PTPN1 and schizophrenia: The review synthesizes recent advances in understanding how dysregulation of specific PTPs, including PTP1B, PTP receptor gamma (PTPRG), PTPN5 (encoding striatal-enriched PTP [STEP]), and PTP receptor type A (PTPRA), contributes to disrupted synaptic signaling, neurotransmitter dysfunction, and neurodevelopmental abnormalities observed in schizophrenia.