Bartter syndrome representing digenic-based salt-losing tubulopathies presumably accelerated by renal insufficiency
- PDF / 515,295 Bytes
- 5 Pages / 595.276 x 790.866 pts Page_size
- 67 Downloads / 152 Views
CASE REPORT
Bartter syndrome representing digenic‑based salt‑losing tubulopathies presumably accelerated by renal insufficiency Ryusuke Umene1,2 · Mineaki Kitamura2 · Hideyuki Arai1 · Kazuki Matsumura1 · Yuka Ishimaru1 · Kanenori Maeda3 · Tadashi Uramatsu2 · Yoko Obata2 · Takayasu Mori4 · Eisei Sohara4 · Shinichi Uchida4 · Tomoya Nishino2 Received: 6 April 2020 / Accepted: 12 May 2020 © Japanese Society of Nephrology 2020
Abstract Bartter syndrome and Gitelman syndrome (GS) are autosomal recessive disorders usually caused by homozygous or compound heterozygous mutations in causative genes. In some patients, these two syndromes cannot be discriminated based on clinical features or mutation type; thus, a single disease concept, salt-losing tubulopathies (SLTs), has been used instead. Despite the existence of several SLT causative genes, cases of digenic heterozygous mutations in two different genes are extremely rare. Here, we report the case of a 36-year-old woman with renal insufficiency and hypokalemia caused by an SLT. To evaluate the SLT phenotype, we performed next-generation sequencing (NGS) with a gene panel including SLC12A3, SLC12A1, CLCNKB, and CLCNKA as well as laboratory examinations and diuretic loading tests. The results of the diuretic loading tests were consistent with a GS phenotype, while the NGS results showed that the patient had heterozygous mutations in SLC12A1 and CLCNKB. Both genes have been associated with BS, suggesting that the SLT was caused by digenic heterozygous mutations in two different genes. To date, only a few SLT cases caused by digenic heterozygous mutations in two different genes have been reported. The digenic SLT phenotype in the patient was presumably accelerated by moderate renal insufficiency. Keywords SLC12A1 · CLCNKB · Bartter syndrome · Salt-losing tubulopathies
Introduction Bartter syndrome (BS) and Gitelman syndrome (GS) are autosomal recessive renal tubular salt-wasting disorders characterized by hypokalemia and metabolic alkalosis. BS usually develops in neonates or during childhood and has relatively severe symptoms, whereas GS is diagnosed in childhood and adulthood and has relatively mild symptoms. Type 3 BS often presents clinical features similar to GS and * Mineaki Kitamura mkitamura‑[email protected] 1
Department of Nephrology, JCHO Isahaya General Hospital, Nagasaki, Japan
2
Department of Nephrology, Nagasaki University School of Medicine Graduate School of Biomedical Sciences, 1‑12‑4 Sakamoto, Nagasaki 852‑8102, Japan
3
Ken-ai-kai Maeda Clinic, Nagasaki, Japan
4
Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
thus is difficult to distinguish from GS. Although the prevalence of hypomagnesemia and hypocalciuria is higher in GS than in BS, it is difficult to completely discriminate these two pathophysiologies; therefore, BS and GS have recently been regarded as a single disease: hereditary salt-losing tubulopathies (SLTs) [1, 2]. The SLT phenotype may vary depending
Data Loading...
