The evidence from recent surveys on chronic pancreatitis carried out around the world shows that alcohol remains the main factor associated with chronic pancreatitis, even if at a frequency lower than that reported pr...The evidence from recent surveys on chronic pancreatitis carried out around the world shows that alcohol remains the main factor associated with chronic pancreatitis, even if at a frequency lower than that reported previously. It has further conf irmed that heavy alcohol consumption and smoking are independent risk factors for chronic pancreatitis. Autoimmune pancreatitis accounts for 2%-4% of all forms of chronic pancreatitis, but this frequency will probably increase over the next few years. The rise in idiopathic chronic pancreatitis, especially in India, represents a black hole in recently published surveys. Despite the progress made so far regarding the possibility of establishing the hereditary forms of chronic pancreatitis and the recognition of autoimmune pancreatitis, it is possible that we are more inaccurate today than in the past in identifying the factors associated with chronic pancreatitis in our patients.展开更多
AIM:To evaluate the association between p53 codon 72 polymorphism and liver cancer risk by means of meta-analysis. METHODS:Two investigators independently searched the Medline,Embase and Chinese Biomedicine databases....AIM:To evaluate the association between p53 codon 72 polymorphism and liver cancer risk by means of meta-analysis. METHODS:Two investigators independently searched the Medline,Embase and Chinese Biomedicine databases.Summary odds ratios and 95%CI for p53 codon 72 polymorphism and liver cancer were calculated in fixedeffects model(Mantel-Haenszel method)and randomeffects model(DerSimonian and Laird method)when appropriate. RESULTS:This meta-analysis included 1115 liver cancer cases and 1778 controls.The combined results based on all studies showed that there was a statistically significant link between Pro/Pro genotype and liver cancer,but not between Arg/Arg or Pro/Arg genotype and liver cancer.When stratifying for race,similar results were obtained,i.e.patients with liver cancer had a significantly higher frequency of Pro/Pro genotype than non-cancer patients among Asians.After stratifying thevarious studies by control source,gender,family history of liver cancer and chronic hepatitis virus infection,we found that(1)patients among hospital-based studies had a significantly higher frequency of Pro/Pro and a significantly lower frequency of Arg/Arg genotype than individuals without cancer;(2)female patients with liver cancer had a significantly lower frequency of Arg/Arg and a higher frequency of Pro/Arg+Pro/Pro genotypes than female individuals without cancer;(3)subgroup analyses for family history of liver cancer did not reveal any significant association between p53 codon 72 polymorphism and liver cancer development;and(4) patients with negative hepatitis virus infection had a significantly higher frequency of Pro/Pro and a significantly lower frequency of Arg/Arg genotype than individuals without cancer. CONCLUSION:This meta-analysis suggests that the p53 codon 72 polymorphism may be associated with liver cancer among Asians.展开更多
AIM:To investigate the association between interleukin-28B(IL28B) genotype and response to treatment and hepatic fibrosis in patients with hepatitis C virus(HCV) genotype 4.METHODS:Two hundred and one HCV-genotype 4 p...AIM:To investigate the association between interleukin-28B(IL28B) genotype and response to treatment and hepatic fibrosis in patients with hepatitis C virus(HCV) genotype 4.METHODS:Two hundred and one HCV-genotype 4 patients were included.All patients were treated with Peginterferon alph2a/Ribavirin for 48 wk.End of treatment response(ETR) was defined as loss of detectable serum HCV RNA at the end of treatment.Sustained viral response(SVR) was defined as loss of detectable serum HCV RNA at the end of 24 wk follow up.Genotyping of IL28B rs12979860 was performed using the TaqMan assay.We used logistic regression to estimate the adjusted odds ratio(aOR) and 95%CI.RESULTS:The study included 201 HCV-genotype 4 patients.The majority of patients were men(89.6%),with a median age of 47 years,inter-quartile range(40-51).Approximately 62.5% of patients had ETR,and 49.6% had SVR.Individuals who achieved SVR were more likely to be younger(χ 2 = 4.91,P = 0.027),and less likely to have fibrosis(χ 2 = 15.54,P < 0.0001),or inflammation(χ 2 = 7.58,P = 0.006).The genotype distribution of rs12979860 was 36.2%,49.0% and 14.8% for genotypes CC,CT,and TT,respectively.In these participants,rs12979860 genotype distribution did not differ by gender(P = 0.466),pretreatment viral load(P = 0.600),inflammation(P = 0.435),or fibrosis(P = 0.291).The frequencies of IL28B rs12979860 genotypes were TT(14.8%),CT(49.0%),and CC(36.2%).Compared to rs12979860 genotype TT,aORs(95%CI) for ETR and SVR were:CC genotype,[17.55(5.34-57.69) and 5.92(2.09-16.76),respectively];CT genotype,[5.15(1.80-14.78) and 2.48(0.94-6.52),respectively].In the current study,the patients who did not achieve ETR or SVR had a lower prevalence of rs12979860 CC(17.4% and 23.3%,respectively) than individuals who had ETR or SVR(47.9% and 47.2%,respectively).Individuals with rs12979860 CC genotype had approximately 6 times the odds of SVR compared to individuals with TT genotype(aOR = 5.92;95%CI:2.09-16.76).Similarly,patients with CT genotype had SVR more often than patients with TT genotype(aOR = 2.48;95%CI:0.94-6.52).Carrying at least one copy of the C allele(genotypes CT and CC) had almost 8 times the probability of ETR compared to those with genotype rs12979860 TT(aOR = 7.87;95%CI:2.84-21.82),and approximately 3 times the odds of SVR compared to those with genotype rs12979860 TT(aOR = 3.46;95%CI:1.37-8.74).In addition,data were consistent with a significant gene-dose relationship(aOR = 4.05/allele;95%CI:2.27-7.22).The association between rs12979860 genotype and SVR was similar among those who achieved and those who did not achieve SVR.CONCLUSION:In HCV-genotype 4 patients,rs12979860 is a sensitive predictor of viral clearance,independent of viral load,age,gender or fibrosis,with no similar relation to severity of fibrosis.展开更多
Objective: To investigate the association of Graves’ disease and Graves’ ophthalmopathy with the C/T transition polymorphism at position –318 of promoter and the A/G transition polymorphism at position 49 of exon 1...Objective: To investigate the association of Graves’ disease and Graves’ ophthalmopathy with the C/T transition polymorphism at position –318 of promoter and the A/G transition polymorphism at position 49 of exon 1 within cytotoxic T lymphocyte associated antigen-4 (CTLA-4) gene. Methods: Thirty-three patients with ophthalmopathy of Graves’ disease, fifty-six Graves’ patients without ophthalmopathy and sixty normal subjects as control were involved in the present case-control study. The polymorphisms were evaluated by polymerase chain reaction fragment length polymorphism (PCR-RFLP). Com-parisons were made of gene frequencies and allele frequencies between the groups. Results: The gene frequencies of CT and allele frequencies of T were much higher in Graves’ patients with ophthalmopathy than that in the group without ophthalmopathy (P=0.020, P=0.019). The gene frequencies of GG and allele frequencies of G in patients with Graves’ disease were significantly increased as compared with control group (P=0.008, P=0.007). The data suggest that smokers with Graves’ disease seemed to be more predisposed to ophthalmopathy than non-smokers (P=0.018). Conclusion: Our results suggest that an allele of T at position –318 of promoter is associated with genetic susceptibility to Graves’ ophthalmopathy while an allele of G at position 49 of exon 1 is associated with genetic susceptibility to Graves’ disease instead. Smoking is believed to be a major risk factor for ophthalmo-pathy.展开更多
Objective To investigate the association between the polymorphism of C-689T in the peroxisome proliferator-activated receptor-γ2 (PPARγ2) promoter and coronary heart disease (CHD). Methods This case-controlled...Objective To investigate the association between the polymorphism of C-689T in the peroxisome proliferator-activated receptor-γ2 (PPARγ2) promoter and coronary heart disease (CHD). Methods This case-controlled study was conducted in nondiabetic Chinese Han people, which enrolled 455 patients with CHD (cases) and 693 subjects without CHD (controls). Data of clinical indexes were collected, including height, body weight, waist circumstance, systolic blood pressure (SBP), diastolic blood pressure (DBP), smoking, drinking, physical activity, as well as body mass index (BMI). Fasting blood glucose (FBG), plasma total cholesterol (TC) and triglyceride (TG) levels were measured. Polymerase chain reaction-restricted fragments length polymorphism (PCR-RFLP) was used to determine the PPARγ2 promoter C-689→T substitution. The genotype distribution of PPARγ2 promoter C-689T, allelic frequency, clinical indexes, and laboratorial measurements were compared between the two groups. The effect of genotype on the risk of CHD was assessed using univariate and multivariate regression model. Results The genotype frequencies of CC, CT and TT in PPARγ2 promoter C-689T were 89.7%, 9.9% and 0.4% in the case group, and 93.1%, 6.6% and 0.3% in the control group, respectively (CC vs. CT+TT, χ^2= 6.243, P=0.041). Carriers of -689T allele (n=95) had significantly higher TC level than non-carriers (n=1053) (5.12±1.26 vs. 4.76±1.22 mmol/L, P=0.001). Male carriers of -689T allele (n=51) were significantly higher in waist circumference, body weight, TC and TG than male non-carriers (n=656) (all P〈0.05). In subjects whose BMI was over 25 kg/m2, carriers of -689T allele (n=82) had significantly higher levels of waist circumference, BMI, SBP and TC than non-carriers (n=231) (all p〈0.05). The -689T allele was an independent risk factor for CHD (OR=1.668, 95%CI: 1.031-2.705, P=0.037) after adjusting for age, gender, waist circumference, body weight, BMI, smoking, physical activities, SBP, DBP, FBG, TC and TG level. Conclusion These data support the hypothesis that the -689T allele is associated with an increased risk of CHD, in Chinese Han people and correlates significantly with the profiles of CHD-related risk factors.展开更多
Objective: The aim in this study was to identify the allelicfrequencies of the chemokine (SDF1-3'A) and chemokinereceptor (CCR5△32, CCR5m303 and CCR2-64I) genesresistant to HIV-1 infection and/or disease progress...Objective: The aim in this study was to identify the allelicfrequencies of the chemokine (SDF1-3'A) and chemokinereceptor (CCR5△32, CCR5m303 and CCR2-64I) genesresistant to HIV-1 infection and/or disease progression inindigenous Chinese populations. Methods: By using QIAamp DNA Blood Mini Kit, thegenomic DNA samples were purified from whole peripheralblood of healthy individuals (n=2067) from Han, Uygur,Mongolian and Tibetan ethnic groups, as well as Han patientsincluding HIV-1 carriers (n=330), patients with other sexuallytransmitted diseases (STDs, n=259) and intravenous drugusers (IVDUs, n=125). The allelic polymorphisms wereidentified by means of PCR or PCR-RFLP analyses. Thesequences of randomly selected amplified PCR products werefurther confirmed by direct DNA sequencing. Results: The mutant frequencies were identified to be0%~3.48% for CCR5△32, 0% for CCR5m303,19.15%~28.79% for CCR2-64 and 19.10%~28.73% for SDF1-3'A alleles, respectively, in Chinese healthy individuals fromfour ethnic groups. Our findings indicated the allelicfrequencies vary among the different ethnic groups.Furthermore, the HIV-1 carriers, STD cases and IVDUs (all ofHan ethnicity) were found to have the allelic frequencies of0%~0.19% (CCR5△32), 0% (CCR5m303), 19.31%~20.45%(CCR2-64) and 25.61%~26.83% (SDF1-3'A) with minorvariations in their frequencies between the patients andhealthy Han groups. There was no CCR5-m303 mutationfound in any subject in this study. Conclusion: The examined subjects of four Chinese ethnicorigins showed lower frequencies of CCR5△32 andCCR5m303 alleles, but higher frequencies of mutant CCR2-64I and SDF1-3'A alleles compared to those identified innorthern-European and American Caucasians. Thesignificance of the different frequencies and polymorphisms ofthe above alleles in Chinese populations needs to be furtherexamined in HIV-1/AIDS diseases.展开更多
Knowledge of the geographic distribution and frequency of avirulence genes will contribute to the development of strategies to effectively use rice varieties that carry various resistances genes, including combination...Knowledge of the geographic distribution and frequency of avirulence genes will contribute to the development of strategies to effectively use rice varieties that carry various resistances genes, including combinations of varieties in mixture cropping systems. Here, we analyzed the geographic distribution and frequencies of avirulence genes in rice blast fungus using samples collected from 11 prefectures across Yunnan province, China. A total of 467 single spore isolates were assayed for pathotypes based on their reaction to 20 rice blast resistance monogenic lines. The results revealed that frequencies of avirulence genes among 10 prefectures showed insignificant difference, but frequencies of avirulenee genes in Xishuangbanna showed significant differences compared to the remaining 10 prefectures. The avirulence genes Avr-Pi9, Avr-Piz and Avr-Pizt were observed at the highest frequency in blast isolates from the 11 prefectures; their average frequency was greater than 80%. Our results imply that the composition and distribution of rice genetic diversity are more important than climate and other environment conditions for formation and maintenance of rice blast fungus genetic diversity. Using average frequencies, the avirulence genes can be categorized into 4 groups. There were significant differences of frequencies of avirulence genes among different groups, while insignificant differences observed within any group. These results will provide useful information for evaluation of resistance genes and effective management of rice blast disease.展开更多
文摘The evidence from recent surveys on chronic pancreatitis carried out around the world shows that alcohol remains the main factor associated with chronic pancreatitis, even if at a frequency lower than that reported previously. It has further conf irmed that heavy alcohol consumption and smoking are independent risk factors for chronic pancreatitis. Autoimmune pancreatitis accounts for 2%-4% of all forms of chronic pancreatitis, but this frequency will probably increase over the next few years. The rise in idiopathic chronic pancreatitis, especially in India, represents a black hole in recently published surveys. Despite the progress made so far regarding the possibility of establishing the hereditary forms of chronic pancreatitis and the recognition of autoimmune pancreatitis, it is possible that we are more inaccurate today than in the past in identifying the factors associated with chronic pancreatitis in our patients.
文摘AIM:To evaluate the association between p53 codon 72 polymorphism and liver cancer risk by means of meta-analysis. METHODS:Two investigators independently searched the Medline,Embase and Chinese Biomedicine databases.Summary odds ratios and 95%CI for p53 codon 72 polymorphism and liver cancer were calculated in fixedeffects model(Mantel-Haenszel method)and randomeffects model(DerSimonian and Laird method)when appropriate. RESULTS:This meta-analysis included 1115 liver cancer cases and 1778 controls.The combined results based on all studies showed that there was a statistically significant link between Pro/Pro genotype and liver cancer,but not between Arg/Arg or Pro/Arg genotype and liver cancer.When stratifying for race,similar results were obtained,i.e.patients with liver cancer had a significantly higher frequency of Pro/Pro genotype than non-cancer patients among Asians.After stratifying thevarious studies by control source,gender,family history of liver cancer and chronic hepatitis virus infection,we found that(1)patients among hospital-based studies had a significantly higher frequency of Pro/Pro and a significantly lower frequency of Arg/Arg genotype than individuals without cancer;(2)female patients with liver cancer had a significantly lower frequency of Arg/Arg and a higher frequency of Pro/Arg+Pro/Pro genotypes than female individuals without cancer;(3)subgroup analyses for family history of liver cancer did not reveal any significant association between p53 codon 72 polymorphism and liver cancer development;and(4) patients with negative hepatitis virus infection had a significantly higher frequency of Pro/Pro and a significantly lower frequency of Arg/Arg genotype than individuals without cancer. CONCLUSION:This meta-analysis suggests that the p53 codon 72 polymorphism may be associated with liver cancer among Asians.
基金Supported by Hamad Hospital-HMC and Qatar UniversityHealth Sciences-Biomedical Labssponsored by HMC
文摘AIM:To investigate the association between interleukin-28B(IL28B) genotype and response to treatment and hepatic fibrosis in patients with hepatitis C virus(HCV) genotype 4.METHODS:Two hundred and one HCV-genotype 4 patients were included.All patients were treated with Peginterferon alph2a/Ribavirin for 48 wk.End of treatment response(ETR) was defined as loss of detectable serum HCV RNA at the end of treatment.Sustained viral response(SVR) was defined as loss of detectable serum HCV RNA at the end of 24 wk follow up.Genotyping of IL28B rs12979860 was performed using the TaqMan assay.We used logistic regression to estimate the adjusted odds ratio(aOR) and 95%CI.RESULTS:The study included 201 HCV-genotype 4 patients.The majority of patients were men(89.6%),with a median age of 47 years,inter-quartile range(40-51).Approximately 62.5% of patients had ETR,and 49.6% had SVR.Individuals who achieved SVR were more likely to be younger(χ 2 = 4.91,P = 0.027),and less likely to have fibrosis(χ 2 = 15.54,P < 0.0001),or inflammation(χ 2 = 7.58,P = 0.006).The genotype distribution of rs12979860 was 36.2%,49.0% and 14.8% for genotypes CC,CT,and TT,respectively.In these participants,rs12979860 genotype distribution did not differ by gender(P = 0.466),pretreatment viral load(P = 0.600),inflammation(P = 0.435),or fibrosis(P = 0.291).The frequencies of IL28B rs12979860 genotypes were TT(14.8%),CT(49.0%),and CC(36.2%).Compared to rs12979860 genotype TT,aORs(95%CI) for ETR and SVR were:CC genotype,[17.55(5.34-57.69) and 5.92(2.09-16.76),respectively];CT genotype,[5.15(1.80-14.78) and 2.48(0.94-6.52),respectively].In the current study,the patients who did not achieve ETR or SVR had a lower prevalence of rs12979860 CC(17.4% and 23.3%,respectively) than individuals who had ETR or SVR(47.9% and 47.2%,respectively).Individuals with rs12979860 CC genotype had approximately 6 times the odds of SVR compared to individuals with TT genotype(aOR = 5.92;95%CI:2.09-16.76).Similarly,patients with CT genotype had SVR more often than patients with TT genotype(aOR = 2.48;95%CI:0.94-6.52).Carrying at least one copy of the C allele(genotypes CT and CC) had almost 8 times the probability of ETR compared to those with genotype rs12979860 TT(aOR = 7.87;95%CI:2.84-21.82),and approximately 3 times the odds of SVR compared to those with genotype rs12979860 TT(aOR = 3.46;95%CI:1.37-8.74).In addition,data were consistent with a significant gene-dose relationship(aOR = 4.05/allele;95%CI:2.27-7.22).The association between rs12979860 genotype and SVR was similar among those who achieved and those who did not achieve SVR.CONCLUSION:In HCV-genotype 4 patients,rs12979860 is a sensitive predictor of viral clearance,independent of viral load,age,gender or fibrosis,with no similar relation to severity of fibrosis.
文摘Objective: To investigate the association of Graves’ disease and Graves’ ophthalmopathy with the C/T transition polymorphism at position –318 of promoter and the A/G transition polymorphism at position 49 of exon 1 within cytotoxic T lymphocyte associated antigen-4 (CTLA-4) gene. Methods: Thirty-three patients with ophthalmopathy of Graves’ disease, fifty-six Graves’ patients without ophthalmopathy and sixty normal subjects as control were involved in the present case-control study. The polymorphisms were evaluated by polymerase chain reaction fragment length polymorphism (PCR-RFLP). Com-parisons were made of gene frequencies and allele frequencies between the groups. Results: The gene frequencies of CT and allele frequencies of T were much higher in Graves’ patients with ophthalmopathy than that in the group without ophthalmopathy (P=0.020, P=0.019). The gene frequencies of GG and allele frequencies of G in patients with Graves’ disease were significantly increased as compared with control group (P=0.008, P=0.007). The data suggest that smokers with Graves’ disease seemed to be more predisposed to ophthalmopathy than non-smokers (P=0.018). Conclusion: Our results suggest that an allele of T at position –318 of promoter is associated with genetic susceptibility to Graves’ ophthalmopathy while an allele of G at position 49 of exon 1 is associated with genetic susceptibility to Graves’ disease instead. Smoking is believed to be a major risk factor for ophthalmo-pathy.
文摘Objective To investigate the association between the polymorphism of C-689T in the peroxisome proliferator-activated receptor-γ2 (PPARγ2) promoter and coronary heart disease (CHD). Methods This case-controlled study was conducted in nondiabetic Chinese Han people, which enrolled 455 patients with CHD (cases) and 693 subjects without CHD (controls). Data of clinical indexes were collected, including height, body weight, waist circumstance, systolic blood pressure (SBP), diastolic blood pressure (DBP), smoking, drinking, physical activity, as well as body mass index (BMI). Fasting blood glucose (FBG), plasma total cholesterol (TC) and triglyceride (TG) levels were measured. Polymerase chain reaction-restricted fragments length polymorphism (PCR-RFLP) was used to determine the PPARγ2 promoter C-689→T substitution. The genotype distribution of PPARγ2 promoter C-689T, allelic frequency, clinical indexes, and laboratorial measurements were compared between the two groups. The effect of genotype on the risk of CHD was assessed using univariate and multivariate regression model. Results The genotype frequencies of CC, CT and TT in PPARγ2 promoter C-689T were 89.7%, 9.9% and 0.4% in the case group, and 93.1%, 6.6% and 0.3% in the control group, respectively (CC vs. CT+TT, χ^2= 6.243, P=0.041). Carriers of -689T allele (n=95) had significantly higher TC level than non-carriers (n=1053) (5.12±1.26 vs. 4.76±1.22 mmol/L, P=0.001). Male carriers of -689T allele (n=51) were significantly higher in waist circumference, body weight, TC and TG than male non-carriers (n=656) (all P〈0.05). In subjects whose BMI was over 25 kg/m2, carriers of -689T allele (n=82) had significantly higher levels of waist circumference, BMI, SBP and TC than non-carriers (n=231) (all p〈0.05). The -689T allele was an independent risk factor for CHD (OR=1.668, 95%CI: 1.031-2.705, P=0.037) after adjusting for age, gender, waist circumference, body weight, BMI, smoking, physical activities, SBP, DBP, FBG, TC and TG level. Conclusion These data support the hypothesis that the -689T allele is associated with an increased risk of CHD, in Chinese Han people and correlates significantly with the profiles of CHD-related risk factors.
基金This project was supported by grant from National Natural Sciences Foundation of the PR China(39770683)
文摘Objective: The aim in this study was to identify the allelicfrequencies of the chemokine (SDF1-3'A) and chemokinereceptor (CCR5△32, CCR5m303 and CCR2-64I) genesresistant to HIV-1 infection and/or disease progression inindigenous Chinese populations. Methods: By using QIAamp DNA Blood Mini Kit, thegenomic DNA samples were purified from whole peripheralblood of healthy individuals (n=2067) from Han, Uygur,Mongolian and Tibetan ethnic groups, as well as Han patientsincluding HIV-1 carriers (n=330), patients with other sexuallytransmitted diseases (STDs, n=259) and intravenous drugusers (IVDUs, n=125). The allelic polymorphisms wereidentified by means of PCR or PCR-RFLP analyses. Thesequences of randomly selected amplified PCR products werefurther confirmed by direct DNA sequencing. Results: The mutant frequencies were identified to be0%~3.48% for CCR5△32, 0% for CCR5m303,19.15%~28.79% for CCR2-64 and 19.10%~28.73% for SDF1-3'A alleles, respectively, in Chinese healthy individuals fromfour ethnic groups. Our findings indicated the allelicfrequencies vary among the different ethnic groups.Furthermore, the HIV-1 carriers, STD cases and IVDUs (all ofHan ethnicity) were found to have the allelic frequencies of0%~0.19% (CCR5△32), 0% (CCR5m303), 19.31%~20.45%(CCR2-64) and 25.61%~26.83% (SDF1-3'A) with minorvariations in their frequencies between the patients andhealthy Han groups. There was no CCR5-m303 mutationfound in any subject in this study. Conclusion: The examined subjects of four Chinese ethnicorigins showed lower frequencies of CCR5△32 andCCR5m303 alleles, but higher frequencies of mutant CCR2-64I and SDF1-3'A alleles compared to those identified innorthern-European and American Caucasians. Thesignificance of the different frequencies and polymorphisms ofthe above alleles in Chinese populations needs to be furtherexamined in HIV-1/AIDS diseases.
基金supported by the National Natural Science Fund (30860161)National Basic Research Program (No. 2011CB100400)The Ministry of Science and Technology of China,the Natural Science Fund (2010ZC173)
文摘Knowledge of the geographic distribution and frequency of avirulence genes will contribute to the development of strategies to effectively use rice varieties that carry various resistances genes, including combinations of varieties in mixture cropping systems. Here, we analyzed the geographic distribution and frequencies of avirulence genes in rice blast fungus using samples collected from 11 prefectures across Yunnan province, China. A total of 467 single spore isolates were assayed for pathotypes based on their reaction to 20 rice blast resistance monogenic lines. The results revealed that frequencies of avirulence genes among 10 prefectures showed insignificant difference, but frequencies of avirulenee genes in Xishuangbanna showed significant differences compared to the remaining 10 prefectures. The avirulence genes Avr-Pi9, Avr-Piz and Avr-Pizt were observed at the highest frequency in blast isolates from the 11 prefectures; their average frequency was greater than 80%. Our results imply that the composition and distribution of rice genetic diversity are more important than climate and other environment conditions for formation and maintenance of rice blast fungus genetic diversity. Using average frequencies, the avirulence genes can be categorized into 4 groups. There were significant differences of frequencies of avirulence genes among different groups, while insignificant differences observed within any group. These results will provide useful information for evaluation of resistance genes and effective management of rice blast disease.