Human papillomavirus 13 L1 gene polimorphism: first report

Introduction. Human papillomavirus 13 (HPV-13) belonging to Alphapapillomavirus-10 species, is an oral mucosotropic virus phylogenetically related to others human papillomavirus (6, 11, 44, 55 and 74). It causes Multifocal Epithelial Hyperplasia, an uncommon benign oral disease reported mainly amongst ethnic groups from America. Objective. To describe the genetic variability of the HPV-13 L1 gene. Material and Methods. A retrospective study including 50 oral samples from patients with Multifocal Epithelial Hyperplasia, and 25 samples from asymptomatic carriers of HPV-13, all subjects living in Mayan area of Mexico. A fragment 240 bp corresponding to the HPV 13L1 gene, which encodes the major capsid protein was amplified, sequenced, and compared with the only two reference sequence of HPV-13 available. A phylogenetic tree was constructed using PAUP* software. Results. Eight single nucleotide polymorphisms were identified including three synonymous polymorphism and five non-synonymous. According to the phylogenetic tree, the variants were grouped in two branches. Conclusion: This is the first study of the genetic variability of HPV-13. A dominant polymorphism shared by patients and asymptomatic carriers was identified.