Lineagen has reported that its DNA test for the developmental disorder fragile X syndrome has specificity and sensitivity close to 100% and could enable earlier diagnosis.
The Salt Lake City-based company specializes in genetic testing for autism spectrum disorder and other conditions associated with developmental delays.
Its Methylation Specific Quantitative Melt Analysis (MS-QMA) diagnostic is a one-step test for methylation in the FMR1 gene, the hallmark of fragile X. The company sees this as an advance over current testing, which initially involves polymerase chain reaction (PCR) for expansion of an unstable CGG repeat sequence in the FMR1 gene, followed by determination of FMR1 promoter methylation status using the AmplideX mPCR test (Asuragen) with or without a Southern blot analysis. The second step of the process is expensive, so it is reserved for those who test positive on the CGG repeat test, but the company noted that some children with the condition will be missed on the first screen, resulting in a delayed diagnosis.
Experience with the MS-QMA test in more than 300 pediatric patients from centers in the U.S. and Australia was published on October 25 in Scientific Reports. Senior author David Godler, PhD, from Murdoch Children's Research Institute, and colleagues described how the MS-QMA test provides a new understanding of fragile X syndrome. According to the company, it is possible to identify up to 15% more patients with the condition using MS-QMA instead of the CGG repeat test.
The study was funded by grants in Australia, including support from the Victoria state government's Operational Infrastructure Support Program, the Murdoch Children's Research Institute, and the Royal Children's Hospital Foundation.