Researchers have reported that the teeth of babies with certain genetic variants tend to appear later and that these children have lower numbers of teeth by age one. Additionally, certain of these children whose teeth develop later are more likely to need orthodontic treatment later in life. In a a SNP-based genome-wide association study conducted in approximately 6,000 individuals, the scientists identified five genetic loci (the KCNJ2, EDA, MSRB3, IGF2BP1, and RAD51L1 gene regions) that were significantly associated with both time of first tooth eruption and number of teeth at age one. The researchers also identified five additional loci that were suggestively associated with these same variables. The international team further found that a SNP at one of these suggestive loci (a SNP within the HOXB gene cluster) was associated with a 35 percent increased risk of requiring orthodontia treatment by the age of 31 years. The discovery of genes influencing tooth growth may lead to innovations in the early treatment and prevention of congenital dental and occlusion problems, the authors noted. They also said their findings should provide a strong foundation for the study of the genetic architecture of tooth development, which in addition to its relevance to medicine and dentistry, may have implications in evolutionary biology because teeth represent important markers of evolution. The scientists emphasized that tooth development is not an isolated event. Teeth and several other organs have common growth and developmental pathways in early life. Some of the genes identified here have been linked in previous studies with the development of the skull, jaws, ears, fingers, toes, and heart. The article describing the current research was published online on February 26, 2010, in PLoS Genetics.
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