MMP9 and schizophrenia: However, this research group discovered that patients who are carriers of the CC genotype in the -1562C/T polymorphism of the MMP gene scored higher on the Positive and Negative Syndrome Scale (PANSS) in SZ than subjects with the CT/TT genotype (p = 0.007), and this may imply a possible relationship between MMP-9-1562C/T SNP and exacerbation of the clinical manifestation of schizophrenia (Ali et al., 2017).