Monogenic Forms of Low-Renin Hypertension

Vesna D Garovic; Anthony A Hilliard; Stephen T Turner


Nat Clin Pract Nephrol. 2006;2(11):624-630. 

In This Article

Familial Hyperaldosteronism Type II

Initially described in 1991 in 13 patients from five families whose primary hyperaldosteronism was not suppressed by a dexamethasone challenge (distinguishing it from FH-I), familial hyperaldosteronism type II (FH-II) is now recognized as another rare cause of secondary hypertension.[10] Patients with FH-II are clinically indistinguishable from those with sporadic forms of primary hyperaldosteronism due to bilateral adrenal hyperplasia. The genetic abnormality causing FH-II has been localized to chromosome 7p22.[11] In patients with a family history of hypertension who present with hypertension and hypokalemia, one should consider screening for genetic causes of primary hyperaldosteronism.

While both FH-I and FH-II are rare, it is important to differentiate between the two causes of familial hyperaldosteronism as they require vastly different treatments. Direct genetic testing for the presence of the chimeric gene is available and has been shown to have 100% sensitivity and specificity for diagnosing FH-I.[12] In FH-I, glucocorticoids ameliorate overproduction of aldosterone, thus diminishing ACTH release and subsequently blood pressure. By contrast, hypertension in FH-II is unresponsive to glucocorticoids, but spironolactone is effective.


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