‘Tooth Fairy’ works magic to unearth new autism genes

For some children with autism, the ‘Tooth Fairy’ lives in San Diego and wears a white coat. And the Tooth Fairy may offer an answer to what causes their autism, without painful blood draws or skin biopsies.

Alysson Muotri, associate professor of paediatrics and cellular molecular medicine at the University of California, San Diego, created this inventive project in 2012. He realized that rather than force children to undergo upsetting procedures, parents could simply mail one of their child’s baby teeth, which contain enough genetic information to eliminate the need for an in-person visit.

“We announced the project on social networks like Facebook,” Muorti says. “News spread fast.”

The project has roughly 3,500 registered families and 300 teeth so far, and researchers have found five autism candidate genes from the 20 or so cell lines they have sequenced. Several of those genes have never been implicated in autism before.

“We’re finding lots of new genes and sometimes we have no idea what they do, so the next step is to test whether or not those genes are important,” Muotri says. “This type of study may reveal novel pathways in autism and open up the possibility for personalized treatment.”

Autism’s cause is clear in a subset of cases, but the majority of cases are sporadic, meaning they arise from an unidentified combination of genetic and environmental factors.

“Every sporadic individual will likely carry several mutations that probably contribute to a certain extent to the disease, so it is really hard to model that complex phenotype,” Muotri says.

After receiving a tooth, the researchers extract cells from the dental pulp and sequence the whole genome to search for mutations associated with sporadic autism. They then use these dental cells to create induced pluripotent stem (iPS) cells, which can be coaxed into becoming neurons. Muotri says he and his colleagues are the first to use iPS-cell-derived human neurons to model sporadic autism. Simons Foundation Autism Research Institute