Results: In total, 46.6% (n = 7) of the cases in group III aggressive periodontitis (n = 15) and 6.66% (n = 1) in group II stage II periodontitis (n = 15) showed the presence of T. forsythia, and among them, 57.14% (n = 4) showed the presence of the glyA gene. The gene discussed is SHMT2; the disease is periodontitis.