Curvilinear Association Between Language Disfluency and FMR1 CGG Repeat Size Across the Normal, Intermediate, and Premutation Range.

摘要: Historically, investigations of FMR1 have focused almost exclusively on the clinical effects CGG expansion within categories premutation (55-200 repeats) and fragile X syndrome (>200 repeats). However, emerging evidence suggests that CGG-dependent phenotypes may occur across allele sizes traditionally considered "normal" range. This study adopted an individual-differences approach to determine association between language production ability repeat length full range normal, intermediate, alleles. Participants included 61 adult women with repeats (n = 37), intermediate (i.e., 41-54 repeats; n 2), or normal 6-40 22) ranges. All participants were biological mothers a child developmental disorder, control for potential parenting stress. Language samples collected frequency disfluencies interruptions in flow speech) served as index skills. Verbal inhibition skills, measured Hayling Sentence Completion Test, also examined correlate disfluency, consistent theoretical work linking disfluency inhibitory deficits Inhibition Deficit Hypothesis). Blood size. A general linear model tested size larger (allele-2) primary predictor covarying education level, IQ, age, other allele. robust curvilinear was detected, where low-normal (∼ <25 mid-premutation alleles (∼90-110 linked higher rates disfluency. Disfluency not associated deficits, which challenges prior deficit could account elevated FMR1-associated conditions. Findings suggest variation ability, evident individuals without expansions FMR1.