Liddle's Syndrome is a rare genetic pathology, the main symptoms of which are a low content of aldosterone in the blood and high blood pressure. In patients, reabsorption of sodium is increased and the content of potassium in the blood is lowered. Usually, the disease appears in children early, under the age of 4 years, but often asymptomatic. The disease was first described by American endocrinologist Grant Liddle in 1963. It was he who established the genetic nature of this pathology.
Causes
Liddle's syndrome is inherited in an autosomal dominant manner. The cause of the disease is a mutation in one of the four genes responsible for the operation of the epithelial sodium channels. These channels are present in especially large numbers in the epithelial cells of the kidneys, as well as in the cells of the brain and stomach. Epithelial sodium channels facilitate reabsorption of sodium by liver cells. As a result of mutations, these channels are constantly in the open state, which leads to increased reabsorption of sodium ions.
In people without a mutation, the constant presence of epithelial sodium channels indicates an increased secretion of aldosterone, since it is this hormone that takes part in regulating the position of the portal mechanism of the described channels. That is why this syndrome is called pseudo-hyperaldosteronism - the symptoms indicate an increased content of aldosterone in the blood, while in fact its concentration is lowered.
Epithelial sodium channels play an important role in maintaining normal blood pressure by maintaining a concentration gradient of sodium and potassium ions. Patients with pathologies of these channels have high blood pressure.
Symptoms
Liddle's syndrome is often asymptomatic. The first sign of the disease is high blood pressure in the child. If drugs to lower blood pressure are ineffective, then a further examination is necessary. Sick children often show increased fatigue, lagging behind peers in physical development against the background of hypokalemia.
The same symptoms are characteristic of primary hyperaldosteronism, therefore, laboratory studies are necessary to make the correct diagnosis.
Prevalence
Liddle's syndrome is extremely rare - less than 30 cases of the disease worldwide have been described according to 2008 data. The frequency of this pathology among men and women is the same.
Diagnostics
A diagnosis requires analysis of the level of renin and aldosterone in the blood. In patients, these indicators are significantly lower than normal, while at the same time, sodium reabsorption by the renal tubules is increased. To make an absolutely accurate diagnosis, it is recommended to conduct a genetic study that will show if there are mutations in the genes responsible for the operation of the epithelial sodium channels.
Treatment
Therapy includes a low-sodium diet and potassium-sparing diuretics that block sodium channels. Most often, patients are prescribed Triamteren or Amiloride. The drugs increase the release of sodium ions and reduce the release of potassium ions. "Amilorid" is allowed to be taken even during pregnancy, since the drug is non-toxic and has no negative effect on the fetus.
The medications described should be taken only at the doses indicated by your doctor, otherwise there is a risk of developing a sodium deficiency and a condition similar to secondary hyperaldosteronism.
The most radical way to treat this pathology, which is rarely used, is liver transplantation. After surgery, all symptoms of the disease disappear in patients .