Werner syndrome...펌

Werner syndrome

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Werner syndrome
Classification & external resources

ICD-9	259.8
OMIM	277700
DiseasesDB	14096
MeSH	C16.320.925

Werner syndrome is a very rare, autosomal recessive disorder; its most recognizable characteristic is premature aging. Werner's syndrome more closely resembles "accelerated aging" than any other "segmental progeria." For this reason, Werner syndrome is often referred to as a progeroid syndrome, as it partly mimics the symptoms of Progeria. The defect is on a gene that codes DNA helicase and it is located on the short arm of the 8th chromosome. As a result DNA replication is impaired. This condition is inherited in an autosomal recessive pattern.

Contents [hide] 1 Symptoms 2 Genetics 3 History 4 See also 5 External links

[edit] Symptoms

Individuals with this syndrome typically develop normally until they reach puberty. Following puberty they age rapidly, so that by age 40 they often appear several decades older. The age of onset of Werner syndrome is variable, but an early sign is the lack of a teenage growth spurt, which results in short stature. Other signs and symptoms appear when affected individuals are in their twenties or thirties and include loss and graying of hair, hoarseness of the voice, thickening of the skin, and cloudy lenses (cataracts) in both eyes. Overall, people affected by Werner syndrome have thin arms and legs and a thick torso. Affected individuals typically have a characteristic facial appearance described as "bird-like" by the time they reach their thirties. Patients with Werner syndrome also exhibit genomic instability, hypogonadism, and various age-associated disorders; these include cancer, heart disease, atherosclerosis, diabetes mellitus, and cataracts. However, not all characteristics of old-age are present in Werner patients; for instance, senility is not seen in individuals with Werner syndrome. People affected by Werner syndrome usually do not live past their late forties or early fifties, often dying from the results of cancer or heart disease.

[edit] Genetics

Werner syndrome is inherited in an autosomal recessive fashion.

In 1997 the gene responsible for Werner syndrome was identified (and named WRN) and found to be a member of the RecQ family of helicases. Other members of this family include the genes responsible for Bloom syndrome (BLM gene), and a subset of Rothmund-Thomson (RECQ4 gene) patients. The Werner protein is thought to perform several tasks in the cell, including the maintenance and repair of DNA. It also assists in making copies of DNA in preparation for cell division. Mutations in the WRN gene often lead to the production of an abnormally short Werner protein. Some research suggests that this shortened protein is not sent to the nucleus, where it normally interacts with DNA. Evidence also suggests that the altered protein is broken down quickly in the cell, leading to a loss of Werner protein function

Research into the biological role of the WRN protein is ongoing, but current evidence strongly suggests a role for WRN in the resolution of Holliday junctions. Roles in non-homologous end joining (NHEJ) and the restoration of stalled replication forks have also been suggested.

The trait for Werner's Syndrome is auto-recessive.[1]

[edit] History