Study of USH1 splicing variants through minigenes and transcript analysis from nasal epithelial cells

Area of Science:

• Genetics
• Ophthalmology
• Otorhinolaryngology

Background:

• Usher syndrome type I (USH1) is a genetic disorder causing profound deafness, vestibular dysfunction, and early-onset vision loss.
• Accurate identification of pathogenic splicing variants is crucial for understanding USH1's molecular basis.

Purpose of the Study:

• To assess the pathogenicity of USH1 splicing variants using minigene assays and patient-derived nasal epithelial cells.
• To correlate splicing defects with clinical manifestations in USH1 patients.
• To evaluate nasal ciliary function in USH1 patients.

Main Methods:

• Bioinformatic analysis of putative splicing variants.
• Minigene assays to study mRNA processing.
• RT-PCR analysis of RNA from patient nasal epithelial cells.
• Measurement of nasal ciliary beat frequency.

Main Results:

• Eight USH1 variants in MYO7A, CDH23, and PCDH15 were confirmed to affect splicing.
• Minigene assays and nasal cell transcript analysis effectively identified pathogenic splicing variants.
• USH1 patients demonstrated significantly lower nasal ciliary beat frequency than controls.

Conclusions:

• Minigene assays and nasal cell RNA analysis are reliable methods for evaluating splicing variant pathogenicity in USH1.
• Splicing defects in USH1 genes contribute to the disease phenotype.
• Reduced nasal ciliary function is a potential characteristic of USH1.