Autistic%20disorder Signs and Symptoms

Autism is a neurodevelopmental disorder that begins in childhood that involves:

• Impaired social interaction
• Impaired communication
• Lack of developmentally appropriate behavior, interests or activities
• Presence of restricted and repetitive patterns of behaviors, interests or activities

Deficit in Social Skills

• Abnormal eye contact
• Failure to orient to name
• Failure to use gestures to point or show
• Lack of interactive play
• Failure to make appropriate social smile
• Lack of sharing of emotion or interest
• Lack of interest in other children
• Often withdrawn and spends hours in solitary play with restrictive or repetitive interests and behaviors

Impaired Social Interaction

• Impairment in joint attention - ability to use eye contact and pointing for the purpose of sharing experiences with others
• Deficits in empathy for what another person might be feeling
• Deficits in understanding what another person might be thinking

Deficit in Language and Communication

• Nonverbal that ranges from minimal vocalization to having some speech (eg capable of imitating songs, rhymes, or television commercials)
• Odd prosody or intonation of speech
• Echolalia
• Pronoun reversal
• Nonsense rhyming
• Other idiosyncratic language forms

Aberrant Play Skills

• Little symbolic play
• Ritualistic and rigid behavior, needs to maintain a consistent, predictable environment
• Tantrum-like rages when routines are disturbed
• Preoccupation with parts of objects

Restricted, Repetitive Behaviors, Interests or Activities

• Stereotyped or repetitive motor movements (eg lining up objects, flipping objects)
• Insistence on sameness, inflexible adherence to routines or other rituals
• Highly restricted, fixated interests

Variations in Intellectual Functioning

• Mental retardation to superior intellectual functioning in select areas (splinter skills, savant behavior)
• Typical development in certain skills and can even show strength in specific areas, such as puzzles, art, or music

Heightened Awareness to Stimuli

• Visual scanning of hand and finger movements
• Mouthing of objects
• Rubbing of surfaces

Lowered Sensitivity to Stimuli

• Diminished response to pain
• Lack of startle response to sudden loud noises

Epidemiology

• Prevalence rate of ≥1% in children and young individuals
• More frequent in boys
• Estimated prevalence rate in siblings of a child with autism spectrum disorder is 10%
• ≥1% of children have regression or stasis of language and social behavior, usually occurring between ages 1 and 2 years

Pathogenesis
Genetic Factors

• Brain development alteration specifically neural connectivity which affects social communication development and resulting to restricted interests and repetitive behaviors
  • It has been proposed that interactions between multiple genes or gene combinations are responsible for autism spectrum disorders (ASD) and that exposure to environmental modifiers help contribute to variable gene expression

Neurobiologic Factors

• Atypical neural connectivity as a result of abnormal neuronal differentiation during prenatal development contribute to the development of ASD

Parenteral Age

• Advanced paternal or maternal age have been postulated to cause de novo spontaneous mutations and/or genetic imprinting alterations leading to development of ASD

Environmental and Perinatal Factors

• Eg exposure to toxins or teratogens, perinatal insults, prenatal infections (eg rubella, cytomegalovirus)
• Effect depends on timing and duration of exposure, toxin concentration, mechanism of action and distribution in the central nervous system
• Modulate existing genetic factors predisposing to autism spectrum disorder

• Risk factors include advanced parental age, prematurity, neonatal encephalopathy and genetic vulnerability