Autistic Traits Associated with the Fragile X Premutation Allele: The Neurodevelopmental Profile.

Although most individuals who carry the Fragile X premutation allele, defined as 55-200 CGG repeats on the X-linked FMR1 gene (Fragile X Messenger Ribonucleoprotein 1 gene), do not meet diagnostic criteria for autism spectrum disorder, there is a suggestion of increased behaviors associated with subtle autistic traits. More autism associated characteristics have been reported among adults than children. This may highlight a possible worsening developmental trajectory, variable findings due to research quality or differences in number of studies done in adults vs children, rather than true developmental changes. This review is designed to examine the neurodevelopmental profile associated with the premutation allele from a developmental perspective, focused on autistic traits.

Reading skills over time among children with Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is an X-linked progressive neuromuscular disorder with a distinct cognitive profile including decreased verbal span. Children with DMD are also at risk for lower scores on academic achievement tests and increased behavioral problems. Longitudinal analyses generally reveal a stable intellectual profile, although attention and behavioral problems may negatively impact longitudinal IQ scores. To date, no study has reported on reading over time in DMD. Reading performance was assessed longitudinally in children with DMD, examining for potential contributions to the trajectory. Retrospective data analysis on assessments completed at baseline, year 2, and year 4 on 26 boys with DMD and 27 unaffected sibling controls (age at baseline: DMD 8 ± 1.4, controls 9 ± 2.6) indicated that children with DMD performed slightly, yet significantly, worse than controls on reading skills, but the longitudinal trajectory of reading skills for children with DMD and controls was not significantly different. Verbal span at time 1 was uniquely associated with later reading skills in children with DMD. Behavior was not associated with declines. The results confirm that children with DMD underperform on reading tasks and align with previous research suggesting that cognitive skills in DMD are stable over time.

Intrasubject variability of sustained attention is associated with elevated self-reported attention deficits in women with a fragile X premutation allele.

OBJECTIVE: Women with a fragile X premutation (PM) self-report higher rates of attention difficulties than women without a PM; however, results of studies using objective measures of attention are inconsistent. The present study assessed whether intrasubject variability during a sustained attention task better predicted functional outcomes in women with a PM than the previously published standard reaction time and accuracy variables. METHOD: We analyzed continuous performance test, a computerized measure of sustained attention, and the Conners' Adult Attention-Deficit/Hyperactivity Disorder Rating Scale Report (CAARS) data from 273 women with a PM and 175 women without a PM aged 18-50 years. Separate analyses using Pearson correlations and independent t tests were performed on the full range of coefficient of variation (CV) of reaction time scores and the subset of scores that showed higher variability. RESULTS: Performance variability of sustained attention measured by the continuous performance test was associated with functional outcomes measured by the CAARS in women with a PM but not women without a PM. Specifically, the CV in those with higher variability was correlated with two CAARS subscale scores (p = .006). Independent t tests showed significant differences in CV between CAARS scores dichotomized for the presence of subclinical symptoms for two subscales (p ≤ .001-.007). Correlation between the full range of CV scores and the CAARS Inattention/Memory Problems subscale approached significance (p = .012). CONCLUSIONS: Findings highlight the importance of including intrasubject variability in analyzing attention in clinical populations as a more sensitive objective measure associated with reported symptoms and to assist in predicting functional outcomes. (PsycInfo Database Record (c) 2024 APA, all rights reserved).