Certain conclusions can be made regarding genetic testing for ASD and include the following:
- The prevalence of ASD in the United States (US), estimated to be one in 68 births, is on the increase. ASD is the fastest-growing developmental disability in the US. While the cost of lifelong care for individuals with ASD can be significant, this cost can be reduced by two thirds with early diagnosis and intervention.
- The signs and symptoms of ASD, which can begin in early childhood and typically continue throughout the life of the affected individual, are varied and can include many abnormal behavioral characteristics.
- Although the exact cause or causes of ASD are not know, most experts tend to believe that there may be many different risk factors that can make a child more likely to have an ASD (including environmental, biologic, and genetic factors).
- There is no specific medical test or tests presently available to diagnose ASD. Typically, an examination of the child's behavior and development is used to make the diagnosis of ASD based the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria. In recent years, there is an increasing interest and support for the use of genetic testing to assess ASD and other developmental delay disorders. With improved technology, several specific genetic tests and gene panels are now available to help in the diagnosis of ASD.
- Genetic testing for autism, ASD, and other developmental delay disorders are commonly performed using next generation sequencing (NGS) or chromosomal microarray analysis (CMA) or a combination of both techniques.
- NGS is also known as high-throughput DNA sequencing. It is a powerful platform that has enabled the sequencing of thousands to millions of DNA molecules simultaneously. NGS can be used to determine the sequence of individual genes, larger genetic regions or clusters of genes (operons), full chromosomes, or entire genomes.
- CMA is a molecular technique that relies on a competition between labeled patient and reference DNA for hybridization to an array of immobilized target sequences. Microarray refers to a microchip-based testing platform that allows high-volume, automated analysis of many pieces of DNA at once. CMA chips use labels or probes that bond to specific chromosome regions. Computer analysis is used to compare a patient's genetic material to that of a reference sample.
