Language impairment with a microduplication in 1q42.3q43.

Area of Science:

• Genetics
• Neurodevelopmental Disorders
• Human Molecular Genetics

Background:

• Distal chromosome 1 long arm deletions and duplications are linked to brain abnormalities and developmental delay.
• Duplications in this region are less common, limiting understanding of associated cognitive and language profiles.
• This study focuses on a rare, small interstitial duplication at 1q42.3q43.

Purpose of the Study:

• To report the cognitive and language capacities of an individual with a minimal 1q42.3q43 duplication.
• To identify potential candidate genes contributing to the observed neurodevelopmental deficits.
• To investigate the impact of this specific genetic alteration on speech, language, and cognitive functions.

Main Methods:

• Detailed case study of a proband with a 1q42.3q43 duplication (arr[hg19] 1q42.3q43(235,963,632-236,972,276)x3).
• Comprehensive assessment of cognitive and language abilities, including speech, phonology, verbal auditory memory, lexical and grammatical knowledge, and pragmatic skills.
• Genetic analysis to identify candidate genes within and outside the duplicated region, comparing gene expression with healthy parents.

Main Results:

• The proband exhibits severe speech impairment with dysarthric features and a phonological deficit rooted in verbal auditory memory impairment.
• Expressive and receptive language abilities are negatively impacted, likely secondary to the phonological deficit.
• Pragmatic abilities appear significantly spared, indicating preserved conversational skills.
• Candidate genes identified include LYST (in the duplicated region), CMIP, DDIT4, SLC29A1, and CNTNAP3, with altered expression levels.

Conclusions:

• The 1q42.3q43 duplication is associated with significant speech and language deficits, particularly affecting verbal auditory memory and phonological processing.
• LYST, CMIP, DDIT4, SLC29A1, and CNTNAP3 are proposed as candidate genes potentially responsible for the observed neurodevelopmental phenotype.
• Further research is warranted to elucidate the precise roles of these genes in speech and language development.