Introduction:
Gitelman syndrome (GS) is caused by genetic mutation resulting in dysfunction of the thiazide-sensitive sodium-chloride cotransporter located in the distal convoluted tubule. The disease usually produces the first visible symptoms during adolescence or adulthood. This paper describes the case of a boy who developed the first symptoms at the age of 6 and was diagnosed when 16.

CASE REPORT:
At the time of admission of the 16-year-old boy, the following information was provided: the child suffered from upper limb muscle cramps recurring every few weeks since the age of six. Lower limb and orbicularis oris muscle cramps were also observed. In addition, during fever, the patient presented additional symptoms: numbness of the face and limbs. The patient was treated in an ED with anxiolytics and magnesium. Two weeks before admission he developed diarrhea and fever, followed the next day by severe muscle cramps with forced limb position and finally short term loss of consciousness. The boy was admitted to the local hospital where laboratory tests showed hypokalemia, hypomagnesemia and metabolic alkalosis, and then was transferred to the Clinic of Paediatric Nephrology. Blood tests confirmed earlier results and in addition revealed hypochloremia and increased plasma renin activity. The urine tests had following results: basic pH, decreased specific gravity, increased excretion of potassium and magnesium and reduced excretion of calcium. Blood pressure and abdomen USG were normal. Genetic testing was performed and two heterozygous mutations: 2221 G→A (Gly741Arg) and 1315 G→A (Gly439Ser) were found in the SLC12A3 gene.

CONCLUSIONS:
GS may occur early in life and produce only short passing episodes when symptoms are observable. The presence of the mentioned symptoms requires considering tubulopathy during diagnosis. If not diagnosed and not treated, GS may lead in the long term to somatic complications and a decreased quality of life.