Cockayne syndrome type 1, also called classic Cockayne syndrome, is a rare genetic disorder that causes early (premature) aging. Affected individuals have normal growth before birth (prenatal), but have delayed growth and development in the first two years of life. Symptoms may include height that is below average (short stature), sunlight sensitivity (photosensitivity), difficulty gaining weight (failure to thrive), small head size (microcephaly), hearing loss, eye and bone abnormalities, and changes to the brain that can be seen on imaging (brain MRIs). Even a small amount of sunlight can cause severe sunburn in a person with Cockayne syndrome.
Cockayne syndrome type 1 is caused by changes (mutations) in either the ERCC6 or ERCC8 gene. These genes act as instructions for the body to make proteins that are important for DNA repair. DNA damage typically occurs from exposure to the sun, toxic chemicals, or radiation. Normally, the body is able to repair this damage before it causes health issues. However, individuals with this condition cannot repair the damage fast enough, which causes cells to die off early and leads to the premature aging seen in Cockayne syndrome type 1. This condition is inherited in an autosomal recessive way, which means a mutation in both copies of the gene a child has is needed to cause Cockayne syndrome type 1.
Cockayne syndrome type 1 is considered in children who have failure to thrive, short stature, or other features of premature aging. The diagnosis can be confirmed with a test that looks for DNA repair problems on a piece of skin (biopsy) or with genetic testing. Although there is no cure for Cockayne syndrome type 1, there are options to help decrease the symptoms, including the use of strong sunscreen and avoiding sunlight. If your child has been diagnosed with Cockayne syndrome type 1, talk to their doctor about all treatment options. Support groups can provide more information.