DRD4 and schizophrenia: Therefore, any genetic variations in these receptor genes alter the dopaminergic neurotransmission in the brain and increase the susceptibility to various neuropsychiatric disorders like autism spectrum disorder (ASD) (dopamine receptor D1), schizophrenia (dopamine receptor D3), Parkinson’s disease (dopamine receptor D3 and dopamine receptor D4), and paranoid schizophrenia (dopamine receptor D5) (Kim et al., 2009; Zhao et al., 2014; Marriggio et al., 2021; Dipanwita et al., 2022; Sofronov et al., 2022; Morozova et al., 2024; Sarkar et al., 2024).