Autism A spectrum of neuropsychiatric disorders characterized by deficits in social interaction and communication, and unusual and repetitive behavior.

Autism is a Pervasive Developmental Disorder (PDD) Who, what, when where why? The human brain-normal and abnormal development Genetics Language and cognition Social implications Interventions and therapies

What is a developmental disorder/disability? Birth defects Developmental Disabilities -Cerebral palsy -Down’s syndrome -Learning disabilities and ADHD -Autism and PDDs -Spina bifida -Heart defects -Cleft palate/club foot -Tay Sachs disease Pervasive developmental disorders a group of disorders that are characterized by : impairments in social interaction, impairment in verbal and nonverbal communication, and a restrictive, stereotypic pattern of behaviours Autism Asperger’sRett’s Syndrome Childhood disintegrative disorder PDD-NOS

Characteristics of Autism (1)

Characteristics of Autism (2)

A little history…

Epidemiology of autism

Neuropathology

Copyright ©2004 Society for Neuroscience Schumann, C. M. et al. J. Neurosci. 2004;24: Figure 1. Orthogonal views for segmenting the amygdala and hippocampus on MRI sections

Copyright ©2004 Society for Neuroscience Schumann, C. M. et al. J. Neurosci. 2004;24: Figure 5. Absolute left (a) and right (b) hippocampal volume (in cubic centimeters) by diagnostic group for subjects years of age (*p

Neuropathology What developmental processes might lead to a larger brain? -Increased neurogenesis -Increased gliogenesis, myelination -Increased synaptogenesis -Disturbed migration -Decreased apoptosis -Decreased dendritic pruning

Cellular pathology

Other brain regions

Neuropathology summary

Neurotransmitters Alterations in many neurotransmitter systems in autism -Glutamate -GABA -Serotonin -Catecholamines (norepinephrine, dopamine) -Neuropeptides

Changes in glutamate and/or GABA could lead to alterations in excitation/inhibition

Serotonin

Serotonin- Developmental changes Cortical decreases of AMT uptake (red areas) I n three autistic children in (1B) the frontal cortex (left hemisphere), (1C) frontal and temporal cortices (left hemisphere), and (1D) frontal, parietal and temporal cortices (right hemisphere) are shown.

Is autism a genetic disorder?

First autism twin study-1977 Folstein and Rutter, Nature Total 25 autistic individuals -4/11 MZ pairs concordant for autism (36%) -0/10 DZ pairs were autistic (0%)

Twin studies - Is autism a spectrum? Do non-autistic MZ twins show other abnormalities?

Further twin studies Steffenburg 1989, Bailey 1995

Conclusions from twin studies

Family studies also suggest genetic link

Family studies-negative results

Looking for autism genes

Chromosomal abnormalities

Genes identified from linkage analysis

Gene summary

Controversies in autism