In a new study, researchers found a new stand-alone test can more precisely diagnose people with a common genetic cause of autism than the current tests.
The new test is a more cost-effective, accurate and timely way to identify those with Fragile X syndrome, one of the most common genetic causes of intellectual disability and autism.
The research was led by the Murdoch Children’s Research Institute.
Fragile X associated costs to raise one affected child have been estimated at more than $2.5 million to the health system.
The genetic syndrome affects about one in 4,000 children with about 90,000 Australians and over one million Americans impacted in some way.
A large proportion of these are women who themselves are not affected with Fragile X, but carry a DNA ‘premutation’ in their FMR1 gene.
This premutation predisposes these women to have children with Fragile X.
A major issue with Fragile X is that at a young age the syndrome is not clinically distinct, with an average age of diagnosis in Australia about five years, and, according to the Centers for Disease Control and Prevention, over three years in the US.
As a result of delayed diagnosis, affected children do not receive the medical care they need in a timely manner, and families may end up having multiple affected children before they receive a diagnosis for their first child.
In the study, the team developed a new test called Methylation Specific Quantitative Melt Analysis (MS-QMA).
This is a one-step process, to assist in the more accurate and timely diagnosis of Fragile X in affected children referred for genetic testing.
The one-step test looks at the number of chemical modifications or “marks,” called methylation, added to a patient’s FMR1 gene in Fragile X, which are not present in typically developing children without Fragile X syndrome.
Increasing these marks reduces the production of a protein called FMRP required for healthy brain development and function.
This study for the first time shows that the number of these marks can be increased, even in people without the usual genetic changes seen in Fragile X syndrome (called CGG repeats).
The team hopes their new test could improve genetic diagnostic precision and could benefit families and their children.
The lead author of the study is MCRI’s Associate Professor David Godler.
The study is published in Scientific Reports.
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