Xeroderma pigmentosum-Cockayne syndrome (XP-CS) occurs when an individual also has xeroderma pigmentosum, another DNA repair disease. Some symptoms of each disease are expressed. For instance, freckling and pigment abnormalities characteristic of XP are present. The neurological disorder, spasticity, and underdevelopment of sexual organs characteristic of CS are seen. However, hypomyelination and the facial features of typical CS patients are not present. Causes
If hyperoxia or excess oxygen occurs in the body, the cellular metabolism produces several highly reactive forms of oxygen called free radicals. This can cause oxidative damage to cellular components including the DNA. In normal cells, our body repairs the damaged sections. In the case of this disease, due to subtle defects in transcription, childrens genetic machinery for synthesizing proteins needed by the body does not operate at normal capacity. That is, scientists believed that these childrens genetic machinery for synthesizing proteins needed by the body does not operate at normal capacity. Over time, went this theory, results in developmental failure and death. Every minute, the body pumps 10 to 20 liters of oxygen through the blood, carrying it to billions of cells in our bodies. In its normal molecular form, oxygen is harmless. However, cellular metabolism involving oxygen can generate several highly reactive free radicals. These free radicals can cause oxidative damage to cellular components including the DNA. In an average human cell, several thousand lesions occur in the DNA every day. Many of these lesions result from oxidative damage.
The average lifespan for children with type B is up to 7 years of age. These symptoms are seen in CS type 2 children. Cockayne syndrome type C (CSC) appears later in childhood with milder symptoms than the other types and a slower progression of the disorder. People with this type of Cockayne syndrome live into adulthood, with an average lifespan of 40 to 50 years. These symptoms are seen in CS type 3. Epidemiology
Cockayne syndrome is rare worldwide. No racial predilection is reported for Cockayne syndrome. No sexual predilection is described for Cockayne syndrome; the male-to-female ratio is equal. Cockayne syndrome I (CS-A) manifests in childhood. Cockayne syndrome II (CS-B) manifests at birth or in infancy, and it has a worse prognosis. Recent research
The recent research on Jan 2018 mentions different CS features that are seen globally with similarities and differences:
CS has an incidence of 1 in 250,000 live births, and a prevalence of approximately 1 per 2.5 million, which is remarkably consistent across various regions globally:

See also
Accelerated aging disease
Biogerontology
Degenerative disease
Genetic disorder
CAMFAK syndrome — thought to be a form (or subset) of Cockayne syndrome

References
External links
This article incorporates some public domain text from The U.S. National Library of Medicine