Project description:MicroRNA (miRNA) biomarkers for fragile X syndrome were searched by urine microRNA (miRNA) profiling using deep sequencing. The urine miRNA profile of twin boys who shared the same environment but one had a FXS full mutation and the other carried a premutation allele was compared based on the similar sequence reads. The urine of twin boys showed 28 differentiatially regulated miRNAs when 219 reliable identified miRNAs were compared.