[Early diagnosis of autism: Phenotype-endophenotype]

Autism Spectrum Disorders have for some time been the focus of intense interest for clinicians and researchers because of the high prevalence of the disorders among children in the community (approximately 1%), their severity and pervasiveness. Particular attention has been paid to the early diagnosis of the disorder and to the intensive therapeutic intervention. Currently the best prognosis for autism lays in the early diagnosis and intervention. Postponing the diagnosis and the intervention beyond infancy is considered loss of precious time. The diagnosis of autism, which begins early in life, was until recently considered that could be reliability made at the age of 3 years. Recent follow up studies however on children at risk for autism (children who had an older sibling with autism) have shown that the clinical signs of autism emerge at the end of the first year and become distinct by the end of the second year when the diagnosis can reliably be made. From a clinical perspective it is noted that the early clinical signs of risk for autism are related to social communication (e.g. limited or absent response when calling his/her name and to joint attention), stereotype behaviours and body movements or unusual handling of objects (e.g. intensive observation of objects and stereotype movements of hands and tapping or spinning), incongruent regulation of emotions (reduced positive and increased negative emotion). There is also delay in developmental characteristics such as the language (both receptive and expressive) and motor (particularly in postural control - characteristic is the drop of the head backwards when the infant is held in horizontal position). Studies on various aspects of the endophenotype of certain clinical signs among infants at risk for Autism Spectrum Disorders, such as avoidance of eye contact, delay in verbal communication and increase of the head circumference, may provide useful information and may assist the clinician on follow up in the early diagnosis. Compared to the progress made for an early diagnosis of autism there is relatively no equal progress in the early intervention. However, some methods such as the 'Early Start Denver Model' which focuses in the family, which is the natural environment of the child, may provide a useful framework for effective work with the child and the family.