Elsevier

Biological Psychiatry

Volume 90, Issue 11, 1 December 2021, Pages 742-755
Biological Psychiatry

Archival Report
Developmental and Behavioral Phenotypes in a Mouse Model of DDX3X Syndrome

https://doi.org/10.1016/j.biopsych.2021.05.027Get rights and content
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open access

Abstract

Background

Mutations in the X-linked gene DDX3X account for approximately 2% of intellectual disability in females, often comorbid with behavioral problems, motor deficits, and brain malformations. DDX3X encodes an RNA helicase with emerging functions in corticogenesis and synaptogenesis.

Methods

We generated a Ddx3x haploinsufficient mouse (Ddx3x+/− females) with construct validity for DDX3X loss-of-function mutations. We used standardized batteries to assess developmental milestones and adult behaviors, as well as magnetic resonance imaging and immunostaining of cortical projection neurons to capture early postnatal changes in brain development.

Results

Ddx3x+/− females showed physical, sensory, and motor delays that evolved into behavioral anomalies in adulthood, including hyperactivity, anxiety-like behaviors, cognitive impairments in specific tasks (e.g., contextual fear memory but not novel object recognition memory), and motor deficits. Motor function declined with age but not if mice were previously exposed to behavioral training. Developmental and behavioral changes were associated with a reduction in brain volume, with some regions (e.g., cortex and amygdala) disproportionally affected. Cortical thinning was accompanied by defective cortical lamination, indicating that Ddx3x regulates the balance of glutamatergic neurons in the developing cortex.

Conclusions

These data shed new light on the developmental mechanisms driving DDX3X syndrome and support construct and face validity of this novel preclinical mouse model.

Keywords

Corticogenesis
DDX3X syndrome
Intellectual disability
Movement disorder
Neurodevelopment

Cited by (0)

1

AB and MG-F contributed equally to this work.