In addition, increasingly refined genetic techniques, such as comparative genomic hybridization microarrays, whole genome linkage, and gene association studies, have allowed researchers to identify numerous chromosomal regions with specific single nucleotide polymorphisms or copy number variants that may be associated with autism. The vast majority of cases of ASD are presumed to be caused by an underlying genetic predisposition and interplay between the genetic code and environmental factors, referred to as the epigenetics of autism. One of the largest, longitudinal, population-based studies to date, involving 1. There are currently multiple studies being conducted evaluating these environmental risks:
Other aspects, such as atypical eating, are also common but are not essential for diagnosis.
Noted autistic Temple Grandin described her inability to understand the social communication of neurotypicalsor people with normal neural developmentas leaving her feeling "like an anthropologist on Mars".
Autistic infants show less attention to social stimuli, smile and look at others less often, and respond less to their own name. Autistic toddlers differ more strikingly from social norms ; for example, they have less eye contact and turn-takingand do not have the ability to use simple movements to express themselves, such as pointing at things.
However, they do form attachments to their primary caregivers. Making and maintaining friendships often proves to be difficult for those with autism. For them, the quality of friendships, not the number of friends, predicts how lonely they feel. Functional friendships, such as those resulting in invitations to parties, may affect the quality of life more deeply.
The limited data suggest that, in children with intellectual disability, autism is associated with aggression, destruction of property, and tantrums. In the second and third years, children with autism have less frequent and less diverse babbling, consonants, words, and word combinations; their gestures are less often integrated with words.
Both autistic groups performed worse than controls at complex language tasks such as figurative language, comprehension and inference. As people are often sized up initially from their basic language skills, these studies suggest that people speaking to autistic individuals are more likely to overestimate what their audience comprehends.
Repetitive movements, such as hand flapping, head rolling, or body rocking. Time-consuming behaviors intended to reduce anxiety that an individual feels compelled to perform repeatedly or according to rigid rules, such as placing objects in a specific order, checking things, or hand washing.
Resistance to change; for example, insisting that the furniture not be moved or refusing to be interrupted. Unvarying pattern of daily activities, such as an unchanging menu or a dressing ritual.
This is closely associated with sameness and an independent validation has suggested combining the two factors. Interests or fixations that are abnormal in theme or intensity of focus, such as preoccupation with a single television program, toy, or game.
Behaviors such as eye-poking, skin-pickinghand-biting and head-banging. Autistic individuals may have symptoms that are independent of the diagnosis, but that can affect the individual or the family.
Selectivity is the most common problem, although eating rituals and food refusal also occur;  this does not appear to result in malnutrition.
Although some children with autism also have gastrointestinal symptomsthere is a lack of published rigorous data to support the theory that children with autism have more or different gastrointestinal symptoms than usual;  studies report conflicting results, and the relationship between gastrointestinal problems and ASD is unclear.
However, they reported lower levels of closeness and intimacy than siblings of children with Down syndrome ; siblings of individuals with ASD have greater risk of negative well-being and poorer sibling relationships as adults.
Typically, autism cannot be traced to a Mendelian single-gene mutation or to a single chromosome abnormalityand none of the genetic syndromes associated with ASDs have been shown to selectively cause ASD.
Some such as the MMR vaccine have been completely disproven. This has led to unsupported theories blaming vaccine "overload"a vaccine preservativeor the MMR vaccine for causing autism. How autism occurs is not well understood. Its mechanism can be divided into two areas: It is not known whether early overgrowth occurs in all children with autism.
It seems to be most prominent in brain areas underlying the development of higher cognitive specialization. An excess of neurons that causes local overconnectivity in key brain regions.
Children with autism have been found by researchers to have inflammation of both the peripheral and central immune systems as indicated by increased levels of pro-inflammatory cytokines and significant activation of microglia.
The MNS operates when an animal performs an action or observes another animal perform the same action. Hypo-connectivity seems to dominate, especially for interhemispheric and cortico-cortical functional connectivity.
The first category focuses on deficits in social cognition. An extension, the extreme male brain theory, hypothesizes that autism is an extreme case of the male brain, defined psychometrically as individuals in whom systemizing is better than empathizing.
In his review, Kenworthy states that "the claim of executive dysfunction as a causal factor in autism is controversial", however, "it is clear that executive dysfunction plays a role in the social and cognitive deficits observed in individuals with autism".
One strength of this theory is predicting special talents and peaks in performance in autistic people. These deficits are present in early childhood, typically before age three, and lead to clinically significant functional impairment.Autism.
Autism (or autistic disorder) is a pervasive developmental disorder which is part of the autism spectrum disorders (ASDs) characterized by severe deficits and pervasive impairment in multiple areas of development including impairment in reciprocal social interaction, impaired communication, and the presence of stereotyped behaviors, interests, and activities (APA, ).
Autism is said to be increasing; however, it is not entirely clear whether the increase is related to changes in how it is diagnosed or whether it is a true increase in the incidence of the disease.
Autism Spectrum Disorders in Early Childhood: An Overview for Practicing Physicians James E. Carr, PhD*, Linda A. LeBlanc, PhD Department of Psychology, Western Michigan University, West Michigan Avenue.
Find out about autism spectrum disorder symptoms, causes, treatment, (ASD) is a neurological and developmental disorder that begins early in childhood and lasts throughout a person's life.
It affects how a person acts and interacts with others, communicates, and learns. Autism (Centers for Disease Control and Prevention).
The Childhood Autism Rating Scale (CARS) is used widely in clinical environments to assess severity of autism based on observation of children. Through this movement, people hope to cause others to think of autism as a difference instead of a disease.
Proponents of this movement wish to seek "acceptance, not cures.". Autism seems to be a disease on the severe end of a spectrum of chronic diseases which includes Asperger’s disease, developmental disorders, Attention deficit (hyperactivity) disorder, childhood asthma, juvenile rheumatoid arthritis, and other auto-immune diseases.
The incidence of these illnesses has also increased dramatically since the.