What is Gitelman’s Syndrome ?

Gitelman’s syndrome is a rare inherited defect in the renal tubule of the kidneys.  This defect causes the kidney to waste magnesium, sodium, potassium and chloride in the urine, instead of reabsorbing it back into the bloodstream.   Urine calcium levels are lower than normal, despite normal serum values.   This syndrome does not cause kidney failure nor does it cause the kidneys to function abnormally.  The kidneys are normal.  The problem is the reabsorption of important electrolytes and minerals.

Difference between Gitelman’s and Bartter’s

Gitelman’s syndrome like Bartter’s is a renal salt wasting disorder but the defective tubule is in the thiazide-sensitive Na-Cl cotransporter in the distal convoluted tubule(DCT).

Gitelman’s Syndrome is an inherited disorder of the tubules of the kidney. Autosomal Recessive means that one gene came from the father and one gene came from the mother.  Gitelman’s is an autosomal recessive disorder. Read more about genetics.

The Defect

The defect is in the Thiazide Co-Transporter which is where Sodium, Potassium and Magnesium are absorbed into the body.  Because of the defect these minerals are lost in the urine instead of being absorbed in the body. The Thiazide co- transporter is also where thiazide diuretics take their action.  This is why many doctors will test their patients for the use of diuretics first before coming to the conclusion that this patient has Gitelman’s.  It is not that your doctor does not believe you but these type of medications can mock Gitelman’s.

Also for an unknown reason patients with Gitelman’s will hold on to calcium, which is why their urine shows a low calcium level.  This is one benefit of the syndrome and should protect the patient from getting osteoporosis.

Later Manifestation

Gitelman’s syndrome is characterized by a milder and later clinical presentation. Often, this disorder is diagnosed in asymptomatic ( No symptoms) adults who present with unexplained hypokalemia( Low serum potassium levels) .  In many cases the patient will go to the doctor for something else and when routine labwork is done it is found that this patient has low potassium levels.  In other cases the patient is having symptoms but doesn’t know what is wrong.  The majority of symptoms that these patients have are from the low Magnesium and Potassium levels.  These symptoms are listed below.

Pediatric Cases

Pediatric cases typically present in the school age period with fatigue, muscle weakness, and symptoms of neuromuscular irritability (Muscle cramps, leg cramps). Growth retardation and polyuria-polydipsia (Increased thirst and Increased urination) are not prominent features of Gitelman’s syndrome according to the literature but our survey has found that many Gitelman patients do have the polyuria and polydipsia.  So I have included this to the list of symptoms below. Joint pain secondary to chondrocalcinosis has been described in this subset of patients and attributed to the hypomagnesemia.

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