Overview of Vision Impairment and Inherited Retinal Diseases (IRDs)
Vision is essential for daily activities like learning, working, and connecting with others. More than 2.2 billion people suffer from vision impairment due to various causes, including inherited retinal diseases (IRDs).
- IRDs are genetic conditions caused by mutations in over 300 genes affecting retina function, leading to progressive vision loss or blindness.
- Globally, approximately 5.5 million people are affected by IRDs.
- Prevalence in India is notably higher:
- 1 in 372 in rural South India
- 1 in 930 in urban South India
- 1 in 750 in rural Central India
- Early intervention can mitigate or prevent blindness progression.
Gene Therapy and RNA-based Therapeutics
Gene Therapy
- In 2017, the FDA approved the first gene therapy for blindness from RPE65 gene mutations.
- Over 50 clinical trials are investigating gene therapy for various inherited eye disorders.
RNA-based Therapies
RNA-based therapies present a promising alternative for treating genetic disorders, including IRDs, due to their temporary changes that reduce long-term risks.
- Antisense Oligonucleotides (ASOs):
- Used successfully for spinal muscular atrophy and Duchenne muscular dystrophy.
- Being explored for retinal conditions like Stargardt disease, Leber congenital amaurosis, and retinitis pigmentosa.
- ADAR Enzyme-based RNA Editing:
- Corrects specific mutations at the RNA level.
- Potentially restores protein production in retinal cells without altering DNA.
- Suppressor tRNAs:
- Bypasses stop-codon mutations to enable full-length protein production.
- Restores retinal function in IRD patients.
- PTC124 (Ataluren):
- Used for cystic fibrosis and Duchenne muscular dystrophy.
- Clinical trials are underway for its use in treating aniridia.
Precision Medicine and Genetic Research in India
- India's diverse population poses challenges in mapping genetic mutations, necessitating extensive research.
- Barriers include limited awareness, inadequate genetic counselling, insufficient funding, and restricted diagnostic access in rural areas.