Familial Hyperaldosteronism Type 2

Autosomal dominant primary aldosteronism caused by germline CLCN2 mutations.

Written by: Saygı Hospital Health Guide Editorial Board

Last updated: June 11, 2026

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Endokrinoloji department. Book Appointment →

What is Familial Hyperaldosteronism Type 2?

Familial hyperaldosteronism type 2 (FH-II) is a rare autosomal dominant disorder of aldosterone overproduction. Unlike FH-I, it does not respond to dexamethasone suppression. Germline CLCN2 mutations are recognized in a subset of cases.

Patients show variable phenotypes ranging from bilateral adrenal hyperplasia to unilateral aldosterone-producing adenomas. Pedigrees with multiple affected first-degree relatives are characteristic.

Diagnosis requires confirmation of primary aldosteronism (elevated aldosterone-to-renin ratio with positive confirmatory testing), exclusion of FH-I by genetic testing of CYP11B1/CYP11B2 chimeric gene, and detection of CLCN2 mutation when available.

Symptoms

Resistant hypertension at young age

Hypokalemia symptoms (weakness, cramps)

Headache and palpitations

Polyuria and nocturia

Family history of early hypertension

Stroke or cardiovascular events in young relatives

Risk Factors

First-degree relative with FH-II

Pathogenic CLCN2 variant

Early-onset hypertension in family

History of unexplained hypokalemia

Adrenal adenomas in pedigree

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

Resistant hypertension before age 40
Spontaneous or diuretic-induced hypokalemia
Multiple young relatives with hypertension
Stroke or atrial fibrillation at early age
Adrenal incidentaloma with hypertension

Treatment Methods

Mineralocorticoid receptor antagonists (spironolactone or eplerenone)

Adrenalectomy in unilateral aldosterone-producing adenoma

Genetic counseling and CLCN2 testing of relatives

Lifestyle measures: low-sodium diet, weight control

Long-term blood pressure and electrolyte monitoring

Cardiovascular risk-factor optimization

Which Department to Visit?

You can visit our Endokrinoloji department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.