Novel mutation in SLC4A7 gene causing autosomal recessive progressive rod-cone dystrophy

Area of Science:

• Ophthalmology
• Genetics
• Molecular Biology

Background:

• Inherited retinal dystrophies (IRDs) are a group of genetic disorders affecting photoreceptors.
• Rod-cone dystrophy, the most common IRD, primarily impacts rod photoreceptors.
• Advances in genetic sequencing have increased the diagnostic yield for IRDs, with over 80 causal genes identified.

Observation:

• A 66-year-old male presented with progressive night blindness and visual field constriction.
• Fundus examination revealed diffuse intraretinal pigment, retinal pigment epithelial atrophy, and stable visual acuity.
• Mild macular edema was observed and managed with topical dorzolamide.

Findings:

• Whole exome sequencing identified a homozygous frameshift mutation in the SLC4A7 gene.
• This novel mutation in SLC4A7, encoding a sodium bicarbonate cotransporter, leads to protein termination.
• The identified mutation is the first reported cause of rod-cone dystrophy linked to SLC4A7.

Implications:

• This case underscores the importance of SLC4A7 in photoreceptor function and retinal ion homeostasis.
• The findings expand the genetic landscape of inherited retinal dystrophies.
• This discovery may inform future diagnostic strategies and therapeutic targets for IRDs.