Study: Children with Gene Mutation Associated with Fragile X Experience Developmental Delays in First Two Years of Life

Early onset of developmental issues makes early detection of the gene mutation critical, researchers say

RESEARCH TRIANGLE PARK, N.C. — A new study from RTI International finds that children with fragile X syndrome (FXS) demonstrate significant developmental challenges within the first two years of life. The findings highlight the need for earlier identification of FMR1 gene mutations, which can lead to FXS, in order to allow interventions and therapeutics to have maximum effectiveness in combatting developmental issues.

“It’s well known in the scientific community that an FMR1 full mutation is associated with developmental delays,” said Anne Wheeler, Ph.D., a research public health analyst at RTI who led the study. “But is has not previously been clear how early symptoms present in young children. Our analysis shows that they are observable quite early in life.”

Wheeler and her colleagues combed through data from eight unique studies that used the Mullen Scales of Early Learning to assess children with an FMR1 gene mutation and created a dataset with 1,178 observations from more than 500 young children. 

The data revealed that males with a full mutation showed delays in early learning, motor skills and language development as young as six months, and both sexes with a full mutation were delayed on all developmental domains by 2 years old.

Males with a full mutation continued to gain skills over early childhood at around half the rate of their typically developing peers, while females with a full mutation showed growth at around three-quarters the typical rate.

Children with a premutation, which is an FMR1 gene change typically associated with conditions that develop in adulthood, were mostly typical in their developmental profiles and trajectories. However,  results suggested a higher than expected prevalence of delays in fine motor skills by 18 months in boys with a premutation.

“The bottom line is that the earlier we detect the FMR1 gene mutation in children, the earlier they can receive much-needed interventions to potentially avoid severe developmental delays,” added Wheeler. “Following recommended developmental screening and genetic testing guidelines will aid in early diagnosis.”

For more information about RTI’s newborn screening research and Early Check, a program that offers free screening for fragile X syndrome and other conditions for newborns in North Carolina, visit: www.rti.org/centers/newborn-screening.