Gordon's syndrome (also known as pseudohypoaldosteronism type II or familial hyperkalaemic hypertension) is an extremely rare condition caused by single mutations in any one of four currently identified genes. It can be transmitted by either parent.
Its effects can vary from mild to more severe. When the condition is diagnosed, genetic testing of other family members is also offered. However, patients have been diagnosed with Gordon’s syndrome without any family history to account for it, as the mutations can arise spontaneously at the point of conception.
Currently there are thought to be between 20 and 30 families in the UK where Gordon’s syndrome has been diagnosed. Worldwide, there are known to be somewhere between 150 and 200 families involved.
Gordon’s syndrome is usually suspected in childhood or early adulthood if high levels of potassium (hyperkalaemia) are detected at a blood test, along with metabolic acidosis (a chemical imbalance in the blood) and hyperchloridaemia (high levels of chloride ion). If the diagnosis is made later, when patients are in their teens or older, an additional finding of high blood pressure may be present. Some more severe forms of the disease may also be associated with small or absent incisor teeth, shorter than expected stature, delayed cognitive development and joint problems.
There are two principle treatments for Gordon’s syndrome. One is following a low salt diet and this is really important. The other is taking thiazides, such as Bendroflumethiazide or Hydrochlorothiazide, or thiazide-like diuretics, such as Indapamide. The choice of which of these to prescribe would be made on a patient by patient basis.
The treatment is usually very successful and the prognosis is good. Both the blood pressure and the potassium come down with salt reduction and thiazide therapy and the metabolic acidosis also resolves. Early diagnosis is key because developmental problems can be driven by untreated metabolic acidosis. Both the salt reduction and thiazide therapy will be required for life but, with these in place, a long and otherwise healthy life can be anticipated.
Following initial diagnosis and treatment, patients are usually seen in a specialist clinic once a year lifelong with any additional monitoring undertaken by the GP or local specialist if they come from outside the area.