Cause and Cure Discovered for Common Type of High Blood Pressure

A newly identified gene variant, present in harmless nodules in 5% of individuals suffering from hypertension, triggers the excessive production of the aldosterone hormone, resulting in high blood pressure. This condition can be effectively treated through the surgical removal of one adrenal gland, termed unilateral adrenalectomy. The research emphasizes the necessity for a 24-hour urine test for more accurate diagnosis and treatment of hypertension by measuring aldosterone levels.

Researchers at Queen Mary University of London and Barts Hospital have pinpointed a gene variant responsible for a prevalent type of high blood pressure, along with a cure for the condition, as indicated by a study published in Nature Genetics.

The source of the problem is a small, benign nodule, occurring in one out of twenty hypertension sufferers. This nodule generates aldosterone, a hormone that regulates the body’s salt content. The groundbreaking discovery is a gene variant within some of these nodules that causes sporadic yet extensive overproduction of this hormone.

This gene variant introduces multiple challenges that complicate the diagnosis of some hypertension patients. Firstly, the variant impacts a protein known as CADM1, preventing cells from signaling each other to halt aldosterone production. Additionally, the hormone’s erratic release throughout the day, causing salt overloads and hypertension at peak times, makes the diagnosis more challenging. This sporadic release explains why patients with this gene variant may evade diagnosis unless blood tests are conducted at various times throughout the day.

Aldosterone, a mineralocorticoid hormone produced by the adrenal cortex (the outer layer of the adrenal gland), plays a vital role in maintaining the body’s water and salt balance. It does so by encouraging sodium retention and potassium excretion in the kidneys. Nevertheless, an aldosterone surplus can lead to high blood pressure and fluid accumulation in body tissues.

Moreover, the scientists found that this type of hypertension can be cured by unilateral adrenalectomy, the removal of one adrenal gland. Post-surgery, the formerly severe hypertension disappeared, despite previous treatment with multiple medications, and no further treatment was necessary for several following years.

Aldosterone as a potential cause is not routinely measured, thus fewer than 1% of people with aldosterone-induced hypertension are identified. The team of researchers recommends using a 24-hour urine test, rather than single-time blood measurements, to diagnose more individuals living with undiagnosed hypertension.

The study’s initial participant was identified when doctors observed fluctuations in his hormone levels during a clinical trial for difficult hypertension treatments.

In most hypertension cases, the cause remains unknown, necessitating lifelong medication. Previous research by the Queen Mary team revealed that 5-10% of hypertension cases are due to a gene mutation in the adrenal glands, leading to excessive aldosterone production. This excess causes the body to retain salt, thereby raising blood pressure. Patients with high aldosterone levels are resistant to commonly used hypertension drugs and are at a higher risk of heart attacks and strokes.

Co-senior author of the study, Professor Morris Brown from Queen Mary University of London, shared:

“On the 900th anniversary of Barts Hospital, this discovery underscores the reciprocal benefits of Science and Medicine. Most patients agree to our non-routine molecular analysis of their surgical samples, enabling us to understand the cause of their hypertension and devise future cures. Since the aldosterone nodules in this study were tiny, we’re exploring whether temporary cauterization of the nodule could be an alternative to removing the entire adrenal gland.”

The Queen Mary research received funding from Barts Charity and was conducted by research fellows funded by the British Heart Foundation, National Institute of Health Research, Medical Research Council, and Royal Society. The team collaborated with labs in Munich, Paris, and Michigan to find more individuals with the new variant

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More about High Blood Pressure Gene Variant Discovery and Cure

• Nature Genetics
• Queen Mary University of London
• Barts Hospital
• Understanding Blood Pressure Readings
• Hormone Health Network on Aldosterone
• National Institute of Health Research
• British Heart Foundation
• Medical Research Council
• Royal Society
• Understanding Adrenalectomy