MMP3 and arteriovenous malformations of the brain: Further, we detected differential transcriptional activity of the MMP3 promoter caused by −709 polymorphism, finding that the minor allele G induced a lower transcriptional activity and lead to a decreased expression of MMP3 than did the major allele A. This result is consistent with our previous finding in an epidemiology case-control study that variant allele −709G was significantly associated with a decreased risk of developing BAVM [19].