Zhao Xiangzhong, Cui Li, Lang Yanhua, Liu Ting, Lu Jingru, Wang Cui, Tuffery-Giraud Sylvie, Bottillo Irene, Wang Xinsheng, Shao Leping
Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao 266555, China.
Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China.
Sci Rep. 2016 Sep 26;6:33920. doi: 10.1038/srep33920.
Familial renal glycosuria (FRG) is caused by mutations in the SLC5A2 gene, which codes for Na-glucose co-transporters 2 (SGLT2). The aim of this study was to analyze and identify the mutations in 16 patients from 8 families with FRG. All coding regions, including intron-exon boundaries, were analyzed using PCR followed by direct sequence analysis. Six mutations in SLC5A2 gene were identified, including five missense mutations (c.393G > C, p.K131N; c.1003A > G, p.S335G; c.1343A > G, p.Q448R; c.1420G > C, p.A474P; c.1739G > A, p.G580D) and a 22-bp deletion in intron 7 (c.886(-10_-31)del) removing the putative branch point sequence. By the minigene studies using the pSPL3 plasmids, we confirmed that the deletion c.886(-10_-31)del acts as a splicing mutation. Furthermore, we found that this deletion causes exclusion of exon 8 in the SCL5A2 transcript in patients. The mutation c.886(-10_-31)del was present in 5 (62.5%) of 8 families, and accounts for about 37.5% of the total alleles (6/16). In conclusion, six mutations resulting in FRG were found, and the c.886(-10_-31)del may be the high frequency mutation that can be screened in FRG patients with uniallelic or negative SLC5A2 mutations.
家族性肾性糖尿（FRG）由SLC5A2基因突变引起，该基因编码钠-葡萄糖协同转运蛋白2（SGLT2）。本研究旨在分析并鉴定8个患有FRG的家族中16例患者的突变情况。使用聚合酶链反应（PCR）随后进行直接序列分析，对包括内含子-外显子边界在内的所有编码区域进行分析。在SLC5A2基因中鉴定出6个突变，包括5个错义突变（c.393G＞C，p.K131N；c.1003A＞G，p.S335G；c.1343A＞G，p.Q448R；c.1420G＞C，p.A474P；c.1739G＞A，p.G580D）以及内含子7中的一个22碱基对缺失（c.886(-10_-31)del），该缺失去除了假定的分支点序列。通过使用pSPL3质粒进行的小基因研究，我们证实缺失c.886(-10_-31)del作为一个剪接突变起作用。此外，我们发现该缺失导致患者SCL5A2转录本中外显子8的缺失。突变c.886(-10_-31)del存在于8个家族中的5个（62.5%），约占总等位基因的37.5%（6/16）。总之，发现了6个导致FRG的突变，并且c.886(-10_-31)del可能是在具有单等位基因或阴性SLC5A2突变的FRG患者中可进行筛查的高频突变。
