Objective To investigate the relationship of four single nucleotide polymorphism （SNP） haplotypes in the angiotensinogen （AGT） gene to the primary hypertension with or without cerebral infarction in the Li nationality of Hainan, China. Methods Total 300 subjects were allocated into three different groups： Groupl, 100 patients who have primary hypertension; Group 2, 100 patients who have primary hypertension with cerebral infarction; and control group, 100 healthy individuals. The genotypes of all subjects were determined by PCR-sequencing to analyze the four poly- morphisms at position - 152 （G-A）, -20 （A-C）, - 18 （C-T）, and -6 （A-G） in the promoter region of AGT. Results The frequen- cies ofCT genotype of AGT-18 and T allele in Group 1 （P = 0.003, P = 0.004） and Group 2 （P = 0.002, P = 0.002） were both significantly higher than in healthy controls. The frequency of G allele of AGT-6 was significantly higher in Group 2 than in the control group （P = 0.016）, while there is no significant difference between Group 1 and the control. Haplotype analysis revealed that H6 haplotype frequency which included -20C and -6G was significantly increased in Group 2 （P = 0.003） compared with the control group, while H5 haplotype frequency which included -20C and -18T was signifi- cantly increased in Group 1 （P = 0.006） versus the control. Conclusion The -20 （A-C） and - 18 （C-T） of the AGT may play an important role in pathogenesis of primary hypertension; and -20 （A-C）, -18 （C-T）, and -6 （A-G） may be the genetic risk factors for the onset of primary hypertension with cerebral infarction in the Li nationality of Halnan, China.
