A novel de novo missense variant in ASH1L associated with mild autism spectrum disorder and an uneven cognitive profile: a case report

This case expands the known phenotypic spectrum of ASH1L-related disorders, demonstrating that a de novo missense variant can be associated with a milder neurodevelopmental phenotype, including borderline-to-average intellectual ability. These findings challenge suggestions that missense variants uniformly lead to more severe outcomes and underscores the importance of comprehensive genomic and deep clinical characterization to refine our understanding of gene-disease relationships.