SYN1 and Intellectual disability: Epilepsy, learning disabilities, speech delay, intellectual disability (ID), and autism spectrum disorder (ASD) are the most frequent clinical manifestations associated with SYN1 variants (Longhena et al. 2021; John et al. 2021; Accogli et al. 2021), but an extensive comparison of the clinical features and genotype-phenotype correlations are missing.