Credit: Tohoku University Graduate School of Medicine Researchers at Tohoku University have revealed further insight into the fetal development of our brain and the potential causes of Fragile X syndrome (FSX). During brain development, the fetal period is vital in creating neurons from neural stem cells to build up a functional adult brain. Any impairment in the developmental program could result in severe defects in the brain. FSX is a genetic disorder characterized by intellectual disability and autistic symptoms. Children with FSX will generally suffer from developmental delays as well as social and behavioral problems. FSX patients have a defect in the fragile X mental retardation 1 (FMR1) gene, a gene that codes for the fragile X mental retardation protein (FNRP)--the critical factor in normal brain development.