Tyrosinemia Type-I
An autosomal recessive disease. The incidence varies form 1:10000 to 1:800 in different geographic areas. Tyrosinemia is diagnosed by demonstrating reduced activity of a vital enzyme FAH (Fumary1 Acetoace hydrogenase) in the blood. Early neonatal screening is essential to diagnose this condition. Lethal liver failure and neurological crises can develop in affected individuals. No FAH activity is discovered in patients with acute failure and up to 20% activity is found in infants with chronic liver failure. Infants usually present with bleeding diathesis due to onset of acute liver failure. The chronic form usually presents after first year. The liver becomes enlarged, coarsely nodular and cirrhotic. At two years of age they have a very high chance of developing liver cell cancer. The neurological consequences could be fatal and include profound weakness and paralysis and respiratory paralysis and respiratory paralysis usually leads to death. Infants can also develop acute/chronic kidney failure.
Treatment is aimed at dietary modification by avoiding Tyrosine, phenylalanine and methionine. A chemical NTBC has been tried to reduce liver injury by toxic metabolites. Dietary modification offers no protection against progression of liver disease and development of cancer. Good outcomes (up to 80%) have been reported after liver transplant for both acute and chronic forms of Tyrosinemia. However complete kidney recovery may not be achieved by liver transplantation.
No comments:
Post a Comment