Cockayne syndrome

Cockayne syndrome is a rare disorder characterized by short stature and an appearance of premature aging. Features of this disorder include a failure to gain weight and grow at the expected rate (failure to thrive), small head size (microcephaly), impaired development of the nervous system, and an abnormal sensitivity to sunlight (photosensitivity). Other possible signs and symptoms include hearing loss, eye abnormalities, severe tooth decay, and problems with internal organs.

Cockayne syndrome can be divided into subtypes, which are distinguished by the severity and age of onset of symptoms. Classical, or type I, Cockayne syndrome is characterized by an onset of symptoms in early childhood (usually after age 1 year). Cockayne syndrome, type II is an early-onset form with severe symptoms that are apparent at birth (congenital). Type II Cockayne syndrome is sometimes called cerebro-oculo-facio-skeletal (COFS) syndrome or Pena-Shokeir syndrome type II. A few cases of type III Cockayne syndrome, which has mild symptoms and onset in late childhood, have been reported. Some individuals have combined features of Cockayne syndrome and another photosensitivity disorder called xeroderma pigmentosum, which is characterized by a wide range of skin changes, from mild freckling to skin cancer.

The prevalence of Cockayne syndrome is unknown. It probably occurs in fewer than 1 in 100,000 individuals.

Mutations in the ERCC6 and ERCC8 genes cause Cockayne syndrome.

The ERCC6 and ERCC8 genes provide instructions for making proteins that are involved in repairing damaged DNA. If either gene is altered, DNA damage is not rapidly repaired. As a result, damaged DNA accumulates, which probably leads to impaired cell functions and eventually, cell death. Increased cell death likely contributes to features of Cockayne syndrome such as growth failure and premature aging.

Read more about the ERCC6 and ERCC8 genes.

This condition is 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.