Asperger Syndrome, Susceptibility To, 1

Description

Asperger syndrome is considered to be a form of childhood autism (see, e.g., 209850). The DSM-IV (American Psychiatric Association, 1994) specifies several diagnostic criteria for Asperger syndrome, which has many of the same features as autism. In general, patients with Asperger syndrome and autism exhibit qualitative impairment in social interaction, as manifest by impairment in the use of nonverbal behaviors such as eye-to-eye gaze, facial expression, body postures, and gestures, failure to develop appropriate peer relationships, and lack of social sharing or reciprocity. Patients also exhibit restricted, repetitive and stereotyped patterns of behavior, interests, and activities, including abnormal preoccupation with certain activities and inflexible adherence to routines or rituals. Asperger syndrome is primarily distinguished from autism by the higher cognitive abilities and a more normal and timely development of language and communicative phrases. Gillberg et al. (2001) described the development of the Asperger syndrome (and high-functioning autism) Diagnostic Interview (ASDI), which they claimed has a strong validity in the diagnosis of the disorder.

Genetic Heterogeneity of Susceptibility to Asperger Syndrome

ASPG1 maps to chromosome 3q. Other autosomal loci include ASPG2 (608631) on chromosome 17p, ASPG3 (608781) on 1q21-q22, and ASPG4 (609954) on 3p24-p21.

Two X-linked forms, ASPGX1 (300494) and ASPGX2 (300497), are associated with mutation in the NLGN3 gene (300336) and the NLGN4 gene (300427), respectively.

Clinical Features

Asperger (1944) described a syndrome, which he termed 'autistic psychopathy,' in which persons of apparently normal intelligence exhibited an impairment in social interaction and behavioral abnormalities without delays in language development.

Mapping

Auranen et al. (2002) found that in their collection of 38 Finnish families in which a proband had autism, approximately one-third of the probands had a first-degree relative with Asperger syndrome or developmental dysphagia. The authors defined this group as having 'autism spectrum disorders.' In 18 families with both autism and Asperger syndrome, the most significant evidence for linkage was found on chromosome 3q25-q27, with a maximum 2-point lod score of 4.31 at theta = 0.0 with D3S3037.

Population Genetics

Bertrand et al. (2001) performed a prevalence study of autism spectrum disorders in Brick Township, New Jersey. There were 6.7 cases per 1,000 children, aged 3 to 10 years, in 1998. The prevalence for children whose condition met full diagnostic criteria for autistic disorder was 4.0 cases per 1,000 children, and the prevalence for pervasive developmental disorder (PDD)-not otherwise specified (NOS) and Asperger syndrome was 2.7 cases per 1,000 children.