genotyped all the amplified fragments.Statistic AnalysisAll the data were expressed as mean value 卤 standard deviation. Statistical significance was determined by t test and X2analysis.Results1. The number of PCR amplified and genotyped fragments was 90, successful rate was 100 %.2. In 30 fragments of amplified exonS, the detecting frequency of homozy-gous CGT( Arg144) on site 416 was 100 % , the one of heterozygous 416CGT > TGT( Argl44Cys) was 0. In 30 fragments of amplified exon7, the detecting frequency of heterozygous 1061 ATT > CTT(Ile359Leu) was 0, and the one of ho-mozygous 1061ATT(Ile359) was 100 %. In 30 fragments of amplified exon4, the detecting frequencies of heterozygous 608 TTG > GTG(Leu208Val) and 527 ATT>CTT(Ilel81Leu) were 100 % respectively, the ones of homozygous 561CAG (Glui92) and 537CAT(His184) were 100 % respectively, the ones of heterozygous 561 GAG > CCG( Glul92Pro) and 537CAT > CCT( Hisl84Pro) were 0 respectively. 7 samples appeared heterozygous 584AAA >TGG( Arg200Trp) , detecting frequency was 23.3 %.3. Arranged 30 patients into 2 groups on the basis of suspected mutation on site 584 of exon4. With statistic treatment, the Warfarin's stable dose of non -mutation group was 47. 06 12. 82jxg/kg d, the one of suspected mutation group was 26. 81 9. 74g/kg d, there was significant variance between 2 groups(P <0.01). On the basis of the difference of individual stable dose, arrange 30 patients into high dose, media dose and low dose 3 groups. X2 analysis suggested the superior genotype of 3 dose groups had significant variance (P <0. 01).DiscussionCytochrome P450 is a kind of main oxidative enzyme for many endogenous and extrogenous substrates. Its coding gene CYP has subfamily phenomenon, CYP2C9s SNP can significantly affect cytochrome P450 activity. By now, the SNP of Caucasians 'CYP2C9 has many reports, but the one of Mongolians 'is still in controversy.In this study, with 30 patients genotyped, results suggested; the detecting frequency of heterozygous 416CGT >TGT was 0, which agreed on the study results of TakahashiiB. The genotyping results of exon4 were significantly different with the one of Anskar Y. H. ' s. 23. 3 % of exon4 had been suspected having 584 AAA > TGG mutation. With Warfarin ' s stable dose of the patients ' , statistic analysis suggested the stable dose of suspected 5 84 AAA > TGG mutation group had significant variance (P <0. 01 ) compared with that of non - mutation group. A...