Objective    To investigate the relationship between Lys198Asn and

Taq

Ⅰ polymorphisms of endothelin-1 gene and essential hypertension in Chongqing residents.     Methods    Polymorphisms of Lys198Asn and

Taq

Ⅰ were detected in the blood samples from 86 patients with essential

hypertension (HT) and 138 normotensive controls (NT) by sequence specific primer-polymerase chain reaction (SSP-PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP).     Results    In the BMI

<

25 kg/m

2

subjects

the frequency of GG and GA+AA of

Taq

Ⅰ  was 26 (72.2%) and 10 (27.8%) respectively in hypertensive group

28 (50.0%) and 28 (50.0%) respectively in normotensive group. Logistic regression model analysis showed that the GG carriers of

Taq

Ⅰ had a significant high risk to develop hypertension (

P

=0.037

OR

=2.597）in BMI

<

25 kg/m

2

subjects. The liner regression model analysis demonstrated that there was a significant difference in systolic blood pressure (SBP) between GG and GA+AA in BMI 

<

25 kg/m

2

subjects (

P

=0.018). SBP of the GG carriers (145.06 mmHg) were 13.09 mmHg higher than those of GA+AA carriers (131.97 mmHg).     Conclusion    Among the BMI

<

25 kg/m

2

 subjects

those with GG carriers of

Taq

Ⅰ  might be prone to have higher SBP. The GG genotype might be a risk factor for hypertension in normoweight subjects.