Autistic disorder is a neurobiological developmental disorder that is usually reliably diagnosed by the age of three and the first diagnosis can be made at 18 months of age. It is characterized by significant retardation and dysfunction in speech and communication, the development of cognitive skills and social behavior.
Autistic disorder usually lasts a lifetime. The severity of the disorder can range from moderate to very severe. In the latter case, people with autism may not be able to meet basic human needs.
The heredity of autistic disorders is high as shown by studies with monozygotic twins where the chances of being diagnosed with both siblings with autistic disorder are high (60-95%), while in dizygotic twins the chances of being diagnosed with a second sibling with autism are high. much lower (5-10%), but nevertheless higher than the chances of developing the disorder in siblings of the general population (Bailey, Luther, Bolton, LeCourteur, & Rutter, 1995). It is important to note that while most siblings of children with autism develop normally, 5-10% of children have a variety of cognitive impairments such as difficulty reading and speaking.
Factors that contribute to the occurrence of autism spectrum disorders include the following: chromosomal abnormalities (fragile X syndrome), metabolic disorders (phenylketonuria), pre- and perinatal causes (congenital erythema, congenital or neoplastic hemorrhage, end of pregnancy), as well as medicines or drugs taken during pregnancy. Also, the comorbidity of autism and epilepsy (approximately 35-45% of children with autism have pre-adolescent seizures and peak in adolescence) suggests that epilepsy or the causes leading to epilepsy may also contribute to autism.