Question: How many people are affected by cone-rod dystrophy ?
Answer: Cone-rod dystrophy is estimated to affect 1 in 30,000 to 40,000 individuals.
Source: GHR

Question: What are the genetic changes related to cone-rod dystrophy ?
Answer: Mutations in approximately 30 genes are known to cause cone-rod dystrophy. Approximately 20 of these genes are associated with the form of cone-rod dystrophy that is inherited in an autosomal recessive pattern. Mutations in the ABCA4 gene are the most common cause of autosomal recessive cone-rod dystrophy, accounting for 30 to 60 percent of cases. At least 10 genes have been associated with cone-rod dystrophy that is inherited in an autosomal dominant pattern. Mutations in the GUCY2D and CRX genes account for about half of these cases. Changes in at least two genes cause the X-linked form of the disorder, which is rare. The genes associated with cone-rod dystrophy play essential roles in the structure and function of specialized light receptor cells (photoreceptors) in the retina. The retina contains two types of photoreceptors, rods and cones. Rods are needed for vision in low light, while cones provide vision in bright light, including color vision. Mutations in any of the genes associated with cone-rod dystrophy lead to a gradual loss of rods and cones in the retina. The progressive degeneration of these cells causes the characteristic pattern of vision loss that occurs in people with cone-rod dystrophy. Cones typically break down before rods, which is why sensitivity to light and impaired color vision are usually the first signs of the disorder. (The order of cell breakdown is also reflected in the condition name.) Night vision is disrupted later, as rods are lost. Some of the genes associated with cone-rod dystrophy are also associated with other eye diseases, including a group of related eye disorders called rod-cone dystrophy. Rod-cone dystrophy has signs and symptoms similar to those of cone-rod dystrophy. However, rod-cone dystrophy is characterized by deterioration of the rods first, followed by the cones, so night vision is affected before daylight and color vision. The most common form of rod-cone dystrophy is a condition called retinitis pigmentosa.
Source: GHR

Question: Is cone-rod dystrophy inherited ?
Answer: Cone-rod dystrophy is usually inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. Less frequently, this condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most of these cases, an affected person has one parent with the condition. Rarely, cone-rod dystrophy is inherited in an X-linked recessive pattern. The genes associated with this form of the condition are located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. Females with one copy of the altered gene have mild vision problems, such as decreased visual acuity. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
Source: GHR

Question: What are the treatments for cone-rod dystrophy ?
Answer: These resources address the diagnosis or management of cone-rod dystrophy: - Cleveland Clinic: Eye Examinations: What to Expect - Genetic Testing Registry: CONE-ROD DYSTROPHY, AIPL1-RELATED - Genetic Testing Registry: Cone-rod dystrophy - Genetic Testing Registry: Cone-rod dystrophy 1 - Genetic Testing Registry: Cone-rod dystrophy 10 - Genetic Testing Registry: Cone-rod dystrophy 11 - Genetic Testing Registry: Cone-rod dystrophy 12 - Genetic Testing Registry: Cone-rod dystrophy 13 - Genetic Testing Registry: Cone-rod dystrophy 15 - Genetic Testing Registry: Cone-rod dystrophy 16 - Genetic Testing Registry: Cone-rod dystrophy 17 - Genetic Testing Registry: Cone-rod dystrophy 18 - Genetic Testing Registry: Cone-rod dystrophy 19 - Genetic Testing Registry: Cone-rod dystrophy 2 - Genetic Testing Registry: Cone-rod dystrophy 20 - Genetic Testing Registry: Cone-rod dystrophy 21 - Genetic Testing Registry: Cone-rod dystrophy 3 - Genetic Testing Registry: Cone-rod dystrophy 5 - Genetic Testing Registry: Cone-rod dystrophy 6 - Genetic Testing Registry: Cone-rod dystrophy 7 - Genetic Testing Registry: Cone-rod dystrophy 8 - Genetic Testing Registry: Cone-rod dystrophy 9 - Genetic Testing Registry: Cone-rod dystrophy X-linked 3 - Genetic Testing Registry: Cone-rod dystrophy, X-linked 1 - MedlinePlus Encyclopedia: Color Vision Test - MedlinePlus Encyclopedia: Visual Acuity Test - MedlinePlus Encyclopedia: Visual Field Test These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
Source: GHR