Project description

Parents of autistic children describe a sudden emergence of the autistic phenotype around 18 months old. This project will test this observation with a systematic review of prospective studies on autistic development across the first two years of life. Our objective is to characterize the sequence of appearance of repetitive, social and communicative signs, and the slope of their onset according to their severity and degree of difference to a non-autistic population. Thus, we will visualise the time these signs take to develop and the order in which they appear.

To study the onset of autistic signs, we will use longitudinal prospectives studies following newborn siblings of diagnosed autistics. These children have a 20% risk of developing autism spectrum disorder. These studies enable the monitoring of the children’s development since birth and the study of signs predictive of a later prototypical autistic presentation.120 studies have been identified using PRISMA protocol and 5 fixed inclusion criteria: original study, on high-risk children, reporting at least 2 measures, taken before 2 years old, and of which some will receive a diagnosis. Data collection is in process.

Based on hundreds of clinical observations, we hypothesize that a steep slope is linked to a subsequent prototypical autistic presentation. If this observation is confirmed by our systematic review, we propose that speed of emergence be integrated to the semiology of prototypical autism, enabling the identification of a clinically and longitudinally homogenous group within the current autism spectrum.