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Tuesday, July 3, 2012

Health Talk: Progeria





Progeria (also known as "Hutchinson–Gilford Progeria Syndrome", "Hutchinson–Gilford syndrome",and "Progeria syndrome") is an extremely rare genetic disease wherein symptoms resembling aspects of aging are manifested at an early age. The word progeria comes from the Greek words "pro"  meaning "before", and "géras", meaning "old age". 

The disorder has very low incidences and occurs in an estimated 1 per 8 million live births. Those born with progeria typically live to their mid teens and early twenties. It is a genetic condition that occurs as a new mutation, and is rarely inherited. Although the term progeria applies strictly speaking to all diseases characterized by premature aging symptoms, and is often used as such, it is often applied specifically in reference to Hutchinson-Gilford Progeria Syndrome (HGPS).


Signs and Symptoms
Children with progeria usually develop the first symptoms during infancy. The earliest symptoms include failure to thrive and a localized scleroderma-like skin condition. As a child ages past infancy, additional conditions usually become apparent around 18–24 months. Limited growth, full-body alopecia, and a distinctive appearance (small face and jaw, pinched nose) are all characteristics of progeria. Signs and symptoms of this progressive disease tend to get worse as the child ages. 

Later, the condition causes wrinkled skin, atherosclerosis, kidney failure, loss of eyesight, hair loss, and cardiovascular problems. Scleroderma, a hardening and tightening of the skin on trunk and extremities of the body, is prevalent. People diagnosed with this disorder usually have small, fragile bodies, like those of elderly people. The face is usually wrinkled, with a larger head in relation to the body, a narrow face and a beak nose. Prominent scalp veins are noticeable (made more obvious by hair loss), as well as prominent eyes. Musculoskeletal degeneration causes loss of body fat and muscle, stiff joints, hip dislocations, and other symptoms generally absent in the non-elderly population. Individuals usually retain normal mental and motor development.
  • Growth failure during the first year of life
  • Narrow, shrunken or wrinkled face
  • Baldness
  • Loss of eyebrows and eyelashes
  • Short stature
  • Large head for size of face (macrocephaly)
  • Open soft spot (fontanelle)
  • Small jaw (micrognathia)
  • Dry, scaly, thin skin
  • Limited range of motion
  • Teeth - delayed or absent formation

Cause
Steps in normal cellSteps in cell with progeria
The gene LMNA encodes a protein called prelamin A.The gene LMNA encodes a protein called prelamin A.
Prelamin A has a farnesyl group attached to its end.Prelamin A has a farnesyl group attached to its end.
Farnesyl group is removed from prelamin A.Farnesyl group remains attached to prelamin A.
Normal form is called prelamin A.Abnormal form of prelamin A is called progerin.
Prelamin A is not anchored to the nuclear rim.Progerin is anchored to the nuclear rim.
Normal state of the nucleus.Abnormally shaped nucleus.


Treatment
No treatments have been proven effective. Most treatment focuses on reducing complications (such as cardiovascular disease) with heart bypass surgery or low-dose aspirin. Children may also benefit from a high-calorie diet.


Prognosis
As there is no known cure, few people with progeria exceed 13 years of age. At least 90% of patients die from complications of atherosclerosis, such as heart attack or stroke.
Mental development is not adversely affected; in fact, intelligence tends to be above average. With respect to the features of aging that progeria appears to manifest, the development of symptoms is comparable to aging at a rate eight to ten times faster than normal. With respect to features of aging that progeria does not exhibit, patients show no neurodegeneration or cancer predisposition. They also do not develop the so-called "wear and tear" conditions commonly associated with aging, such as cataracts (caused by UV exposure) and osteoarthritis (caused by mechanical wear).
Although there may not be any successful treatments for progeria itself, there are treatments for the problems it causes, such as arthritic, respiratory, and cardiovascular problems.






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