Newborn Screening Program for Fragile X Syndrome to Be Launched

The first systematic newborn screening program for the genetic mutation that results in fragile X syndrome--the single most common known genetic cause of autism and mental retardation--is to be launched.

Fragile X syndrome and its associated disorders are the result of a mistake in the number of repeats of three nucleotides in the FMR1 gene on the X chromosome. A normal X chromosome generally has up to 55 repeats of these trinucleotides. Repeats above 200 result in fragile X syndrome. The new test employs an inexpensive polymerase chain reaction (PCR) technique that amplifies the expansion of the FMR1 gene, allowing scientists to detect the number of nucleotide repeats, from normal number of repeats to the full fragile X mutation of 200 repeats or more.

Children with fragile X syndrome suffer from physical anomalies, intellectual deficits, learning disabilities, and behavioral and psychiatric problems that are not diagnosed right away. Current diagnostic tests for fragile X are limited by expense and could not be offered as newborn screening tests.

The new test can identify the fragile X mutation using small drops of blood collected from infants after birth. Developed by scientists from the University of California (UC), Davis (Sacramento, CA, USA), the test was validated at Rush University Medical Center (Chicago, IL, USA). All newborns at Rush and UC Davis will undergo the test with the goal of screening as many as 30,000 infants during the next five years. The study will lay the groundwork for universal newborn screening of all infants in the United States for early detection of the fragile X mutation.

"While the newborn screening study is not specifically designed to offer treatment, the diagnosis will open the door to new therapies for infants,” said Dr. Randi Hagerman, study senior investigator and medical director of the Medical Investigation of Neurodevelopmental Disorders (MIND) Institute at University of California, Davis (Sacramento, CA, USA). "Once we have identified affected infants, we will propose treatment options for them.”

Related Links:
University of California, Davis
Rush University Medical Center
MIND Institute at UC Davis