THE ability to attribute mental states to others ('theory of mind') pervades normal social interaction and is impaired in autistic individuals. In a previous positron emission tomography scan study of normal volunteers, performing a 'theory of mind' task was associated with activity in left medial prefrontal cortex. We used the same paradigm in five patients with Asperger syndrome, a mild variant of autism with normal intellectual functioning. No task-related activity was found in this region, but normal activity was observed in immediately adjacent areas. This result suggests that a highly circumscribed region of left medial prefrontal cortex is a crucial component of the brain system that underlies the normal understanding of other minds.

Swedish patients with the oculo-auriculo-vertebral (OAV) spectrum participated in a prospective multidisciplinary investigation. The aims of the study were to describe their systemic and functional defects, especially autism spectrum disorders, and to search for possible etiologic risk factors. Available medical records were studied and the mothers answered a questionnaire on history of prenatal events. A clinical examination evaluating systemic findings, vision, hearing, speech, oral and swallowing function, and neuropsychiatric function, especially autism, was made. Eighteen patients, (11 males, 7 females) aged 8 months to 17 years with OAV were studied. Most frequent systemic malformations included, ear abnormalities (100%), ocular malformations (72%), vertebral deformities (67%), cerebral anomalies (50%), and congenital heart defects (33%). Functional defects consisted of hearing impairment (83%), visual impairment (28%), both visual and hearing impairment (28%), difficulties in feeding/eating (50%), speech (53%), mental retardation (39%), and severe autistic symptoms (11%). Three children were born following assisted fertilization (two intracytoplasmatic sperm injection, one in vitro fertilization), two mothers reported early bleedings, and six (33%) mothers had smoked during pregnancy.

Our results show that abnormalities of the 15q11-q13 region are a significant cause of ASD, accounting for approximately 1% of cases. Maternal interstitial 15q11-q13 duplications, previously reported to be present in 1% of patients with ASD, were not detected in our sample. Although paternal duplications of chromosome 15 remain phenotypically silent in the majority of patients, they can give rise to developmental delay and ASD in some subjects, suggesting that paternally expressed genes in this region can contribute to ASD, albeit with reduced penetrance compared with maternal duplications. These findings indicate that patients with ASD should be routinely screened for 15q genomic imbalances and methylation abnormalities and that MLPA is a reliable, rapid, and cost-effective method to perform this screening.

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Autism is a complex developmental disorder without an established single etiology but with significant contributions from genetic studies, functional research, and neuropsychiatric and neuroradiologic investigations. The purpose of this paper is to review the findings in five studies involving individuals manifesting the characteristic findings of autism spectrum disorder associated with malformations and dysfunctions known to result from early embryogenic defects. These investigations include two associated with teratogens (thalidomide embryopathy, Mobius sequence with misoprostol) and three (most Mobius sequence cases, CHARGE association, Goldenhar syndrome) with no known etiology. These studies suggest that early embryonic development errors often involving cranial nerve palsies, internal and external ear malformations, ophthalmologic anomalies, and a variety of systemic malformations may be associated with autism spectrum disorders statistically more frequently than expected in a normal population. Although the exact time of developmental insult for each condition cannot be identified, the evidence is that it may occur as early as week 4 to 6+ of embryogenesis.