Diagnostic strategy for inherited hypomagnesemia

• Published in: Clinical and experimental nephrology 2017-12, Vol.21 (6), p.1003-1010
• Main Authors: Horinouchi, Tomoko, Nozu, Kandai, Kamiyoshi, Naohiro, Kamei, Koichi, Togawa, Hiroko, Shima, Yuko, Urahama, Yoshimichi, Yamamura, Tomohiko, Minamikawa, Shogo, Nakanishi, Keita, Fujimura, Junya, Morioka, Ichiro, Ninchoji, Takeshi, Kaito, Hiroshi, Nakanishi, Koichi, Iijima, Kazumoto
• Format: Article
• Language: English
• Subjects: Adult; Calcium-sensing receptors; Child; Child, Preschool; Female; Genes; Genetic counseling; Genetic screening; Humans; Hypercalciuria - diagnosis; Hypercalciuria - genetics; Hypomagnesemia; Infant; Male; Medicine; Medicine & Public Health; Nephrocalcinosis - diagnosis; Nephrocalcinosis - genetics; Nephrology; Original Article; Renal Tubular Transport, Inborn Errors - diagnosis; Renal Tubular Transport, Inborn Errors - genetics; Transient receptor potential proteins; Urology; Young Adult
• ISSN: 1342-1751; 1437-7799
• DOI: 10.1007/s10157-017-1396-7

Background Hereditary hypomagnesemia is difficult to diagnose accurately because of its rarity and the variety of causative genes. We established a flowchart for identifying responsible genes for hypomagnesemia, and we confirmed its diagnostic efficacy in patients with suspected inherited hypomagnesemia. Methods We established a flowchart and applied it to five index cases with suspected inherited hypomagnesemia. Direct sequence analysis was used to detect the causative gene variants in four cases, and targeted sequencing analysis using next-generation sequencing (NGS) of all causative genes for hypomagnesemia was used in one. Results Expected pathogenic variants were detected in the HNF1B, TRPM6, CLDN16, CASR , or SLC12A3 gene in all five cases. The results of all genetic analyses were consistent with the clinical diagnostic results using the flowchart. Conclusions Accurate genetic diagnosis is crucial for estimating the prognosis, detecting complications in organs other than the kidneys, and for directing genetic counseling. The developed flowchart for identifying responsible genes for hypomagnesemia was useful for diagnosing inherited hypomagnesemia. In addition, NGS analysis will help to resolve clinical difficulties in making an accurate diagnosis and thus improve the diagnostic strategy for inherited hypomagnesemia.