The authors present a case of 56 years old female patient with anamnestic pain in knee joints, cramps and limbs paresthesia, with detected steady low serum levels of potassium and magnesium and metabolic alkalosis. High renal losses of both elements as well as hypocalciuria were detected. Radiographic examination gave evidence of knee joints chondrocalcinosis. Genetic examination proved the presence of homozygous point mutation in exon 10 of gene SLC12A3, which leads to change of glycine to serine at position 439 of cotransport protein NCTT. This mutation has already been repeatedly described in Gitelman syndrome. Gitelman syndrome comes under tubulopathies causing hypokalemia and is related to Bartter syndrome. Both diseases are linked to hypokalemia, renal losses of potassium, metabolic alkalosis and the activation of reninangiotensin- aldosterone axis. In contrast to Bartter syndrome, the individuals with Gitelman syndrome have significant hypomagnesemia, hypermagnesiuria, hypocalciuria and milder clinical development with manifestation in higher age. The possible link between this syndrome and chondrocalcinosis appears interesting for a rheumatologist. In case of mentioned female patient, the therapy based on primarily massive parenteral, subsequently continual peroral substitution of potassium and magnesium and application of spironolactone and indomethacin led to total clinical symptom reduction and partial correction of laboratory values.

        Key words: Gitelman syndrome, hypokalemia, hypomagnesemia, chondrocalcinosis