Definition :

Autism or autismspectrum disorder (ASD) , Refers to a broad range of conditions characterizedby challenges with social skills, repetitive behaviors, speech and non verbalcommunications.

          Autism is a spectrum disorder, eachperson with autism has a distinct set of strengths and challenges. The ways inwhich people with autism learn, think and problem solve can range from highlyskilled to severely challenged. Some people with ASD may require significantsupport in thin daily lives, while others may need less  support in some cases, live entirelyindependently.

          Children with autism experience theworld differently than the rest of us. Many inhabit a world of their own.Parents complain that the child just doesn't seem to be very interested in playingwith other kids.

Causes :

PrenatalViral infection has been called the principal non genetic cause of autism.Congenital rubella syndrome is the most convincing environmental cause ofautism.

Genetics :

Epigeneticmechanisms may increase the risk of autism. Epigenetic changes occur as aresult not of DNA sequence changes but of chromosomal histone modification ormodification of the DNA bases. Such modifications are known to be affected byenvironmental factors, including drugs and Mental stress.

Prenatalenvironment : The risk of autism is associated with several prenatal riskfactors, including advanced age of either parent, Diabetes, Bleeding & useof psychiatric drugs in the mother during pregnancy . Prenatal viral infectionhas been called the principal non- genetic cause of autism.  Teratogens are environmental agents thatcauses birth defects.

Mentalinflammatory and autoimmune disease can damage embryonic and fetal tissue,aggravating a genetic problem or damaging the nervous system.

Perinatal & obstetric conditions :

Low birthweight and gestation duration, Hypoxia during child birth.

Pathophysiology :

Severalgenes have been implicated in the pathogenesis of ASD, most of them areinvolved in neuronal synaptogenesis . A number of environmental factors andassociated conditions such as gastrointestinal abnormalities and immuneimbalance have been linked t hw pathophysiology of ASD.