# Language Development in Fragile X Syndrome

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2020 · $618,682

## Abstract

Fragile X syndrome (FXS) is the leading inherited cause of intellectual disability, resulting from a mutation in
the FMR1 gene on the X chromosome. Males are more severely affected on average than females. Language
impairments are common and often more severe than cognitive-level expectations. These language
impairments interfere with the acquisition of literacy skills, learning, social interaction, and adaptive functioning.
The proposed project extends the previously funded, Language Development in Fragile X Syndrome. We will
continue the longitudinal investigation of males with FXS into adulthood and begin tracking the trajectories of
females with FXS, who have been under-studied, especially in the adult years. We will focus on language
development within the broader framework of an examination of the transition from high school into adulthood
and the experiences of individuals with FXS in contexts requiring and promoting independence. We also
propose to expand our assessment of language to include measures of pragmatics and literacy, which are
areas of challenge, even for females with FXS who do not have an intellectual disability. The project has four
specific aims. (1) Describe the development of language, literacy, and the capacity for independent functioning
in FXS during the transition into adulthood. We will use a variety of measurement strategies and provide the
most comprehensive characterization to date of the transition to adulthood for FXS. (2) Evaluate for the first
time the bidirectional relationships between the capacity for independent functioning and language and literacy.
(3) Identify the determinants of within-syndrome variation in language and literacy. In doing so, we will
emphasize the contributions of core domains of the FXS behavioral phenotype (i.e., auditory memory,
executive function, autism symptom severity, anxiety, social avoidance, and physiological arousal), as well as
the contributions of variations in the FMR1 mutation and the family context. (4) Identify sex differences in
language, literacy, and the capacity for independent functioning, which are areas that have yet to be explored
for the adult transition years. The target sample is 60 males and 60 females. Participants will enroll in the
project in their last year of high school, which occurs between ages 17 and 22 for this population. A
comprehensive, direct, multimethod, assessment of language, literacy, core features of the phenotype, the
capacity for independent functioning, and the family context (with an emphasis on parental contributions) will
be conducted near high school exit (T1) and then again three years later (T4). Molecular measures of the
FMR1 locus will be collected at T1. Caregiver report about the level of independence displayed by the
individual with FXS in meeting the demands of adult life will be collected at T1 and then annually (T2 through
T4). Participating sites are University of California, Davis; University of South Carolina; and V...

## Key facts

- **NIH application ID:** 9971542
- **Project number:** 5R01HD024356-26
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** LEONARD J. ABBEDUTO
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $618,682
- **Award type:** 5
- **Project period:** 1987-09-01 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9971542

## Citation

> US National Institutes of Health, RePORTER application 9971542, Language Development in Fragile X Syndrome (5R01HD024356-26). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/9971542. Licensed CC0.

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