MMP9 and Guillain-Barre syndrome: Furthermore, it was demonstrated that the polymorphic variant of the SNP allele in the MMP-9-1562C/T gene was more frequent in patients with severe GBS, when compared to patients with mild GBS (13.6 vs. 5.7%, OR = 2.6, 95% CI = 1.1–6.0, p = 0.02) (Geleijns et al., 2007).