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.

Age

By definition, autism first occurs before the age of three.

Gender

Boys are three to four times more likely to be affected by autism than girls. When girls are affected, though, they tend to have more profound symptoms.

Medical Conditions

Autism occurs more frequently in children with some 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 mental retardation.

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.

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. Epilepsy is a term used to describe a condition in which you have recurrent seizures.

Moebius Syndrome, Cytomegalovirus, Herpes Encephalitis – These are sometimes listed as associated conditions.

Genetic Factors

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

  • More common in families
  • Much more common in identical twins