Cone Dystrophy 3

Background and History: 

The retina is the light-sensing tissue in the back of the eye.  It contains both rods which allow us to see in dim light and cones which respond to color.  Together these cells enable us to see the world around us in both color and black-and-white.

Mutations in a large number of genes affect the function and health of these cells of the retina and cause disorders such as colorblindness and night blindness.  Some gene alterations impact primarily cones and others mainly affect the rods.  In most cases, however, both rods and cones are impacted. 

Clinical Correlations: 

This condition is called a cone dystrophy since early symptoms of vision and color perception indicate primarily damage to the cones.  Symptoms begin between the ages of 20 and 40.  This is a progressive disorder as vision becomes worse with age and most patients eventually are legally blind.  Eventually though the rods deteriorate as well and there may be some loss of night vision.  No systemic disease has been associated with this cone dystrophy. 


A mutation on chromosome 6 is responsible for this condition.  It follows an autosomal dominant pattern of inheritance and the disease is transmitted from parent to child with a 50% chance in each child. 

Diagnosis and Prognosis: 

The diagnosis is made by an ophthalmologist based on examination of the eye and an ERG (electroretinogram) test.  The prognosis for vision is poor as most patients eventually become blind.  In early stages, low vision aids can be helpful. 

Additional Information
Autosomal dominant