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Kidney Week

Abstract: PO1622

Recurrent SLC12A3 Mutations in Taiwanese Families with Gitelman Syndrome: A Rapid Detection for the Higher Prevalence

Session Information

Category: Genetic Diseases of the Kidneys

  • 1002 Genetic Diseases of the Kidneys: Non-Cystic

Authors

  • Lin, Shih-Hua P., Division of Nephrology, Tri-Service General Hospital, Taipei, Taiwan
  • Yang, Sung-Sen, Division of Nephrology, Tri-Service General Hospital, Taipei, Taiwan
  • Sung, Chih-Chien, Division of Nephrology, Tri-Service General Hospital, Taipei, Taiwan
  • Tseng, Min-hua, Division of Pediatrics, Tao-yang, Taiwan
Background

Recurrent mutations in SLC12A3 gene responsible for autosomal recessive Gitelman syndrome (GS) are reported to be common with uncertain prevalence. Rapid detection of the recurrent hotspots may help early diagnosis of GS but remain challenging. We aim to investigate the prevalence of recurrent SLC12A3 mutations in a large Taiwan cohort of GS families and develop a simple, novel, and rapid method to detect recurrent SLC12A3 hotspots.

Methods

One hundred and thirty independent families with genetically-confirmed GS referred from different regions of Taiwan were consecutively enrolled to define recurrent SLC12A3 hotspots and determine their prevalence. Using Taqman MGB probe-based real time primer chain reaction (RT-PCR), hotspots-based mutational detection plate was designed and optimized to recognize all hotspots. We validated this mutation detection plate and also tested the feasibility in 12 newly-diagnosed GS patients.

Results

A total of 57 mutations in SLC12A3 gene were identified from our cohort and 22 different mutations including two deep intronic mutations were found in at least two unrelated families, comprising 85.7% of all allelic mutations including biallelic triple mutations. These 22 hotspots-based detetion plate was fully validated with excellent sensitivity and specificity in GS patients carrying biallelic SLC12A3 mutations and healthy subjects. In the clinical validation, recurrent mutations were recognized in 87.5% of allelic mutations of 12 newly-diagnosed GS patients within 4 hours and all confirmed by direct sequencing.

Conclusion

Recurrent SLC12A3 mutations are very common in Taiwanese GS patients. This novel hotspots-based detection plate may be time, cost, and labor saving to rapidly identify the recurrent hotspots and provide an early molecular diagnosis of GS in patients with chronic hypokalemia.