Cockayne syndrome type II, also considered the severe form of Cockayne syndrome, is a rare genetic disorder that causes early (premature) aging. Affected individuals have delayed growth at birth and poor development that is first noticed in infancy. 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, and changes to the brain that can be seen on imaging (brain MRIs). Affected babies can have eye abnormalities, such as a cloudy lens (cataract), and an abnormal curve to the spine (scoliosis) at birth. Cockayne syndrome type II is a very serious condition and, sadly, most affected children do not live past age seven.
Cockayne syndrome type II 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 II. 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 II.
Cockayne syndrome type II is considered in children who have growth problems noticed at birth along with 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. There is no cure for Cockayne syndrome type II. If your child has been diagnosed with Cockayne syndrome type II, talk to their doctor about all treatment options. Support groups can provide more information.