USP Scientists Identify Autism Neuron in Laboratory

11/12/2014 - 09h14

A milk tooth donated by an eight-year-old autistic boy has permitted scientists to test for the first time the effect of drugs on nervous cells affected by autism.

Using live tissue taken from the sample, Karina Griesi Oliveira, a biologist at the University of São Paulo (USP), identified a genetic mutation in the patient. She was then able to recreate the child's neurons in a laboratory to investigate the problematic cells.

Research began in 2009, when the boy's parents took him to the genetic counselling service at USP's Biosciences Institute for an assessment. The boy had already been diagnosed as autistic, but he had never undergone a genetic assessment to identify the causes.

The institution has collected patients' milk teeth since 2001, with the aim of obtaining DNA samples and live material for the culture of cells. This was an idea of the geneticist Maria Rita Passos-Bueno.

Upon studying the boy's DNA, Oliveira could not connect it to any genetic variety of the psychiatric disorder. The boy had classic autism, which is attributed to a combination of genes, perhaps associated with problems in embryonic development or environmental factors.

However, a genetic mutation in the patient intrigued Passos-Bueno. The boy had deactivated one of his copies of the gene TRPC6, which helps to regulate nervous impulses in some neurons. With Passos-Bueno's guidance, Oliveira spent some time at Yale University investigating further.

With access to a database of genomes of other patients, Oliveira found two other autistic people with TRPC6 mutations. This strengthened her conviction that the gene is linked to autism. However, proving this definitively will require more research.

"The genetics of autism are very complicated," Oliveira says. "There are lots of genes involved, and we still don't know exactly which."

It is unlikely that TRPC6 is capable of causing autism alone, though it may indicate a propensity for the disorder. However, this makes it difficult to study with just DNA readings and psychiatric diagnoses to work with.

Pursuing her research further, Oliveira spent time at another laboratory in the United States, which is coordinated by Alysson Muotri, a native of São Paulo who works at the University of California in San Diego.

Muotri is a specialist in creating neurons from iPS cells. These cells are as versatile as embryonic cells, but they can be created from adult cells, like those from the tooth of the autistic boy.

Using this method, Oliveira recreated the patient's neurons in a petri dish and observed that the TRPC6 mutation prevented cells from attaining the correct shape and connecting with each other.

Her research, which was covered in the journal Molecular Psychiatry, has proven that the action of TRPC6 is a contributing factor for autism and suggests drugs that may be able to correct the problem.

Translated by TOM GATEHOUSE

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