Autism Spectrum Disorder (ASD) presents a complex puzzle. While recent genetic advances have identified genes linked to ASD, the vast variation in symptoms (phenotypic heterogeneity) among individuals remains a mystery. This is particularly puzzling in simplex autism, where only one child in a family is affected. Despite a seemingly simpler genetic background, these cases still display a surprising range of symptoms. This work delves into this very mystery. By analyzing genetic data and phenotypic traits in simplex autism cohorts, researchers aim to uncover the link between specific gene mutations and the severity of ASD symptoms. This in-depth exploration has the potential to shed light on why individuals with similar genetic mutations can exhibit such diverse characteristics. The findings could pave the way for a deeper understanding of the underlying causes of ASD heterogeneity and ultimately lead to more personalized treatment approaches