Lack of mutations in epithelial sodium channel beta-subunit gene in human subjects with hypertension

Objective To investigate a possible role for mutations of the epithelial sodium channel in patients with essential hypertension. Design A cross-sectional study screening essential hypertension patients and normotensive controls for the presence of a genetic abnormality in the epithelial sodium channel beta-subunit in the Japanese population. Setting An institutional teaching hospital. Patients and participants Ninety Japanese patients with essential hypertension and 51 normotensive controls were investigated. The hypertensive patients were consecutive samples from our hypertension clinics. It was required that they had had a previous history of systolic blood pressure higher than 160 mmHg or diastolic higher than 95 mmHg. Secondary hypertension was excluded by clinical presentation or appropriate laboratory examinations. Normotensive subjects were patients visiting our outpatient clinics without evidence or a history of hypertension, It was required that they had systolic blood pressures less than 160 mmHg and diastolic blood pressures less than 90 mmHg, and that they were aged above 60 years. Interventions Genomic DNA from each subject was purified from whole blood and was used as the template for polymerase chain reaction amplification of the carboxyterminal portion of the epithelial sodium channel beta-subunit. Amplified DNA segments were screened for genetic mutations by direct sequencing. Main outcome measure Genetic mutations of the epithelial sodium channel beta-subunit. Results No significant genetic mutation was detected in any of the hypertensive and normotensive subjects, except for a polymorphism found in three subjects (two hypertensives and one normotensive). Conclusion Mutations of the carboxy-terminal portion of the epithelial sodium channel beta-subunit were not identified in an unselected cohort of patients with essential hypertension from the Japanese community.