Jin Chunlei, Zhang Xiangdong, Lei Qiang, Chen Penglong, Hu Hui, Shen Shuangshuang, Liu Jiao, Ye Shixuanbao
Center of Medical Prenatal Diagnosis, Lishui Maternity and Child Health Care Hospital, Lishui, China.
Center of Medical Prenatal Diagnosis, Jinhua Maternity and Child Health Care Hospital, Jinhua, China.
Front Genet. 2023 Sep 7;14:1228682. doi: 10.3389/fgene.2023.1228682. eCollection 2023.
Fragile X syndrome (FXS) [OMIM 300624] is a common X-linked inherited syndrome with an incidence only second to that of trisomy 21. More than 95% of fragile X syndrome is caused by reduced or absent fragile X intellectual disability protein 1 (FMRP) synthesis due to dynamic mutation expansion of the CGG triplet repeat in the 5'UTR and abnormal methylation of the (fragile X messenger ribonucleoprotein 1) gene [OMIM 309550]. Less than 5% of cases are caused by abnormal function of the FMRP due to point mutations or deletions in the gene. In a proband with clinical suspicion of FXS and no CGG duplication, we found the presence of c.585_586del (p.Lys195AsnfsTer8) in exon 7 of the gene using whole exome sequencing (WES). This variant resulted in frameshift and a premature stop codon after 8 aberrant amino acids. This variant is a novel pathogenic mutation, as determined by pedigree analysis, which has not been reported in any database or literature.
脆性X综合征(FXS)[OMIM 300624]是一种常见的X连锁遗传性综合征,发病率仅次于21三体综合征。超过95%的脆性X综合征是由于5'UTR中CGG三联体重复序列的动态突变扩展以及FMR1(脆性X信使核糖核蛋白1)基因的异常甲基化导致脆性X智力低下蛋白1(FMRP)合成减少或缺失所致[OMIM 309550]。不到5%的病例是由于FMR1基因的点突变或缺失导致FMRP功能异常引起的。在一名临床怀疑患有FXS且无CGG重复的先证者中,我们使用全外显子组测序(WES)在FMR1基因的第7外显子中发现了c.585_586del(p.Lys195AsnfsTer8)。该变异导致移码,并在8个异常氨基酸后出现提前终止密码子。经家系分析确定,该变异是一种新的致病突变,尚未在任何数据库或文献中报道。