**3.7 Evidence for the role of genetic variants in periodontitis**

The above mentioned studies demonstrate that different genetic loci are capable of causing the disease in dominant and recessive ways [32]. Few of the genes responsible are autosomal whereas others are X-linked. These factors account for the different observed modes of transmission (**Tables 1**–**4**).


#### **Table 1.**

*Segregation analysis.*


**Table 2.** *Twin studies.* *Genetics and Periodontal Disease: An Explicit Insight DOI: http://dx.doi.org/10.5772/intechopen.99266*


#### **Table 3.**

*Linkage studies.*


**Table 4.** *Association studies.*
