Metabolic and structural causes were investigated and, finally, whole exome sequencing in trio identified a de novo heterozygous, probably pathogenic, variant c.545C>T (p.Thr182Ile) in the GNAO1 gene.<h4>Conclusions</h4>Early recognition of neurodevelopmental delay and abnormal movements are determinants of an etiological approach to a neurological disorder. This evidence concerns the gene GNAO1 and nervous system disorder.