IFNG and oral lichen planus: The chance of hepatitis C-associated OLP in patients of some geographic regions [1], the role of genetic polymorphism of two cytokines (IFN-γ and TNF-α) in partial determination of the oral versus orocutaneous sites of LP development [1], and a possible association between the class II human leukocyte antigen DQB1*0201 allele and development of a severe variant of vulvovaginal-gingival syndrome [15] are among the proposed genetic factors.