Is Newborn Screening for Fragile X Syndrome Desirable?

Screening newborn boys for fragile X syndrome is feasible as part of standard neonatal screening — both the full syndrome and premutations are detectable.

Fragile X syndrome (FXS) is the most common hereditary form of intellectual disability. In a pilot study intended to explore the feasibility of screening newborns for FXS, researchers collected blood samples from 1459 newborn males at the time of standard newborn metabolic screening.

Abnormalities of the X chromosome were found in five cases: one aneuploidy (47, XXY); two premutations (55–200 trinucleotide repeats), which are not associated with mental retardation but predispose to late-onset tremors and ataxia; and two full mutations (>200 trinucleotide repeats), which are expected to lead to full FXS, with moderate mental retardation as the infant gets older. The observed rate of FXS (1/730) was much higher than the established rates of 1/…

Reviewing Author

Judith G. Hall, OC, MD