Lesch-Nyhan syndrome pathophysiology
|
Lesch-Nyhan syndrome Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Lesch-Nyhan syndrome pathophysiology On the Web |
|
American Roentgen Ray Society Images of Lesch-Nyhan syndrome pathophysiology |
|
Risk calculators and risk factors for Lesch-Nyhan syndrome pathophysiology |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aarti Narayan, M.B.B.S [2]
Overview
It is an inborn error in purine metabolism resulting in deficiency of HGPRT enzyme, resulting in increased conversion of glycine to uric acid with excessive purine synthesis and hyperurecemia.
Pathophysiology
- Patients have severe mental and physical problems throughout life. The lack of HGPRT causes a build-up of uric acid in all body fluids, and leads to problems such as severe gout, poor muscle control, and moderate mental retardation, which appear in the first year of life.
- A striking feature of LNS is self-mutilating behaviors, characterized by lip and finger biting, that begin in the second year of life.
- Abnormally high uric acid levels can cause sodium urate crystals to form in the joints, kidneys, central nervous system and other tissues of the body, leading to gout-like swelling in the joints and severe kidney problems.
- Neurological symptoms include facial grimacing, involuntary writhing, and repetitive movements of the arms and legs similar to those seen in Huntington's disease. The direct cause of the neurological abnormalities remains unknown.
- Because a lack of HGPRT causes the body to poorly utilize vitamin B12, some boys may develop a rare disorder called megaloblastic anemia.
- The symptoms caused by the buildup of uric acid (arthritis and renal symptoms) respond well to treatment with drugs such as allopurinol that reduce the levels of uric acid in the blood.
- The mental deficits and self-mutilating behavior do not respond to treatment. There is no cure, but many patients live to adulthood.
Genetics
LNS is an X-linked recessive disease. The gene is carried by the mother and passed on to her son. LNS is present at birth in baby boys.