A Novel KMT5B Frameshift Variant Presenting with Autism and Psychiatric Features: Intrafamilial Phenotypic Variation – A Case Report

By presenting a novel <i>KMT5B</i> variant alongside an atypical adult neuropsychiatric presentation, this report broadens both the variant and phenotypic spectrum of <i>KMT5B</i> haploinsufficiency. It further underscores the potential for neurobehavioral manifestations to extend beyond childhood, advocating for sustained clinical surveillance and age-spanning neuropsychiatric assessment.