Risk Factors and Characteristics @ Centers for Disease Control and Prevention
Risk Factors and Characteristics
- Studies have shown that among identical twins, if one child has an ASD, then the other will be affected about 60-96% of the time. In non-identical twins, if one child has an ASD, then the other is affected about 0-24% of the time. [1]
- Parents who have a child with an ASD have a 2%–8% chance of having a second child who is also affected. [1]
- It is estimated that about 10% of children with an ASD have an identifiable genetic, neurologic or metabolic disorder, such as fragile X or Down syndrome. As we learn more about genetics, the number of children with an ASD and an identifiable genetic condition will likely increase. [Read summary
] [Read summary] - A report published by CDC in 2009, shows that 30-51% (41% on average) of the children who had an ASD also had an Intellectual Disability (intelligence quotient <=70). [Read article]
- Studies show that 5% of people with an ASD are affected by fragile X and 10% to 15% of those with fragile X show autistic traits. [Read summary]
- One to four percent of people with ASD also have tuberous sclerosis. [Read summary]
- About 40% of children with an ASD do not talk at all. Another 25%–30% of children with autism have some words at 12 to 18 months of age and then lose them. Others may speak, but not until later in childhood. [2]
