Autism spectrum disorder (ASD) is a long-known complex neurodevelopmental disorder, and over the past decades, with the enhancement of the research genomic techniques, has been the object of intensive research activity, and many genes involved in the development and functioning of the central nervous system have been related to ASD genesis. Herein, we report a patient with severe ASD carrying a G > A de novo variant in the FGFR2 gene, determining a missense mutation. FGFR2 encodes for the ubiquitous fibroblast growth factor receptor (FGFR) type 2, a tyrosine kinase receptor implicated in several biological processes. The mutated version of this protein is known to be responsible for several variable overlapping syndromes. Even if there still is only sparse and anecdotal data, recent research highlighted a potential role of FGFR2 on neurodevelopment. Our findings provide new insights into the potential causative role of FGFR2 gene in complex neurodevelopmental disorders.