**2.5 TGF-β**

It is a multifunctional cytokine that plays an important role in cellular differentiation, apoptosis and angiogenesis. It exists in three isoforms TGF-β1, β2, and β3. Cui et al. in their meta-analysis found significant association between TGF-β SNP and periodontitis in Asian population. However, few other studies by different authors did not show any association.
