Cockayne syndrome is a rare autosomal recessive

Recessive

In genetics, the term "recessive gene" refers to an allele that causes a phenotype that is only seen in a homozygous genotype and never in a heterozygous genotype. Every person has two copies of every gene on autosomal chromosomes, one from mother and one from father...

, congenital disorder

Congenital disorder

A congenital disorder, or congenital disease, is a condition existing at birth and often before birth, or that develops during the first month of life , regardless of causation...

 characterized by growth failure, impaired development of the nervous system

Nervous system

The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...

, abnormal sensitivity to sunlight

Sunlight

Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...

 (photosensitivity

Photosensitivity

Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light.- Human medicine :Sensitivity of the skin to a light source can take various forms. People with particular skin types are more sensitive to sunburn...

), and premature aging. Hearing loss and eye

Human eye

The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...

 abnormalities (pigmentary retinopathy) are other common features, but problems with any or all of the internal organs are possible. It is associated with a group of disorders called leukodystrophies. The underlying disorder is a defect in a DNA repair mechanism.

It is named after English physician Edward Alfred Cockayne

Edward Alfred Cockayne

Edward Alfred Cockayne was an English physician specializing in pediatrics. He spent most of his medical career at Great Ormond Street Hospital for Sick Children in London....

 (1880–1956). Neill-Dingwall syndrome was named after Mary M. Dingwall and Catherine A. Neill.

Forms of Cockayne syndrome (CS)

• CS Type I, 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 systems 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 seven. This specific type has also been designated as cerebro-oculo-facio-skeletal (COFS) syndrome. COFS syndrome can be further subdivided into several conditions (COFS types 1, 2, 3 (associated with xeroderma pigmentosum
  Xeroderma pigmentosum
  Xeroderma pigmentosum, or XP, is an autosomal recessive genetic disorder of DNA repair in which the ability to repair damage caused by ultraviolet light is deficient. In extreme cases, all exposure to sunlight must be forbidden, no matter how small. Multiple basal cell carcinomas and other skin...
  
  ) and 4).
• CS Type III, characterized by late onset, is rare and milder than Types I and 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.

Genetics

Cockayne syndrome is classified gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

tically as follows:

Type	OMIM	Gene
A		ERCC8
B		ERCC6 ERCC6 DNA excision repair protein ERCC-6 is a protein that in humans is encoded by the ERCC6 gene.-External links:*...
C		none known

Mutations in the ERCC6

ERCC6

DNA excision repair protein ERCC-6 is a protein that in humans is encoded by the ERCC6 gene.-External links:*...

 and ERCC8 genes are the cause of Cockayne syndrome. The protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s made by these genes are involved in repairing damaged

DNA repair

DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as UV light and radiation can cause DNA damage, resulting in as many as 1...

 DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 via the transcription-coupled repair

Transcription-coupled repair

Transcription-coupled repair is a DNA repair mechanism which operates in tandem with transcription. The activity of TCR has been known for 20 years, but its mechanism of action is an area of current research...

 mechanism, particularly the DNA in active genes. If either the ERCC6 or the ERCC8 gene is altered, DNA damage is not repaired. As this damage accumulates, it can lead to malfunctioning cells or cell death.

Mutations in the ERCC6 gene mutation makes up ~70% of cases.

Physical appearance

Persons with this syndrome have smaller than normal head sizes, are of short stature, their eyes appear sunken, and they have an "aged" look.

See also

• Accelerated aging disease
  Accelerated aging disease
  A DNA repair-deficiency disorder is a medical condition due to reduced functionality of DNA repair.DNA repair defects are seen in nearly all of the diseases described as accelerated aging disease, in which various tissues, organs or systems of the human body age prematurely...
  
  
• Biogerontology
• Degenerative disease
  Degenerative disease
  A degenerative disease, also called neurodegenerative disease, is a disease in which the function or structure of the affected tissues or organs will progressively deteriorate over time, whether due to normal bodily wear or lifestyle choices such as exercise or eating habits...
  
  
• Genetic disorder
  Genetic disorder
  A genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions....
  
  
• CAMFAK syndrome
  CAMFAK syndrome
  CAMFAK syndrome is an acronym used to describe a rare inherited neurologic disease, characterized by peripheral and central demyelination of nerves, similar to that seen in Cockayne syndrome...
  
  — thought to be a form (or subset) of Cockayne syndrome

External links

• Share and Care Cockayne Syndrome Network
• This article incorporates some public domain text from The U.S. National Library of Medicine
• 'Amy and Friends' — a friendly charity based in the UK supporting children with Cockayne Syndome