[7] The neuregulins are a diverse family of proteins formed through alternative splicing from a single gene; they play crucial roles in regulating the growth and differentiation of epithelial, glial and muscle cells.

Hydropathy profile studies have shown that NRG3 lacks a hydrophobic N-terminal signal sequence common in secreted proteins, but contains a region of non-polar or uncharged amino acids in position (W66–V91).

[6] An amino acid region found in SMDF is similar to this non polar site of NRG3 and has been proposed to act as an internal, uncleaved signal sequence that functions as a translocation agent across the endoplasmic reticulum membrane.

[19] Several genes in the NRG-ERBB signaling pathway have been implicated in genetic predisposition to schizophrenia, Neuregulin 3 (NRG3) encodes a protein similar to its paralog NRG1 and both play important roles in the developing nervous system.

[20][21] A recent study of the temporal, diagnostic, and tissue-specific modulation of NRG3 isoform expression in human brain development, employed the use of qRT-PCR ; quantitative polymerase chain reaction to quantify 4 classes of NRG3 in human postmortem dorsolateral prefrontal cortex from 286 normal and affected (bipolar or extreme depressive disorder) candidates with age range of 14 weeks to 85 years old.