A risk factor is something that increases your likelihood of getting a disease or condition.

It is possible to develop ]]>autism]]> with or without the risk factors listed below. However, the more risk factors you have, the greater your likelihood of developing autism. There is no way known to modify your child's risk for autism.

Genetic Factors

Genetics is believed to play a role in the risk of autism because the condition is:

  • More common in families
  • More common in identical twins
  • May be more common in parents with psychiatric illness
  • More common in families who have other family members with other forms of communication or social disorders.


Caucasian males are more likely to be affected by autism than females. When girls are affected, though, they may have more profound symptoms.

Age of Parents

Older parents (eg, mother's age over 35) may have a higher risk of having a child with autism.

Medical Conditions

Autism occurs more frequently in children with rare genetic disorders or other medical conditions, including:

  • Tuberous sclerosis—A rare, multi-system genetic disease that causes benign tumors to grow in the brain and on other vital organs such as the kidneys, heart, eyes, and skin. It commonly affects the central nervous system and results in a combination of symptoms including ]]>seizures]]> , developmental delay, behavioral problems, skin abnormalities, and ]]>kidney disease]]> .
  • ]]>Fragile X syndrome]]> —A hereditary disorder of the X chromosome. It is the most common cause of inherited mental retardation.
  • ]]>Neurofibromatosis]]> —A genetic disorder of the nervous system. It causes tumors to grow on the nerves in any part of the body. Neurofibromatosis can also produce other abnormalities, such as changes in the skin and deformed bones.
  • ]]>Phenylketonuria (PKU)]]> —A genetic disorder of the enzyme that breaks down phenylalanine, which is an amino acid found in certain foods. Without a proper diet, PKU can lead to ]]>intellectual disability]]> .
  • Problems during pregnancy or delivery, including ]]>rubella]]> —Rubella is a mild, highly contagious illness that is caused by a virus. It is characterized by a rash, swollen glands, and joint pain. If a pregnant woman has rubella, it can cause birth defects in her baby. Other possible risk factors include breech delivery and birth at less than 35 weeks gestation.
  • ]]>Epilepsy]]>—The term “epilepsy” refers to any disorder characterized by recurrent seizures. During a seizure, you may lose consciousness, stare into space, have convulsions (abnormal jerking of the muscles), or experience abnormalities of sensation or emotion.
  • Tourette’s syndrome
  • Newborn encephalopathy—This is a syndrome of disturbed brain function that includes breathing difficulties, problems with reflexes, seizures, and other symptoms.
  • Moebius syndrome, ]]>cytomegalovirus]]> , herpes encephalitis—These are sometimes listed as associated conditions.