The prevalence of the FMR1 and FMR2 mutations among preschool children with language delay

M. M.M. Mazzocco, G. F. Myers, J. L. Hammer, R. Panoscha, B. K. Shapiro, A. L. Reiss

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We examined the prevalence of the fragile X mental retardation (FMR1) full mutation and fragile X E mutation (FMR2) among preschoolers evaluated for language delay. A total of 534 preschoolers recruited from a Developmental Pediatric or Speech and Language Disorders clinic were tested with Southern blot and polymerase chain reaction DNA analyses; 3 were found to have the FMR1 full mutation. None of the 534 children tested positive for the FMR2 full mutation; however, 3 children had unusually small FMR2 alleles suggestive of FMR2 deletions. Screening for fragile X among language-delayed preschoolers is warranted, particularly when there is a family history of mental retardation, but regardless of sex or the presence of behavioral or physical features associated with the fragile X phenotype. The potential benefit of screening for FMR2 alterations is an unexpected implication of the study and is worthy of continued exploration.

Original languageEnglish (US)
Pages (from-to)795-801
Number of pages7
JournalJournal of Pediatrics
Issue number5
StatePublished - Jan 1 1998


ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health

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