Lineagen, based in Salt Lake City, offers diagnostic testing services for autism spectrum disorders (ASD). The company’s first commercial offering is the FirstStepDx PLUS® test, which provides physicians with a fully integrated genetic testing, counseling, and developmental screening service to aid in the clinical evaluation of children with autism spectrum disorder (ASD) or other forms of developmental delay.
Lineagen's FirstStepDx PLUS® test for ASD and other developmental disorders of childhood is a chromosomal microarray (CMA) genetic test intended to detect ASD earlier and more efficiently. Note that the company indicates that the test includes genetic counseling, the most advanced, customized CMA clinically available, and a detailed, personalized report created specifically for each individual tested. The test is specifically designed to help parents, physicians, and other healthcare providers significantly shorten the time for clinical action, allowing access to proven clinical management and treatment approaches as early as possible.
The test uses a custom-designed CMA platform that consists of 1,953,246 unique nonpolymorphic probes and 743,304 SNP probes that come standard on the Affymetrix CytoScan™ HD microarray, with an additional 83,443 custom probes designed by Lineagen. Lineagen’s custom probes are designed to provide higher resolution coverage in genomic regions with scientific evidence supporting their clinical relevance.
The FirstStepDx PLUS® test provides high-resolution, whole-genome CMA to identify genetic variations (eg, duplication or deletion syndromes) that may contribute to ASD and other childhood developmental disorders. The test is employed as part of an integrated service that combines proprietary genetic testing, reporting, and genetic counseling.
Limitations:
It is important to note that the FirstStepDx PLUS® test for ASD does have limitations. First, there is the inability to determine whether a copy number change (eg, deletion or duplication) is de novo or inherited. A de novo mutation or alteration is one that is present for the first time in one family member because of a variant in a germ cell (egg or sperm) or a variant that arises in the fertilized egg itself.
Secondly, the testing does not rule-out all possible genetic conditions, specifically those caused by point mutations or gene expansions. In addition, the CMA methodology does not directly assess the mitochondrial genome (mtDNA) and thus cannot rule-out mitochondrial disorders.
NextStepDx PLUS®
In mid-2014, Lineagen announced plans to launch a new test, called NextStepDx PLUS®, as a reflex test to compliment the FirstStepDx PLUS® test for ASD, developmental delay, and other childhood developmental disorders. NextStepDx PLUS® is intended to increase the detection rate to up to 50% by scanning for disease-relevant, single-nucleotide variants that the FirstStepDx PLUS® test does not cover.
