Neuregulin 1

Neuregulin 1 or NRG1 is one of the four proteins of the neuregulin family which act on EGFR family of receptors. Neuregulin 1 is produced in numerous isoforms by alternative splicing, and this allows it to perform a wide variety of functions. Neuregulin 1-ErbB4 interactions are thought to play a role in the pathological mechanism of schizophrenia. The protein also has a putative ability to protect the brain from damage induced by stroke.

By 2004, six major isoforms of neuregulin 1 were known:


 * Type I NRG1; alternative names: Heregulin, NEU differentiation factor (NDF), or acetylcholine receptor inducing activity (ARIA)
 * Type II NRG1; alternative name: Glial Growth Factor-2 (GGF2);
 * Type III NRG1; alternative name: Sensory and motor neuron-derived factor (SMDF);
 * Type IV NRG1;
 * Type V NRG1;
 * Type VI NRG1; Types IV-VI are proteins with 3 novel N-terminal domains identified in 2004.

Link to schizophrenia
A number of studies have provided evidence of NRG1 gene relation to schizophrenia. High-risk deCODE (Icelandic) haplotype was discovered in 2002 on the 5'-end of the gene by Stefansson et al. The SNP8NRG243177 allele from this haplotype was associated in 2006 with a heightened expression of the Type IV NRG1 in the brains of people suffering from schizophrenia.