down expression of nrg1 types i, ii and iii in iranian schizophrenic patients

schizophrenia (scz) is a complex disorder with no clarified etiology or biological diagnosis.  symptoms of schizophrenia including positive, negative and cognitive deficits.the neurodegenrative and neurodevelopmental hypothesis are main views  about the pathophysiology of schizophrenia. neuregulin 1 is one of four proteins in the neuregulin family that act on the egfr family of receptors. nrg1 gene, locating at 8p21.1-22, is produced in numerous isoforms by alternative splicing, which allows it to perform a wide variety of functions. it is essential for the normal development of the nervous system and the heart.at least six major types of neuregulin 1 exist in humans. type i, ii and iii nrg1 are expressed in excitatory and inhibitory neurons, as well as astrocytes , and some types (i and iv) can be regulated by neuronal activity.  we studied expression of types i, ii, iii of nrg1 gene in 31 scz patients and 30 normal subjects using quantitative real time pcr. also positive and negative symptom scale (panss) and brief psychiatric rating scale (bprs) obtained from patients. the findings showed significant (p<0.05) down regulation of all 3 types of nrg1 genes, in scz. also correlations found between down expression of nrg1types and higher scores of panss and bprs. results confirmed role of nrg1 in schizophrenia. results of expression of nrg1 types in schizophrenia are controversial. there are reports about down expression and over expression of nrg1 types in schizophrenia. it seems that because of important role of nrg1 in neurodevelopment of cns any changes in expression of types of gene could cause functional disabilities in brain and psychiatric disorders like schizophrenia.