Meng-Chuan Lai, et.al., Autism, The Lancet 2014, volume 383, issue 9920, doi:10.1016/S0140-6736(13)61539-1
Genetics has a key role in the etiology of autism, in conjunction with developmentally early environmental factors. Large-effecct rare mutations and small-effect common variants contribute to risk.
In ICD-10, autism was referred to as pervasive developmental disorder, emphasized the early onset of a triad of features: impairments in social interaction; impairments in communication; and restricted, repetitive, and stereotyped behavior, interests, and activities.
Nowadays, the median worldwide prevalence of autism is 0.62-0.70%.
Large-scale population-based studies have shown that 2-3 times more males are affected.
Understanding of gene-envioronment interplay in autism is still at an early stage.
Could be related to germ line mutation, particularly when paternal in origin. Alternatively, individuals who have children late in life might do so because they have the broader autism phenotype.
Prevalence of autism have been reported to be two times higher in cities where many jobs are in the information-technology sector than elsewhere.
Individuals with autism have a mortality risk that is 2.8 times higher.
Signs of autism are not reliably present at birth, but emerge through a process of diminishing, delayed, or atypical development of social-communication behaviors, starting between the age of 6 and 12 months.
Autism is characterized by atypical neural connectivity, rather than by a discrete set of atypical brain connectivity.
One frequently reported neuroanatomical feature of autism is a trajectory of generalized early brain over-growth when aged 6-24 months.
Neuroimmune mechanisms could have key roles in some aspects of the pathophysiology of autism, but the exact biology awaits clarification.
Twin studies have suggested that autism have high heritability (more than 80%).
The genetic architecture of autism have proved to be complex and heterogeneous.
Some of these rare mutations are clinically identifiable; therefore, screening is recommended as part of routine clinical examination.
Although autism is rooted in biology, most effective interventions so far are behavioral and educational; drugs have had only a minor role so far.
No biomedical agent has been shown to reliably improve social communication; experimental trials of drugs targeting various systems are in progress.