A study of susceptibility genes in rare monozygotic twins with generalized aggressive periodontitis

Exploring the effects of susceptibility genes on aggressive periodontitis during its occurrence and development lays a foundation for further research on its genetic pathogenesis.

Medical history and clinical indicators were collected from monozygotic twins with generalized aggressive periodontitis. Susceptibility genes were detected by polymerase chain reaction-restriction fragment length polymorphisms, and the exon gene components were analyzed by whole-exome sequencing.

The severity of generalized aggressive periodontitis in the twins was different (P < 0.05). Florida diagnosis results showed that the younger sister’s explored clinical depth (probing depth, PD) and clinical attachment loss (CAL) were higher than those for the elder sister, but her clinical bleeding index (bleeding on probing, BOP) was lower than that of the elder sister. In addition, their responses to periodontal basic treatment were different (P < 0.05). After treatment, the improvement of CAL and decline in BOP were more obvious in the elder sister, and the proportion of different periodontal pocket depths in the elder sister decreased after treatment, while the decrease was slighter in the younger sister. Genetic tests revealed that the twins had the same genotypes at target susceptibility genes (IL-1β-511, IL-1β+3953, TNF-α-308, FcγR-IIIb, VDR, and ER) and differential exon gene components, and that the suspected differential genes, e.g. ZFPM1, PTH2, ZFYVE16, and LY6G6C, might be related to their phenotypic differences.

These monozygotic twins had different phenotypes of generalized aggressive periodontitis. Their shared susceptibility genes increased the risk of disease, and their different genetic mutations affected the phenotype of the disease.