Functional polymorphism of matrix metalloproteinase-9 (MMP-9) gene and response to lithium prophylaxis in bipolar patients

Abstract

Matrix metalloproteinase 9 (MMP-9) has been implicated in a number of pathological conditions including cancer and heart diseases, and recently also in such neuropsychiatric disorders as schizophrenia and bipolar illness. Therefore, we investigated a possible association between functional polymorphisms of the MMP-9 gene and the response to lithium, the main mood-stabilizing drug in bipolar illness. One hundred and nine bipolar patients treated with lithium for at least 5 years were analyzed. The lithium response was assessed as--excellent: no affective episodes during lithium treatment; partial: 50% or more reduction in the episode index; no response: less than 50% reduction, no change or worsening in the episode index. The -1562C/T MMP-9 gene polymorphism (rs3918242) was assessed by PCR-RFLP method. Genotype distributions were not in Hardy-Weinberg equilibrium. No association was found between polymorphism studied and the quality of response to prophylactic lithium administration. The functional polymorphism of the MMP-9 gene, analyzed in this study, may not be associated with the treatment response to lithium in bipolar patients.