Gitelman syndrome

Gitelman syndrome
Classification and external resources
ICD-10	N25.8 + E87.6 + E83.4
OMIM	263800
DiseasesDB	31860
eMedicine	article/238670
MeSH	D053579

Gitelman syndrome is a rare inherited defect in the distal convoluted tubule of the kidneys. It causes the kidneys to pass sodium, magnesium, chloride, and potassium into the urine, rather than allowing it to be resorbed into the bloodstream.

Gitelman syndrome is not to be confused with Bartter syndrome, which is a rare inherited defect in the thick ascending limb of the loop of Henle.

Cause

A model of transport mechanisms in the distal convoluted tubule. Sodium-chloride (NaCl) enters the cell via the apical thiazide-sensitive NCC and leaves the cell through the basolateral Cl- channel (ClC-Kb), and the Na+/K+-ATPase. Indicated also are the recently identified magnesium channel TRPM6 in the apical membrane, and a putative Na/Mg exchanger in the basolateral membrane. These transport mechanisms play a role in familial hypokalemia-hypomagnesemia or Gitelman's syndrome.

Gitelman syndrome has an autosomal recessive pattern of inheritance.

Gitelman's syndrome is linked to inactivating mutations in the SLC12A3 gene resulting in a loss of function of the encoded thiazide-sensitive sodium-chloride co-transporter (NCCT). This cell membrane protein participates in the control of ion homeostasis at the distal convoluted tubule portion of the nephron.

Gitelman's syndrome is an autosomal-recessive disorder: one defective allele has to be inherited from each parent.

Presentation

People suffering from Gitelman's syndrome present symptoms which are identical to those of patients who are on thiazide diuretics

Clinical symptoms for this disease are hypochloremic metabolic alkalosis, hypokalemia, and hypocalciuria. Hypomagnesemia is present in many but not all cases. In contrast to patients with Gordon's syndrome, those suffering from Gitelman's syndrome are generally normotensive. Carriers of Gitelman's syndrome-linked mutations are often asymptomatic while some complain of mild muscular cramps or weakness expressed as fatigue or irritability. More severe symptoms such as tetany and paralysis have however also been reported. Phenotypic variations observed among patients probably result from differences in their genetic background and may depend on which particular amino acid in the NCCT protein has been mutated.

See Naesens et al. for a recent review.

Eponym

It is named for Hillel Gitelman.

External links

• The Bartter Site