Characterization and Engineered U1 snRNA Rescue of Splicing Variants in a Turkish Neurodevelopmental Disease Cohort

Area of Science:

• Genetics
• Molecular Biology
• Rare Diseases

Background:

• Rare neurodevelopmental disorders (RNDDs) are a significant subset of rare diseases.
• Accurate variant classification is crucial for RNDD diagnosis and management, but challenging for splice-altering variants.
• Existing in silico tools struggle with noncanonical splice site variants.

Purpose of the Study:

• To assess the pathogenicity of seven previously proposed splicing variants in RNDDs using in vitro assays.
• To explore the therapeutic potential of engineered U1 small nuclear RNAs (snRNAs) for correcting splicing defects in RNDDs.

Main Methods:

• Minigene assays were used to evaluate the splicing effects of seven candidate variants.
• Engineered U1 snRNAs were tested for their ability to correct splicing defects in HeLa cells using minigene plasmids.

Main Results:

• Six of the seven tested variants demonstrated moderate to strong effects on pre-mRNA splicing.
• Engineered U1 snRNAs partially corrected splicing defects in four of the studied genes to varying extents.

Conclusions:

• In vitro minigene assays are valuable for reclassifying variants of uncertain significance affecting splicing.
• Modified U1 snRNAs hold therapeutic promise for treating RNDDs caused by specific splicing abnormalities.