Earlier detection of Fragile X syndrome made possible

By Dr. Ananya Mandal, MDJan 19 2012

Now families children with fragile X syndrome (FXS) may have a chance of earlier detection and intervention. The Murdoch Children's Research Institute breakthrough could allow newborn screening of the world's most common cause of inherited developmental disability. The research findings were published in the journal Clinical Chemistry.

The institute has developed a DNA test that would allow doctors to detect the type and severity of symptoms much earlier. Presently it can take doctors until a child turns three to diagnose the condition.

Lead researcher Dr David Godler said the discovery could pave the way for a simple, accurate and inexpensive test for FXS. The researchers say the test could become a fixture in newborn screening tests. Fragile X Association of Australia president John Kelleher said the test could help sufferers and their families with better treatment and improved outcomes.

“The genetics of it are there at birth so you can potentially test much earlier and tell parents, ‘This is what might happen, your kid might benefit from early intervention treatments and you yourself may go for genetic counseling’,” Dr Godler said. “We get families that might have three kids with Fragile X before they even know their first child has it,” he said.

The world-first Murdoch Children's research showed the new test could detect both the type and severity of symptoms in Fragile X Syndrome in DNA samples from 154 females. Dr Godler said those findings were now being validated in a larger international study. “It looks good but if we validate it with a much larger independent cohort it could go in a year or two into more common practice,” he said.

The genetic disorder is caused by a faulty switch in a gene called FMR1, which is on the X chromosome. A child born with Fragile X Syndrome, caused by a faulty gene on the X chromosome, typically develops an IQ below 70 and physical abnormalities. Their parents and grandparents can also be carriers of the faulty gene and display softer symptoms later in life.

It is estimated that one in 130 females and one in 180 males carry the gene. Each week in Australia one child is born who is fully affected with FXS.