Genetic Causes of Intellectual Disabilities: Cockayne Syndrome Disease
In 1946, a physician named Edward Cockayne discovered this condition. This rare genetic disorder involves defective CSA and CSB genes on chromosome 5. CSA and CSB genes are proteins that the body needs for DNA repair. The lack of these proteins manifests as premature aging. The aging process is significantly accelerated with exposure to sunlight, specifically UV radiation. Cockayne condition differs from other DNA repair disorders in that cancer is not associated with the syndrome.
Physical features include a short physique with disproportionately long limbs. Hands and feet tend to be quite large. The head is unusually small. Eyes are often sunken. The ears are usually deformed. The disorder is associated with dwarfism.
Individuals with Cockayne syndrome tend to have visual problems. These problems stem from retinal degeneration or optic nerve atrophy. They often have difficulty closing their eyelids completely. As a result, they suffer from dryness of the eye. Dry eyes affect vision acuity. Hearing problems are common. These problems are caused by neurons that progressively deteriorate. This hearing deterioration is the same as occurs with normal aging.
Unfortunately, Cockayne syndrome is associated with an early death. There are two types of the syndrome. Type 1 is not recognizable at birth. Instead, symptoms become evident after the child's first birthday. Type 1 results in death during the teenage years. Type 2 is recognizable at birth. Life expectancy for Type 2 is between six and seven years of age. The cause of death is often due to premature hardening of the arteries.