More orthodontics visits for kids whose first teeth are slow to erupt?
Writing in the open-access journal Public Library of Science (PLoS) Genetics, British and Finnish geneticists pinpointed five genes linked with the time the first milk tooth emerges from a baby's gums. Although this tooth is temporary, the scientists hypothesised that it is an extremely important part of the baby's overall health and well-being. Their hunch turned out to be correct. The study's findings are part of the EURO-BLCS ('Biological, clinical and genetic markers of future risk of cardiovascular disease'), which received EUR 1.4 million under the 'Life quality' Thematic area of the EU's Fifth Framework Programme (FP5). The move towards a mouth full of gleaming teeth is a rite of passage that can take a little one the first three years of life to complete. It starts in the womb, with the development of tooth buds, the foundation for the first teeth. Parents will often see that first tooth - a tangible sign that their baby is growing up - at around six months, which is usually the time their baby's diet begins to include solid foods. An early developer may see his or her first white cap as early as three months, while a late bloomer may have to wait until the age of almost one. Do teeth first appear as unexpected as the baby takes the first few unsteady steps? Determined to confirm the paramount importance of the prenatal environment in tooth growth, the researchers set their sights on the critical role gene expression plays. The team scanned the entire genetic code of 6,000 individuals from Finland and the UK who participated in the Northern Finland Birth Cohort and the Avon Longitudinal Study on Parents and Children. By closely following participants from the mother's early pregnancy until adulthood, these studies offered Professor Marjo-Riitta Jarvelin of the School of Public Health at Imperial College London in the UK and her colleagues a real-life glimpse on how teeth are originally designed. Their findings laid out a list of five gene variants that seemed to control when a baby will push his or her first teeth through the gum line. The first teeth to appear are usually the two bottom front teeth, also known as the central incisors. Teeth will then sprout one after another, the top two middle ones will follow, and finally the ones along the sides and back. Interestingly, the same five gene variants, once intertwined, also hold the key to later tooth development. Professor Jarvelin's research team questioned whether the tooth number at age one is similarly controlled by gene variants. As straightforward as the question seemed, the answer is not a simple one. Teeth usually do not become visible until after birth. Their formation, however, starts in early development. As the baby's face takes shape in the womb, the development of teeth and palate are tightly controlled in space and time by gene expression. Related abnormalities could result in the development of teeth outside of the normal row, and missing teeth, and the new insights may suggest ways to combat these malformations. The scientists described in their paper how the concerted actions of hundreds of genes are needed to build a tooth, but the first tooth of babies carrying these five gene variants tends to appear later. In addition, these late bloomers are more likely to have fewer teeth by the age of one and may need orthodontic treatment. The implications of these surprising findings go beyond tooth development, the geneticists revealed. What was surprising is that this list includes genes known to be involved in the development of several other parts of the body like the skull, fingers and toes, but also of the heart. Although, it's not unusual for a gene to have multiple functions, the scientists are hopeful that once their findings are confirmed, their research could lead to the establishment of genetic variants that raise the risk of cancer and other aggressive diseases later in life. 'We hope... these discoveries will increase knowledge about why foetal growth seems to be such an important factor in the development of many chronic diseases,' Professor Jarvelin concluded.
Countries
Finland, United Kingdom