{Reference Type}: Case Reports {Title}: Case report: genetic analysis of a novel frameshift mutation in FMR1 gene in a Chinese family. {Author}: Jin C;Zhang X;Lei Q;Chen P;Hu H;Shen S;Liu J;Ye S; {Journal}: Front Genet {Volume}: 14 {Issue}: 0 {Year}: 2023 {Factor}: 4.772 {DOI}: 10.3389/fgene.2023.1228682 {Abstract}: 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 FMR1 (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 FMR1 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 FMR1 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.