Objectives: To investigate behavioural symptom profiles and genetic abnormalities in adults with ASD presenting to a clinical diagnostic service.
Methods: We reviewed genetic investigations completed for patients diagnosed with ASD at the Behavioural Genetics Clinic, a specialist clinic providing assessment of autism spectrum disorder at the Maudsley Hospital, London. Diagnostic assessment includes a detailed neuropsychiatric assessment, Autism Diagnostic Interview-Revised (ADI-R) or Autism Diagnostic Observation Schedule (ADOS) pending consent to contact parents/parental availability, physical examination, and genetic investigation. Genetic investigation of blood samples includes a comparative genomic hybridization (CGH) analysis using oligonucleotide arrays with ~44,000 probes across the genome. In addition, a karyotpe analysis and a microarray analysis is conducted. (CGH), also referred to as chromosomal microarray analysis (CMA), and array CGH (aCGH), may identify small deletions and duplications of subtelomers, pericentromeric regions and other chromosome regions, that would not be detected by traditional chromosomal analysis. We reviewed results of diagnostic assessment and CGH genetic investigations completed for 70 participants with ASD that attended the clinic in a 3 month period.
Results: 14 (20%) of participants (11 male, 3 female) had chromosomal imbalances. Nine had a single chromosome deletion, and three a single duplication (two on chromosome 7). One participant had 2 deletions (chromosome 2), and one participant had both a deletion and a duplication. Of these patients, 8 met criteria for ASD on all three domains (diagnosed with ‘autism’ or Asperger syndrome), 3 met criteria for ASD on 2 domains (diagnosed with ‘atypical autism’), and 3 met criteria for Pervasive Developmental Disorder – not otherwise specified (ICD 10). The three female participants also met criteria for ADHD (DSM-IV). 3 male participants also had co-morbid diagnoses (hyperkinetic disorder, depression, and generalised anxiety)
Conclusions: Preliminary results suggest that approximately 20% of individuals with ASD assessed at a specialist clinic also had an underlying chromosomal abnormality detected by CGH analysis. However, the genes affected varied widely. We plan to present data from a larger 12 month sample at the conference investigating whether particular genetic variations (and the genes they involve) are associated with particular behavioural features of ASD.