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Evidence for heritability of non-modulating essential hypertension.
R P Lifton1, P N Hopkins, R R Williams
1Endocrine-Hypertension Unit, Brigham and Women's Hospital, Boston, MA 02115.
Hypertension (Dallas, Tex. : 1979)
|June 1, 1989
Summary
Essential hypertension patients with a family history of the condition show impaired blood pressure regulation. This "non-modulation" is linked to genetic predisposition, suggesting hereditary factors in hypertension development.
Area of Science:
- Nephrology
- Cardiovascular Medicine
- Human Genetics
Background:
- Essential hypertension is a complex condition with multifactorial etiology.
- A subset of hypertensive individuals exhibits blunted renal and adrenal responses to sodium and angiotensin II.
- Family history is a known risk factor for hypertension, suggesting a genetic component.
Purpose of the Study:
- To investigate the relationship between family history of hypertension and the ability to modulate renal vascular reactivity.
- To determine if impaired reactivity to angiotensin II (Ang II) and sodium is associated with a positive family history (FH+) of hypertension.
- To assess the prevalence and concordance of non-modulation in hypertensive siblings.
Main Methods:
- Studied renal blood flow responses to infused Ang II and dietary sodium changes in 13 unselected hypertensive subjects with detailed family histories.
- Classified subjects as 'modulators' or 'non-modulators' based on established criteria.
- Investigated Ang II responses in 31 hypertensive siblings from 14 sibships to assess concordance and prevalence of non-modulation.
Main Results:
- Subjects with a positive family history (FH+) demonstrated significantly smaller decrements in renal blood flow in response to Ang II compared to FH- subjects (p=0.024).
- FH+ subjects showed attenuated renal blood flow increases with increased dietary sodium intake versus FH- subjects (p=0.014).
- All seven non-modulators were FH+, and 81% of hypertensive siblings studied were non-modulators, with significant concordance observed between sibling pairs (p=0.004).
Conclusions:
- Non-modulation of renal vascular reactivity is strongly associated with a positive family history of hypertension.
- These findings suggest a significant genetic influence on the impaired vascular and adrenal responses observed in some hypertensive individuals.
- The high prevalence and concordance of non-modulation in siblings point towards heritable factors in hypertension pathogenesis.