A gene essential for normal brain development, and previously linked to Autism Spectrum Disorders, also plays a critical role in addiction-related behaviors, researchers report. The team used animal models to show that the fragile X mental retardation protein, or FMRP, plays a critical role in the development of addiction-related behaviors. FMRP is also the protein that is missing in Fragile X Syndrome, the leading single-gene cause of autism and intellectual disability.