Pertinent data for the practicing Pediatrician on Autism Spectrum Disorder.  

In an outstanding, comprehensive and simple way, this article from the American Academy of Child and Adolescent Psychiatry gives the most up-to-date outline on ASD.

The following few items culled from the article may be of special interest to the practicing pediatrician:

a.   Various theories exist regarding etiology.

b.   Post-mortem studies show abnormalities within the limbic   system.

c.   Functional MRI has identified difficulties in tasks involving social, affective judgment and the processing of facial and non-facial stimuli.

d.   Structural MRI suggests a brain size increase.

e.   Diffusion Tensor Imaging indicates aberrations in white matter tract development.

f.   Neurochemical studies find high blood levels of serotonin, and a role for dopamine hasn't been excluded.

g.   For vaccines (in particular MMR) and thiomerosol, the preponderance of evidence does not support either as an etiological factor.

h.   A role for the immune system has not been excluded.

i.   There is a high risk for ASD in siblings and an even higher one for identical twins, providing strong support for a genetic (multiple) involvement.

j.   Identified risk factors include: Closer spacing of pregnancies, advanced maternal or paternal age and extremely premature birth (<26 weeks).

k.   Comorbidities include intellectual disability (only 25% are in normal range), behavioral difficulties and "affect" symptomatology, plus others.

Journal of the American Academy of Child and Adolescent Psychiatry