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Autism Spectrum Disorder and Asperger’s Disorder

Autism Spectrum Disorder and related disorders have long been a problem for children and their families. Part of this information is presented with the permission of Sara Kennedy, Ana Krishnan, Simret Nanda, Katharine E. Yoder. Chad Cox, and Philip Omotosho of The Penn State College of Medicine. The information presented at this site is for general use only and is not intended to provide personal advice or substitute for the advice of a qualified professional. If you have questions about the information presented here, please consult a physician, the resources listed or other professional in your area.

Autism and Genetics

Exploring Autism: the Search for a Genetic Etiology Katharine E. Yoder Penn State College of Medicine 2004   Introduction  Autistic Disorder is described in the DSM IV as having the characteristics of: Qualitative impairment in social interaction, Qualitative impairments in communication, Restricted repetitive and stereotyped patterns of behavior, interests, and activities, And delays or abnormal functioning in at least one of the following areas, with onset prior to age 3 years: Social interaction Language used in social communication, or Symbolic or imaginative play, And the disturbance is not described by Rett’s Disorder or Childhood Disintegrative Disorder.   Incidence à possibility of a genetic link General population: 0.04% to 0.1%, Males 3-4x > Females Twin studies: Monozygotic (MZ) and Dizygotic (DZ) –     Autism in concordance rates occurs MZ 300x> DZ –     Autism penetrance not 100% (36.3-95.7%) in MZs –     Strong arguments for genetic as well as non-genetic influences Family studies –     Risk of autism in sibling of autistic child 3% (general pop 0.1%) –     Cognitive disabilities in parents and siblings of autistic inconclusive –     Bias in studies due to less # of siblings if one autistic child in family   Chromosomal Regions of Interest  15q11-13 inverted duplication Region associated with dyslexia and genes for 3-γ-aminobyturic acid (GABA)-A receptor subunits Prader-Willi/Angelman critical region (PWACR) – two types of duplications –     proximal to PWACR, no clinical significance, familial, normal –     within PWACR, often with DD and autism, familial or de novo maternally-derived often > significance vs. paternally-derived = imprinting?   The X chromosome Fragile X: expansion of CGG repeat sequence of Xq27.3 (FMR1 gene) –     2nd most common cause of mental retardation,...

Autism and Neurology

A Review of Current Thoughts on Localized Structural Lesions in Autistic Disorder Philip Omotosho Penn State College of Medicine 2002   Definition and Epidemiology The DSM-IV diagnosis of autistic disorder requires qualitative impairments in social interaction and in communication, plus restricted repetitive and stereotyped patterns of behavior. Autistic disorder (autism) is rare, occurring in 2-5 children per 10,000 live births. It is more common in males, with a male to female ratio of 3:1. Risk of recurrence in siblings is 3-5 percent, a risk about 75 times greater than that in the general population. Autism is among the group of disorders known as the Pervasive Developmental Disorders. The other disorders in the group include Rett’s disorder, childhood disintegrative disorder, and Asperger’s disorder. Mental retardation is associated with 70 percent of cases and seizures with 33 percent. Autistic features are associated with other neurological diseases such as tuberous sclerosis, neurofibromatosis, fragile X syndrome, and phenylketonuria. These findings have led to the conclusion that there is a genetic predisposition to autism.   Structural Abnormalities in Autistic Disorder Several abnormalities have been described in the last 20 years in the study of Autism, including: Delayed maturation of frontal lobe circuitry (Zilbovicius et al., 1993) Decreased functional connections within the cerebral cortex and between the cortex and subcortical regions (Horwitz et al., 1988) Abnormalities of the dentatothalamocortical pathways (Chugani et al., 1997) These findings point not to a specific location in the brain but suggest that autism is due to connection abnormalities between neural networks that process information. The following studies have found evidence for localized structural abnormalities, which could explain clinically observed...

Asperger’s Disorder Review

This disorder did fall under the category of Pervasive Developmental Disorders in which Autistic Disorder, Rett’s Disorder, Childhood Disintegrative Disorder and PDD NOS also fell under. The classification is now revised.

Asperger’s Disorder

Until the criteria for Autism and Asperger’s Disorder are better delineated, clinicians should focus on the level of language development of children with PDDs in order to best estimate prognosis and treatment.

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