Genetic testing for familial hyperaldosteronism type 1 in Aotearoa/New Zealand

Primary aldosteronism (PA) is the most common secondary endocrine cause of hypertension with familial hyperaldosteronism type 1 (FH-1), a rare heritable subtype. Timely identification of FH-1 is important because of an increased risk of vascular events in affected individuals and because it provides the opportunity to guide appropriate treatment. Genetic testing is recommended if onset is at a young age (<20 years), there is a family history of PA or early cerebrovascular events occur.

To assess national rates of testing for FH-1, whether this varied over time and by region.

De-identified data were obtained on genetic testing performed for FH-1 from 1 April 2010 to 30 October 2023 (163 months) from the Canterbury Health Laboratories database, the sole national testing laboratory for FH-1.

A total of 147 tests were performed, of which 19 (12.9%) were positive. Eleven of the positive tests were requested by one region. Testing rates varied from 0.00 to 0.63 per 100 000 people per annum. Most tests were requested by endocrinology services. Testing increased over time from an average of 4.6 tests per annum in the first 5 years of the period studied to 17.7 tests in the most recent 5 years. Limitations include lack of ethnicity data, information on testing indications and testing rates for other familial PA subtypes.

Testing for FH-1 has increased over time but remains low. Testing for familial forms of PA should be considered in those in whom PA was diagnosed at a young age or with a suggestive family history.