Autism, currently known as Autism Spectrum Disorder (ASD), is a lifelong neuropsychiatric disorder that starts before three years of age. The behavioral and cognitive symptoms seem to be caused by an abnormal synaptic connectivity that leads to deficits in the ability, to filter sensor), information. Poor filtering seems to constitute a barrier for the integration and processing of neuronal information. Because ASD is not a neurodegenerative disorder, under appropriate conditions, symptoms usually improve overtime, probably because the autistic person learns to filter sensory information by alternative neuronal routes. This allows him/her to have a better understanding of the surrounding environment and in turn facilitates learning. Early intervention on children identified before age 2 notably improves prognosis. Currently, ASD can be detected in boys and girls when they are about 18 months old. However, parents and autism experts can observe symptoms before that age. The participation of the health system in order to prepare parents, pediatricians, and caregivers is highly important and leads to significant improvements in the quality, of life of autistic individuals and of caregivers.