Salt Supplementation in Gitelman Syndrome

Exploratory Study Into the Effect of Salt Supplementation in Gitelman Syndrome

The purpose of this study is to determine the effect of salt (NaCl) supplementation on serum potassium and clinical signs and symptoms in patients with Gitelman syndrome.

Single subject multiple randomized double-blinded multi-crossover placebo-controlled trials (N-of-1 trials) will be performed. Participants will enroll the study after giving written informed consent. The individual trials will consist of 3 treatment blocks which each contain a 4-week treatment period of salt supplementation (12 grams of NaCl) and a 4-week treatment period of placebo, in a randomized, blinded order. After each period of 4 weeks, outcomes measures will be measured.

Inclusion Criteria:

• Genetically-proven, symptomatic Gitelman syndrome
• Written informed consent

Exclusion Criteria:

• inability to discontinue potassium-sparing diuretics, mineralocorticoid antagonists and NSAIDs; this means inability to reach a potassium level of 2.5 mmol/L or higher with maximally tolerable potassium supplementation after discontinuation of potassium-sparing diuretics
• pregnancy