Scientists at The Scripps Research Institute (TSRI) are giving researchers a first look at the early stages of brain development in patients with Fragile X syndrome, a disorder that causes mild to severe intellectual disability and is the most common genetic cause of autism spectrum disorder. The disorder is triggered when the Fragile X Mental Retardation (FMR1) gene on the X chromosome is epigenetically silenced. Symptoms are hyperactivity, seizures, intellectual disability,delayed speech, and problems with social interactions.
The research team used their expertise with induced pluripotent stem cells (iPSCs) and used samples from juveniles and adults with Fragile X syndrome to induce the cells to become neurons in a lab dish. They observed that the Fragile X cells had delayed development in formation of neuronal synapses, the brain’s message centers. The scientists also discovered a second, more surprising aspect of the syndrome. The mutation on the X chromosome appeared to trigger genome-wide changes to DNA modifications.