A case-control study of the association between tooth-development gene polymorphisms and non-syndromic hypodontia in the Chinese Han population.

Hypodontia is one of the most common anomalies of human dentition. Recent genetic studies provide information on a number of genes related to both syndromic and non-syndromic forms of hypodontia. Fifty putative single nucleotide polymorphisms (SNPs) in 20 genes that play important roles in tooth development were selected, and a case-control study was conducted in 273 subjects with hypodontia (cases) and 200 subjects without hypodontia (controls). DNA was obtained from samples of whole blood or saliva. Genotyping was performed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). A significant difference was observed, between subjects with non-syndromic hypodontia and controls, in the allele and genotype frequencies of two markers [rs929387 of GLI family zinc finger 3 (GLI3) and rs11001553 of Dickkopf-related protein 1 (DKK1)]. Similar results were observed in a subgroup analysis of test subjects (stratified by gender or missing tooth position). However, this analysis showed no significant difference in the haplotype distribution between the controls and the affected subjects. These data demonstrate an association between some SNPs in tooth development-associated genes and sporadic non-syndromic hypodontia in Chinese Han individuals. This information may provide further understanding of the molecular mechanisms of tooth agenesis. Furthermore, these genes can be regarded as candidates for mutation detection in individuals with tooth agenesis.