Nature Communications, Published online: 29 May 2026; doi:10.1038/s41467-026-73881-9 Antisense oligonucleotides targeting the glycine transporter SLC6A20 restore NMDA -receptor function and rescue behavioral and synaptic phospho-proteomic deficits in Shank2- and Shank3-mutant mice and in human SHANK2/SHANK3 cortical organoids.