Current research has examined the overlap of genetic risk factors and phenotypic behaviors in Autism Spectrum Disorders (ASDs) and Schizophrenia (SZ). We compiled a table of functional groups of genes altered in both ASDs and SZ and grouped them based on function. We described several functional groups altered in both neurodevelopmental disorders including the dopamine pathway, signaling molecules, GABA and glutamate signaling, and endosomal proteins. Previous work has explored the roles of dopamine, signaling cascades, GABA and glutamate in these disorders. The purpose of this review is to analyze the endosomal pathway members implicated in both disorders. These genes include an endosomal solute carrier, endosomal GTPases, endosomal coat proteins and endosomal coatassociated proteins. Deeper understanding of the endosomal pathway could lead to the progress of biomarker development for ASDs and SZ, enhanced therapeutics, and greater knowledge of how specific molecular pathways contribute to neurodevelopmental disorders.