Cockayne Syndrome is a progressive infantile dystrophy syndrome. The most important symptoms include dwarfism, neurological deficits and mental retardation. Further symptoms include photosensitivity, visual and high temperatures and premature aging. Also, certain characteristic facial features can be observed. These include microcephaly, large ears, sunken eyes, and a narrow nose.
The time of onset and severity vary, and there are three types to be distinguished. If the most common Type I CS is present, the symptoms begin as early as the first year of life. Type II describes patients with even more early onset and severe symptoms. In type III, the symptoms occur later and are milder.
The cause of the cutaneous symptoms of Cockayne syndrome is a defect in nucleotide excision repair (NER), more specifically in the transcriptional-coupled DNA repair. This defect has the consequence that UV-induced DNA lesions in actively transcribed genes are not properly repaired, nor can be corrected. As the cause of non-cutaneous symptoms, further defects of the oxidation repair and basal transcription systems are suspected.
The defects are caused by mutations in the genes ERCC6 / CSB (10q11) and ERCC8 / CSA (5q12.1). Inheritance of the mutation is autosomal recessive.
The prognosis of CS patients is usually not very good. Especially sufferers of type I and II have no high life expectancy.