Genetic Causes of Intellectual Disabilities: Cockayne Syndrome Disease
Cockayne syndrome is named after Edward Alfred Cockayne, a physician who discovered the condition in 1946. This rare genetic disorder involves defective CSA and CSB genes on chromosome 5. CSA and CSB genes are proteins that are key components used by the body for DNA repair.
The CSB and CSA proteins help DNA repair itself. The lack of these proteins in affected individuals manifests as premature aging. The aging process is significantly accelerated with exposure to sunlight, specifically UV radiation. The purpose of the CSB protein is to interface and replicate damaged DNA. Cockayne condition differs from other DNA repair disorders in that cancer is not associated with the syndrome.
Physical features of Cockayne syndrome include a generally short physique accompanied by disproportionately long arms and legs. Hands and feet tend to be quite large, while the head is unusually small. Eyes are often sunken and the ears are usually deformed. The disorder is associated with dwarfism.
Individuals with Cockayne syndrome tend to have visual problems stemming from retinal degeneration or optic nerve atrophy. They often have difficulty closing their eyelids completely and as a result, suffer from dryness of the cornea. Hearing problems are common, resulting from ear deformations and a progressive deterioration of neurons associated with hearing (as occurs during regular aging).
Cockayne syndrome is, unfortunately, 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. This form of the syndrome results in death during the teenage years. Type 2 is recognizable at birth. Life expectancy for Type 2 Cockayne syndrome is between six and seven years of age. The cause of death is often due to early atherosclerosis (hardening of the arteries).