Large Deletion Leading to Fragile X Syndrome.

Fragile X syndrome (FXS) is the most frequent cause of X-linked inherited intellectual disabilities (ID) and the most frequent monogenic form of autism spectrum disorders. It is caused by an expansion of a CGG trinucleotide repeat located in the 5'UTR of the gene, resulting in the absence of the fragile X mental retardation protein, FMRP. Other mechanisms such as deletions or point mutations of the gene have been described and account for approximately 1% of individuals with FXS. Here, we report a 7-year-old boy with FXS with a deletion of approximately 1.1 Mb encompassing several genes, including the and the genes, and several miRNAs, whose lack of function could result in the observed proband phenotypes. In addition, we also demonstrate that completely overlaps with , and there are no sequencing differences between both transcripts (i.e., throughout the article).