PAX9 Polymorphism in Non-Syndromic Hypodontia in the Malaysian Population.

Non-syndromic hypodontia is the developmental absence of more than one tooth that appears as an independent congenital oral trait. Genetic mutations responsible for tooth agenesis have been identified in paired box 9 (PAX9) and muscle segment homeobox 1 (MSX1), genes encoding transcription factors that play crucial roles during odontogenesis. This study aimed to determine the role of PAX9 and MSX1 in non-syndromic hypodontia. Data collection started from April 2016 to June 2017. Thirty-three non-syndromic hypodontia patients volunteered in this study. Clinical examination and panoramic radiography were performed on a cohort of 31 unrelated Malaysian patients with non-syndromic hypodontia and 50 healthy controls. Unstimulated saliva samples were collected for genetic screening purposes following a series of DNA extraction, amplification via PCR, purification, and sequencing processes. Genetic assessment of PAX9 and MSX1 showed no mutations in all exons. Instead, two single nucleotide polymorphisms, G>C, rs4904210 (Ala240Pro) and C>T, rs12881240 (His239) were identified in exon 3 of PAX9. The SNPs were missense substitutions and synonymous codons (silent substitutions) found in both the case and control groups. However, rs12881240 association between hypodontia phenotype was not established due to unclear evidence of His239 affects the risk of occurrence of non-syndromic hypodontia. In contrast, rs4904210 may contribute to non-syndromic hypodontia due to the significant differences between case and control in the general population. This study suggests that differences in genetic variants may be attributed to ethnic diversity in the population, which causes variations in phenotype patterns and distributions. [ABSTRACT FROM AUTHOR]