Objective:

To identify new genetic causes of retinitis pigmentosa (RP) and expand the diagnostic capabilities for this inherited retinal disease.

Key Findings:

• Heterozygous de novo and inherited dominant variants in RNU4-2 and four RNU6 paralogs cause nonsyndromic autosomal dominant RP.
• Pathogenic variants were identified in 153 individuals from 67 families.
• Recurrent 'hotspot' changes were found in a conserved structural region of the U4/U6 duplex.
• Affected individuals typically presented with classical RP phenotype, with symptom onset in adolescence.
• Associated findings included cystoid macular edema (55.9%), non-age-related lens opacities (23.6%), and vitreomacular complications (30.6%).

Interpretation:

The discovery of snRNA variants as contributors to RP suggests that future diagnostic efforts should include these genes, particularly for unresolved cases.

Limitations:

• The study only accounts for approximately 1.4% of previously undiagnosed RP cases.
• Further research is needed to fully understand the role of snRNA genes in RP.

Conclusion:

This study highlights the importance of noncoding RNA in the genetics of RP and suggests a shift in focus for future genetic research in retinal diseases.