Cockayne syndrome

Overview
Cockayne syndrome (or "Weber-Cockayne syndrome", or "Neill-Dingwall Syndrome") is a rare, autosomal recessive disorder characterized by growth failure, impaired development of the nervous system, abnormal sensitivity to sunlight (photosensitivity), and premature aging. Hearing loss and eye abnormalities (pigmentary retinopathy) are other common features, but problems with any or all of the internal organs are possible. It is named after English physician Edward Alfred Cockayne (1880-1956).

Forms of Cockayne syndrome

 * CS Type I, or the “classic form”, is characterized by normal fetal growth with the onset of abnormalities in the first two years of life. Impairment of vision, hearing, and the central and peripheral nervous system progressively degenerate until death in the first or second decade of life.
 * CS Type II, otherwise known as connatal CS, involves very little neurological development after birth. Death usually occurs by age 7.
 * CS Type III is rare and is characterized by late onset. It is milder than Type I and Type II.
 * Xeroderma-pigmentosum-Cockayne syndrome (XP-CS) occurs when an individual also suffers from Xeroderma pigmentosum, another DNA repair disease. Some symptoms of each disease are expressed.

The condition is also classified genetically as follows:
 * (TYPE A)
 * (TYPE B)
 * (TYPE C)

Causes
Mutations in the ERCC6 and ERCC8 genes cause Cockayne syndrome. The proteins made by the ERCC8 and ERCC6 genes are involved in repairing damaged DNA by the transcription-coupled repair mechanism, particularly the DNA in active genes. If either tr the ERCC6 gene is altered, DNA damage is not repaired. As this damage accumulates, it can lead to malfunctioning cells or cell death, and the signs and symptoms of Cockayne syndrome.

Physical appearance
Small head size, short stature, sunken eyes, "aged" look.