Autism Spectrum Disorder Definition & Symptoms: Gene Mutations Passed by Mothers to Sons Increases Risk?

A study on autism published in the May 11 issue of Nature Genetics sheds new light on its cause. Researchers discovered that an unusual gene mutation can increase autism risk, according to Science Daily.

The study analyzed data from 2,377 kids and their families. The experts used exome sequencing to produce genetic data. This process particularly centers on protein-coding in the genes, where mutation has been determined as only appearing in the child, but neither parents has it. The mutation is termed as "de novo" to indicate such a case. However, not every case of autism can be attributed to "de novo."

The experts further examined the risk from this mutation and concluded that the mutated gene puts the male offspring at greater risk. The female offspring, however, can inherit the genetic mutation and live with it all their lives without developing autism. According to the Science Daily report, the latest findings offer the "most complete genetic pictures of autism to date."

"The ability to examine these two types of genetic variation in exome sequencing data is the first step toward obtaining a more complete genetic picture at an individual level in the context of autism," said the authors of the study, Niklas Krumm and Tychele Turner, from the University Of Washington Department Of Genome Sciences.

Krumm and Turner also pointed out that understanding how the genes produce these abnormal proteins can help other researchers come up with better autism diagnosis and treatments. "Knowing more about these genes will set the stage for personalized medicine by allowing for targeted treatments specific to an individual. This gives parents more insight and information about their child's condition," remarked Raphael Bernier from the Seattle Children's Autism Center in the Science Daily report.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects a child's way of communicating and interacting with his environment. It is exhibited by a child's restricted and repetitive patterns of behavior and activities. The American Psychiatric Association's Diagnosis and Statistical Manual of Mental Disorders defines the disorder as separate from autism, childhood disintegrative disorder, Asperger's syndrome and other "pervasive developmental disorder" that have not been specified, according to Mayo Clinic.

ASD's symptoms are exhibited early in a child's life, particularly in the first two years.  A child with ASD do not develop the usual patterns, especially with communication and social skills, as a normal child does. Once older, the symptoms may also present themselves in a way that impairs social and occupational functions.