Causes of Autism Remain Mysteriousby Richard Kensinger, MSW | February 2, 2015
This pervasive developmental disorder appears to be increasing in incidence and prevalence. Current estimates are that 1 in 88 people have autism, with males four times more likely to develop it. But are we any closer to figuring out what causes it?
What some professionals describe as “classical” autism consists of poor communication, lack of eye contact, lack of imagination, a requirement for excessively rigid daily routines, and an inability to decipher non-verbal signals. The latter is sometimes referred to as being “double mind-blinded”, meaning that people with autism are unable to develop a sense of their own mind and understand the minds of others.
We also believe that people with autism process senses across the sense modalities differently to those without autism. Some think the disorder can be detected at around 18 months, while some say detection is possible even earlier. To the best of my knowledge, autism cannot be detected in-utero. And we presume that the genetic contribution to this disorder is substantial.
Recent clinical findings have been outlined in a New York Times article written by Benedict Cary. He reports on an investigation of whole genome sequencing on 85 families that all have two siblings with this disorder. The study was funded by Autism Speaks – a prominent advocacy group – and carried out at the University of Toronto, Canada.
The conclusions based on the data reveal several points. Firstly, 100 genetic “glitches” have been identified. Siblings in the same family are far more different than similar in regards to their clinical presentation. About one-third of siblings who show some of the same mutations are in fact similar in its expression. The majority do not. This indicates that the genetic contribution is more polygenic than realized, and this disorder is indeed not homogenous. These researchers, and others who review their findings, observe that “genetic mapping for this disorder is weak”.
Given the poor to guarded prognosis for most of those with autism, these findings thus far are not very promising in regards to clinical interventions. The search for clues continues, as it must. Another group of investigators has compiled a registry of about 2800 families who contain at least one offspring with autism. Perhaps then, additional clues will surface.
Cary, B (26 January, 2015). More Differences Than Similarities Are Found in Autistic Siblings, New York Times. Accessed 29 January 2015.
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