A case analysis of Gitelman syndrome complicated with Sjögren's disease.

BACKGROUND

Sjögren's disease (an autoimmune exocrinopathy) and Gitelman syndrome (an autosomal recessive renal tubulopathy caused by SLC12A3 mutations) both manifest with hypokalemia. Their coexistence can significantly complicate differential diagnosis.

METHODS

A 62-years-old female presented with fatigue, dry mouth, and refractory hypokalemia. Immunological testing (positive antinuclear and anti-centromere protein B antibodies) and a labial gland biopsy confirmed Sjögren's disease. However, her severe hypokalemia was disproportionate to Sjögren's-induced renal tubular acidosis alone. Genetic analysis revealed compound heterozygous pathogenic mutations in SLC12A3: c.1196G > A (p.Arg399His) and c.1732G > A (p.Val578Met), confirming concurrent Gitelman syndrome.

RESULTS

Combined therapy with potassium supplementation and hydroxychloroquine successfully resolved symptoms and stabilized serum potassium levels.

CONCLUSION

In Sjögren's disease patients with refractory hypokalemia, underlying hereditary renal tubular disorders should be suspected. Combining immunological evaluation with genetic testing is crucial to ensure accurate diagnosis and optimize management.