Is cone-rod dystrophy inherited ?
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.