Werner syndrome (WS) or Werners syndrome, also known as "adult progeria", is a rare, autosomal recessive disorder which is characterized by the appearance of premature aging.Werner syndrome is named after the German scientist Otto Werner. He identified the syndrome in four siblings observed with premature aging, which he explored as the subject of his dissertation of 1904.It has a global incidence rate of less than 1 in 100,000 live births (although incidence in Japan and Sardinia is higher, affecting 1 in 20,000–40,000 and 1 in 50,000, respectively). 1,300 cases had been reported as of 2006. Affected individuals typically grow and develop normally until puberty; the mean age of diagnosis is twenty-four, often realized when the adolescent growth spurt is not observed. The youngest person diagnosed was six years old. The median and mean ages of death are 47–48 and 54 years, respectively. The main causes of death are cardiovascular disease and cancer. Presentation
Werner syndrome patients exhibit growth retardation, short stature, premature graying of hair, alopecia (hair loss), wrinkling, prematurely aged faces with beaked noses, skin atrophy (wasting away) with scleroderma-like lesions, lipodystrophy (loss of fat tissues), abnormal fat deposition leading to thin legs and arms, and severe ulcerations around the Achilles tendon and malleoli (around ankles).
Mutations may also lead to the truncation (shortening) of the WRNp protein, leading to the loss of its nuclear localization signal sequence, thus it is no longer transported into the nucleus where it interacts with the DNA. This leads to a reduction in DNA repair. Furthermore, mutated proteins are more likely to be degraded than normal WRNp. Apart from causing defects in DNA repair, its aberrant association with p53 down-regulates the function of p53, leading to a reduction in p53-dependent apoptosis and increasing the survival of these dysfunctional cells. Cells of affected individuals also have reduced lifespan in culture, have more chromosome breaks and translocations and have extensive deletions.Patients with Werner syndrome lose the RecQ helicase activity in the WRN protein because of the loss of its C-terminus region, but the mechanism by which this happens is unclear. The loss of the helicase activity can have far-reaching consequences in terms of cell stability and mutation. One instance of these consequences involves telomeres. It is thought that the WRN helicase activity is important not only for DNA repair and recombination, but also for maintaining telomere length and stability. Thus, WRN helicase is important for preventing catastrophic telomere loss during DNA replication. In a normal cell, the telomeres (the ends of chromosomes) undergo repeated shortening during the cell cycle, which can prevent the cell from dividing and multiplying.