Are your cavities caused by genetics?

Friends accuse me of thinking that everything is genetic. Well, there is some truth to that accusation!  To be honest, though, there are a lot of things that have genetic connections that really surprise me. I had always assumed that my cavities were due to bad dental hygiene and bad dietary choices. That is what the hygienist always said. It turns out, genetics plays a big role in whether or not someone gets cavities. As always, though, genetics combines with lifestyle and habits when it comes to the final outcome.

Dental Caries

I like the term dental caries better than 'cavity' -  sounds fancier and less like a big hole in the tooth. No matter how you refer to it, a cavity consists of a damaged area of the tooth enamel that turns into a hole full of decay. Everyone knows that sugar causes cavities. The party line from dentists is that sugar feeds the bacteria on your teeth which then produce acid that eats away at the enamel. So all you need is some sugar, bacteria, and failure to brush for two minutes, twice a day. But wait... There are a lot of people who eat sugar, don't brush well, and don't have a mouth full of cavities. What is going on? It is estimated by researchers that the 'heritability' or genetic component of dental caries is about 50%.[ref] There are two ways that researchers can dig into how genes impact a disease or trait.
  • They can start with an idea of which gene should be involved and then check to see if genetic variants in the gene change the risk of the disease/trait.
  • Researchers can take the genetic data from a large population and combine it with the data on who has a particular disease/trait to see which genetic variants are related to the disease risk.
This second way - looking at large populates and searching the whole genome - has given us some interesting insights into the formation of dental caries. The genetic variants associated with an increased risk of cavities fall into two categories:
  • genes that affect the oral microbiome
  • genes that affect the formation of the tooth enamel.
Some genetic research points to how the oral microbiome interacts with foods. For example, a research study found that kids who carry a GALK2 variant along with Streptococcus mutans, a bacteria that increase the risk of cavities, are at a much greater risk of cavities. The GALK2 gene codes for an enzyme that phosphorylates galactose at high concentrations. The genetic variant causes low concentrations of GALK2, and thus higher amounts of galactose are available in the mouth for the S. mutans to munch on. Galactose is a simple sugar that is found in higher amounts in dairy products. So perhaps the combo of dairy intake, S. mutans bacteria, and low galactose causes cavities for some of us.

Genetic Variants Linked to Cavities

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