Figure 1Figure 1
Relationship between syndromic and non-syndromic ASD and their genetic underpinnings. The left circle represents syndromic ASD, where autism spectrum disorder (ASD) symptoms occur as part of a broader clinical syndrome. Examples include Angelman syndrome (UBE3A), Rett syndrome (MECP2), Fragile X syndrome (FMR1), Phelan-McDermid syndrome (SHANK3), and Tuberous Sclerosis Complex (TSC1, TSC2). In these cases, ASD is considered a component of the syndrome. The right circle represents non-syndromic ASD, characterized by isolated ASD without additional syndromic features. High-risk genes associated with non-syndromic ASD include CNTNAP2, GRIN2B, CHD8, SCN2A, PTEN, and SHANK3. Notably, SHANK3 mutations can also occur in ASD patients without Phelan-McDermid syndrome, indicating that a single gene mutation may lead to ASD alone. The overlapping region highlights shared molecular pathways, such as synapse formation, synaptic pruning, and ubiquitination, demonstrating that different genetic backg