Stargardt macular degeneration
Stargardt macular degeneration is a genetic eye disorder that causes progressive vision loss by damaging the macula, the small area of the retina responsible for sharp, detailed vision.
Overview
Stargardt macular degeneration affects the retina, the light-sensitive tissue at the back of the eye. Specifically, it targets the macula, which is essential for tasks like reading, driving, and recognizing faces. In most cases, a fatty yellow pigment called lipofuscin accumulates in cells underlying the macula, eventually damaging the cells critical for clear vision.
Symptoms
Signs and symptoms typically appear in late childhood to early adulthood and worsen over time. These include:
- Progressive vision loss.
- Problems with night vision, making navigation in low light difficult.
- Impaired color vision.
Causes
The condition is primarily caused by variants in the ABCA4 gene, and less frequently by variants in the ELOVL4 gene.
- ABCA4 gene: This gene produces a protein that transports toxic substances out of photoreceptors. When the protein is dysfunctional, these substances build up as lipofuscin, leading to cell death.
- ELOVL4 gene: This gene is involved in creating very long-chain fatty acids. Variants lead to the formation of protein clumps (aggregates) that interfere with retinal cell function.
Inheritance
The inheritance pattern depends on the gene involved:
- ABCA4 variants: Inherited in an autosomal recessive pattern, where both copies of the gene must have a variant.
- ELOVL4 variants: Inherited in an autosomal dominant pattern, where one copy of the altered gene is sufficient to cause the disorder.