Autism, a serious developmental disorder in children, may arise from a mixture of sources that include a few genes and alterations in the factors that regulate genes (epigenetics) that may be inherited or occur as a new event, said researchers from Baylor College of Medicine.
“This new model represents a new kind of complexity in understanding this puzzling disease,” said Dr. Arthur Beaudet, senior author on the paper and chair of the BCM department of molecular and human genetics. It could also explain the difficulty in identifying genes that cause autism. The report appears online in the American Journal of Medical Genetics.
Autism usually appears by age 3. The result of a neurological disorder, it affects the child’s ability to interact and communicate with other people on both a verbal and non-verbal level.
Beaudet and his colleagues theorize that only a few genes – one of them the cause of Angelman syndrome – are involved. However, the factors acting on these genes are complex, resulting in a puzzle that is difficult to unravel.
There are currently two schools of thought on the cause of autism. One group thinks that 10 or more genes may be involved. Another thinks only a few may cause the disease.
The fact that genes are involved is obvious. Studies of twins showed that identical twins, who share the same DNA, are much more likely to share the diagnosis of autism than fraternal twins, whose DNA is different.
Based on a series of experiments, Beaudet and his colleagues theorize that epigenetic and genetic factors can cause autism by abnormal alterations in the regulation of two or more principal genes. The gene for Angelman syndrome is the strongest candidate known for one of these genes. This defective regulation that may or may not include a mutation in the genes themselves may occur through inheritance or arise newly in the person with the disorder.