Autism Linked To Specific Chromosome

In what could be a significant step in the path to treating autism, scientists said Thursday that they have narrowed the brain disorder to a certain group of missing DNA segments in a particular chromosome.

Drs. M. Anne Spence and Moyra Smith, professors of pediatric genetics, led a team that studied an autistic 7-year-old boy and found that about 1,000 building blocks of DNA were missing from the 15th chromosome.

"We found that a number of genes normally on the chromosome were deleted at the point of breakage in the deleted chromosome in our patient," Spence told reporters. "This detailed information can help us try to match these deleted genes with suspected genes for autism and piece together how genes interact with the body to result in autism.

"We think this information will then help us uncover links that, once understood, could eventually result in a treatment for the disorder," Spence said.

Autism, a severe brain disorder that has no known cause, usually appears in early childhood and affects as many as one in 500 Americans.

Those with the disease have impaired thinking processes, emotions and social abilities, causing them to become isolated, Andrew Porterfield of UCI's College of Medicine said.

They are often socially withdrawn and have an inability to communicate.

A genetic link has long been suspected in autism, but finding the specific genes that make people susceptible to the disease has been difficult.

"It is most likely brought about by the interaction of multiple genes, each contributing a small part in causing the disease," Spence said. "We are grateful to this patient's family and to other participants for allowing us to continue the research that we hope will put this complex genetic puzzle together and give us insight on the causes and treatment for autism."

The research, sponsored by the National Institutes of Health and other organizations, is part of a nationwide study of autism.

The researchers are looking at other patients with autism and using brain-scanning technology to look for developmental and physiological changes in the brain that may occur with autism, Porterfield said.

The study, titled "Neuropsychiatric Genetics," appears in the Dec. 4 edition of the American Journal of Medical Genetics.

The research also was supported by grants from the National Institute of Child Health and Human Development and the National Alliance for Autism Research, Porterfield said.

More Information:

• National Institutes of Health's Autism Site
• Teratology Society -- scientific society that studies the causes and biological processes leading to abnormal development and birth defects
• Complete definition of autism by the National Alliance For Autism Research