Genetics Suggest Autism Isnt Just One DisorderIts Hundreds

Geoffrey Ondrich and Waylon Cude are both 16 years old. Both boys have autism, and both would rather use their computers than do almost anything else in the world.

But thats just about all they have in common.

Waylon is serious and intense, and so is the way he uses his computer: He spends hours immersed in online role-playing games, and he interned last summer at IBM, programming Linux for websites.

On a sunny Friday in October, he leans toward a computer monitor in a testing room at the University of Washington in Seattle, where he is part of a study on the genetics of autism. Waylon focuses diligently on his reaction-time test, frowning to himself when he makes a mistake. Throughout the day, he responds politely to questions, especially factual ones, but doesnt engage in chitchat or commentary. At one point, a clinician who has been testing Waylons motor skills remarks that he is almost as nimble at rearranging tiny plastic pegs with his left hand as he is with his dominant right. Waylon doesnt respond.

By contrast, when Geoffrey completes a task for the same study, he gets a few minutes on his iPad, his passport to fun and pleasure. He watches bits of a movie or scrolls through his collection of music until he finds a particular song with a catchy, disco-y beat, and dances happily in his chair.

When he doesnt have music to dance to, Geoffrey often rocks back and forth in his chair, slapping the top of his left wrist with his right hand. The clinician who is working with him struggles to engage his attention as Geoffrey picks up a plate from a toy tea set and peers at it closely. He bites the plate, then rolls a Matchbox car back and forth over the table in front of him.

Its no surprise that these two boys, at the same age and with the same diagnosis, are so different. Clinicians are fond of saying, If youve seen one kid with autism, youve seen one kid with autism, meaning that its impossible to draw conclusions by looking at just a few people.

This diversity has been a major hurdle for understanding autism and for coming up with treatments that can help a majority of people with the diagnosis. Most studies include individuals who share the same phenotype, or outward characteristics, but whose autism may arise from entirely different origins. Because of this, they often produce muddled results. We recognize autism is a really heterogeneous disorder and were not making a lot of headway when we try to study it as a heterogeneous disorder, says Thomas Frazier, director of the Cleveland Clinic Childrens Center for Autism.

A close look at DNA may provide a way through this muddle.

What weve learned in the last five years about the underlying genetics is that there are hundreds, if not a thousand or more, different genetic subtypes of autism, says geneticist David Ledbetter, chief scientific officer at Geisinger Health System in Danville, Pennsylvania.

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Genetics Suggest Autism Isnt Just One DisorderIts Hundreds