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GUCY2D gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

GUCY2D gene

The GUCY2D gene provides instructions for making a protein essential for vision, specifically involved in the process of phototransduction within the retina.

Normal Function

The GUCY2D gene provides instructions for making a protein that plays an essential role in normal vision. This protein is found in the retina, the specialized tissue at the back of the eye that detects light and color. Within the retina, the GUCY2D protein is located in light-sensing cells called photoreceptors, which include rods (needed for low-light vision) and cones (needed for bright light and color vision).

The GUCY2D protein is involved in phototransduction. During this process, light entering the eye triggers chemical reactions that close channels in photoreceptor cell membranes, producing an electrical signal interpreted by the brain as vision. After stimulation, the GUCY2D protein helps re-open these channels, returning the photoreceptors to their "dark" state so they can be stimulated again.

Health Conditions Related to Genetic Changes

Cone-rod dystrophy

Pathogenic variants in the GUCY2D gene can cause cone-rod dystrophy type 6. This disorder affects the retina and causes vision loss that may worsen over time, typically developing later in life and gradually affecting central, color, night, and peripheral vision.

Many of these variants involve the replacement of the amino acid arginine at position 838. This change impairs phototransduction, causing photoreceptors to break down over time, leading to progressive vision loss.

Leber congenital amaurosis

Pathogenic variants in the GUCY2D gene can also cause Leber congenital amaurosis type 1, a group of eye disorders characterized by severe vision loss beginning in infancy. These variants account for 10 to 20 percent of all cases of Leber congenital amaurosis.

Many of these variants cause cells to produce an abnormally short, nonfunctional version of the GUCY2D protein. Without this protein, photoreceptor cells cannot return to their dark state after light exposure, disrupting phototransduction and leading to severe visual impairment.

Autosomal recessive congenital stationary night blindness

The GUCY2D gene is also associated with autosomal recessive congenital stationary night blindness.

Other Names for This Gene

  • CYGD
  • LCA1
  • Leber congenital amaurosis 1
  • retGC
  • RETGC-1
  • retinal guanylate cyclase 1
  • rod outer segment membrane guanylate cyclase
  • ROS-GC
  • ROS-GC1

Genomic Location

The GUCY2D gene is found on chromosome 17.

Frequently Asked Questions

GUCY2D-related conditions like Leber congenital amaurosis and cone-rod dystrophy are typically inherited in an autosomal recessive pattern. This means a child must inherit two copies of the altered gene (one from each parent) to develop the condition. If you have one altered copy, you are a carrier and usually do not have symptoms, but each child you have with another carrier would have a 25% chance of inheriting both altered copies and developing the condition.
If you have a GUCY2D-related condition, any sudden or significant worsening of vision, new onset of severe light sensitivity (photophobia), changes in color perception, or increased difficulty seeing in low light or at night should prompt immediate consultation with your ophthalmologist. These could indicate progression or other eye issues requiring attention.
Currently, there are no approved cures for vision loss caused by GUCY2D gene changes. However, research into gene therapy and other treatments is ongoing, particularly for Leber congenital amaurosis. Management often focuses on supportive care, low-vision aids, and regular monitoring by an ophthalmologist to help individuals adapt to their vision loss.
GUCY2D-related Leber congenital amaurosis (LCA) typically causes severe vision loss starting in infancy, often affecting central and peripheral vision from a very young age. In contrast, GUCY2D-related cone-rod dystrophy usually develops later in life, causing progressive vision loss that gradually worsens over time, affecting central, color, night, and peripheral vision.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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