A Family Study of Copy Number Variations in Patients With Autism Spectrum Disorder

Due to its high prevalence, long-term impairment, high genetic component (heritability > 90%), and lack of effective prevention and treatment, ASD has been prioritized for genetic studies. However, despite extensive genetic research, there has been no any conclusive result mainly due to the clinical and genetic heterogeneity of ASD. Given the progress of CNV study in ASD, several challenges remain to be faced with, such as differences in phenotypic definition across different studies; a lack of population norms for CNVs, and a lack of consensus in methods for CNV detection and analysis. In the present study, the large segments of CNV found in ASD probands will be compared with standardized controls from National Center for Genome Medicine (NCGM), Academia Sinica to identify the possible CNVs. The other important issue of CNV research in ASD is to investigate whether the origin of CNVs are inherited or de novo. By collecting the complete background and revealing the CNVs of the parents and siblings, the origin of the CNVs will be uncovered in the present project. The candidate genes from important CNVs will be identified by pathway analysis. Gene expression will be conducted to confirm the pathogenic genes. Notably the present study will help bridge the gap to translate the bench findings to bedside to help early detection of ASD and pave the way developing effective treatment for ASD in the future.

Specific Aims:

With the above-mentioned rationale of this project and limited research budget from NSC, the ultimate goal of this project is to identify the important CNVs to reveal the pathogenic genes for ASD for future translational research in ASD and to prospectively characterize clinical features of ASD individuals with CNV.

The specific aims of this study are as follows,

• To identify important and pathogenic CNVs by comparing the CNVs and CNPs of the controls provided by NCGM , Academia Sinica;
• To assess parents and siblings of ASD patients who were found to have ~500 kb CNVs in our previous study using clinical, psychopathological, and social measures for family study and also to conduct CNV analysis in the families to determine the origin of the CNVs;
• To conduct a follow-up assessments of clinical features, and social and neuropsychological functions of ASD probands with CNV to examine the phenotype changes over time;
• To study the clinical phenotypes between de novo and inherited groups to reveal the pathogenic CNVs;
• To conduct pathway analysis of genes involved in the CNVs, and to confirm the pathogenic genes by conducting gene expression analysis;
• To investigate the associations of clinical phenotypes such as autistic tendency, and social impairments between (1) probands with/without CNVs/controls, and (2) probands/unaffected siblings/controls.

Inclusion criteria

• subjects have a clinical diagnosis of autistic disorder or Asperger disorder defined by the DSM-IV and ICD-10 criteria and ASD defined by the DSM-5, which was made by board-certificated child psychiatrists at the first visit and following visits;
• their ages range from 3 to 30;
• subjects have at least one biological parent;
• both parents are Han Chinese; and
• subjects and their biological parents consent to participate in this study for complete phenotype assessments and blood withdraw for genetic study.

Exclusion criteria

• if they currently meet criteria or have a history of the following condition as defined by DSM-IV: Schizophrenia, Schizoaffective Disorder, or Organic Psychosis.