Pervasive Developmental Disorders

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Introduction

The Case of...

a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.

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Causes and Risk Factors

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Pathophysiology

Autism

Genetic and Chromosomal Abnormalities

18% of people with fragile X have autism, while 5% of people with autism have fragile X. Other chromosomal abnormalities are seen in 5% of people with autism.

The 5-HT transporter or receptor gene appears affected in some people.

Metabolism

PKU, histidinemia, Lesch Nyhan Syndrome

Infections

rubella, CMV, herpes simplex, HIV

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Autism Spectrum Disorder

There is a triad of symptoms in autism.

social interaction impairments

marked impairment in multiple nonverbal behaviour
failure to develop peer relationships
markedly impaired expression of pleasure in other people's happiness
lack of social or emotional reciprocity

communication interaction impairments

delay in/lack of spoken language, not compensated for by mime, gestures, etc; highly variable
if adequate speech, marked impairment to iniate or sustain conversation
stereotyped, repetitive use of language
lack of spontaneous make-belief play or social imitative play

repetitive, restrictive, or stereotyped behaviours

encompassing preoccupation with special interests abnormal in intensity or focus
compulsive adherence to non-functional routines or rituals
stereotyped motor mannerisms
persistent preocupation with parts of objects

decision-making