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Transcript of Cockayne Syndrome
What is it?
There are four different types of CS. CS is a rare form of dwarfism. It is an inherited disorder whose diagnosis depends on the presence of three signs (1) growth retardation, i.e. short stature, (2) abnormal sensitivity to light (photosensitivity), and (3) prematurely aged appearance (progeria). In the classical form of Cockayne Syndrome (CS type I) the symptoms are progressive and typically become apparent after the age of one year. An early onset or congenital form of Cockayne Syndrome (CS type II) is apparent at birth (congenital). There is a third form, known as Cockayne Syndrome Type III (CS type III), that presents later in the child's development and is generally a milder form of the disease. A fourth form; now recognized as Xeroderma pigmentosa-Cockayne syndrome (XP-CS), combines features of both of these disorders.
Cockayne syndrome is a genetically heterogeneous disorder, and certain types show some overlap with certain forms of xeroderma pigmentosum (XP), another disorder caused by defective DNA repair. See also Cockayne syndrome B (133540), caused by mutation in the ERCC6 gene (609413) on chromosome 10q11; XPG/CS (see 278780), caused by mutation in the ERCC5 gene (133530) on chromosome 13q33; XPB/CS (see 610651), caused by mutation in the ERCC3 gene (133510) on chromosome 2q21; and XPF/CS (see 278760), caused by mutation in the ERCC4 gene (133520) on chromosome 16p13.
There are 53 symptoms for CS (not all are listed here):
Severe growth deficiency
Delayed teeth eruption
Mutations in the ERCC6 (CSB) or ERCC8 (CSA) genes cause Cockayne syndrome. The ERCC6 and ERCC8 genes provide instructions for making two proteins, called CSB and CSA, which are involved in repairing DNA. If either gene is altered, DNA damage is not as 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.
What genes are related?
In a "normal" pathway, even with some DNA damage, the dysfunctional DNA is able to be removed. This allows for proper transcription to happen. The result of this is life with cells. Cancer does not occur in this pathway.
The problem that causes CS is improper nucleotide excision. The damaged DNA is not cut out and replaced, therefore defective DNA is copied. This causes problems in transcription that leads to defective mRNA & RNA's being produced. In some causes apoptosis occurs and in others abnormal cell division occurs.
By: Jobie & Ian
CSA & CSB
Recent findings suggest that CSA and CSB proteins have different roles in TC-NER. The CSA protein forms an ubiquitin ligase complex consisting of DDB1, cullin4A, Roc1 and the COP9 signalosome, while the CSB protein is a member of the SWI2/SNF2 family and has DNA-dependent ATPase and ATP-dependent chromatin remodeling activities. It has been shown that xeroderma pigmentosum (XP) patients with CS (XP/CS) have defects in transcription as well as in NER. It is suggested that CS is a disorder with DNA repair/transcription-deficiencies.
These images show cerebral atrophy & thinning of brain stem and soft calcification of basal ganglia.
No specific treatment currently exists for CS. Patients should be treated according to the symptoms they have. Physical, occupational, speech, vision, and hearing therapy are most often beneficial.
A person with this disease will rarely live to be adults. The common life span is 12.5 years.
CS is an extremely rare disease. Less than 1 in every 100,000 people inherit this disease.
There is currently much research being done for CS. Research centers in Germany & America are doing extensive research. Items such as bio fluorescent lab worms are being used. The researches are trying to figure out exactly why the RNA is transcribed incorrectly. Not many drugs are being used because they believe that they can have a negative affect on the patient's enzymes.