Tyrosinemia: Causes, Symptoms, Diagnosis, Treatment

Tyrosinemia is a metabolic disorder in which the body is not able to effectively break down an amino acid called Tyrosine. Increased concentration of tyrosine in blood affects the liver and kidneys. In this article, we will discuss in detail about the various causes, symptoms, and treatment for Tyrosinemia.

Tyrosinemia is a form of metabolic error, which is congenital in nature in relation to acute liver dysfunction during infancy. In Tyrosinemia, the body is unable to break down amino acid effectively resulting in severe kidney and liver dysfunction. Tyrosinemia is inherited in an autosomal recessive way meaning that to have the disease the child must inherit two defective genes, one from each parent. The ratio of infected versus non-infected individuals is 1:100,000. There are three forms of Tyrosinemia with each form having its own set of symptoms and is caused by deficiency of different enzymes. These three forms are:

• Type I Tyrosinemia¹
• Type II Tyrosinemia
• Type III Tyrosinemia

Tyrosine is an amino acid found in the proteins, which is basically metabolized in the liver. Tyrosinemia is caused as a result of the absence of enzyme Fumarylacetoacetate Hydrolase. This enzyme is extremely vital for tyrosine metabolism. If the enzyme Fumarylacetoacetate Hydrolase is absent, this often leads to accumulation of toxic metabolic products in different body tissues ultimately resulting in gradual damage to liver and kidneys.

When it comes to symptoms of Tyrosinemia, they basically fall into two major forms, acute and chronic.

• Acute Phase-
  • Infants- poor weight gain
  • Enlarged liver (Hepatomegaly)
  • Enlarged spleen (Splenomegaly)
  • Swelling of the lower leg
  • Liver failure- Despite aggressive therapy in such cases, death as a result of liver failure occurs by the age of nine months unless a liver transplantation is done.¹
• Chronic Phase-¹
  • Liver Effects-
    • Hepatomegaly,
    • Cirrhosis,
    • Liver failure
    • Jaundice
  • Splenomegaly- Enlarged spleen
  • Cardiomyopathy- Results in cardiac failure ²
  • Seizures
  • Kidney Effects-³
    • Tubulopathy,
    • Nephromegaly
    • Fanconi syndrome,
    • Kidney failure
  • Failure to thrive.
  • Ascites

  Diagnosis of Tyrosinemia

  Blood Examination-

  • Liver Function Test- Abnormal
    • AST (aspartate transaminase) enzyme- elevated
    • ALT (alanine transaminase) enzyme- elevated
    • Serum Bilirubin- elevated
  • BUN and Creatinine- elevated
  • Serum Albumin Level- low

  Ultrasound Examination-

  • Cardiomegaly- enlarged heart,
  • Hepatomegaly- enlarged and nodular liver ⁴
  • Splenomegaly- enlarged spleen

  CT Scan and/or Magnetic Resonance Imaging (MRI)

  

  • Kidney- abnormal kidney size and shape.
  • Cardiomegaly- enlarged heart,
  • Hepatomegaly- enlarged and nodular liver,⁴
  • Splenomegaly– enlarged spleen.

  Treatment For Tyrosinemia

  Dietary Modification-

  • Dietary modification is extremely vital for treatment of Tyrosinemia.
  • Foods rich in Tyrosine like meat, dairy products, and other food products rich in protein like nuts need to be avoided.
  • Control of diet and providing adequate nutrition may not cure Tyrosinemia but goes a long way in controlling the metabolic dysfunction and promotes normal growth and development.
  • Diet should contain low concentration of phenylalanine and tyrosine as that helps to prolong severe liver damage.³

  Nitisinone Treatment

  Nitisinone has also been shown to be effective.⁴

  Liver Transplant

  Liver transplant for advanced cases of Tyrosinemia.⁴

  References:

  1. Tyrosinemia type I: clinical and biochemical analysis of patients in Mexico.
     Fernández-Lainez C1, Ibarra-González I2, Belmont-Martínez L1, Monroy-Santoyo S1, Guillén-López S1, Vela-Amieva M1.
     Ann Hepatol. 2014 Mar-Apr;13(2):265-72.
  2. Tyrosinemia type 1: a rare and forgotten cause of reversible hypertrophic cardiomyopathy in infancy.
     Mohamed S1, Kambal MA, Al Jurayyan NA, Al-Nemri A, Babiker A, Hasanato R, Al-Jarallah AS.
     BMC Res Notes. 2013 Sep 9;6:362.
  3. Hepatorenal tyrosinemia.
     Kitagawa T.
     Proc Jpn Acad Ser B Phys Biol Sci. 2012;88(5):192-200.
  4. Clinical and para clinical findings in the children with tyrosinemia referring for liver transplantation.
     Dehghani SM1, Haghighat M2, Imanieh MH1, Karamnejad H2, Malekpour A2.
     Int J Prev Med. 2013 Dec;4(12):1380-5.