Liver transplantation in a 23-year-old tyrosinaemia patient: effects on the renal tubular dysfunction

Orthotopic liver transplantation was performed on a 23-year-old female with hereditary tyrosinaemia. The disorder was diagnosed at 7 years of age due to severe rickets, and the patient was treated with a diet restricted in phenylalanine and tyrosine. Nineteen months before the transplantation she had an acute episode of diffuse gastrointestinal bleeding due to portal hypertension. Three subsequent bleeding episodes with accompanying ascites and signs of encephalopathy were considered life-threatening. Nine months after the liver transplantation the patient is well, but serum transaminases are slightly elevated. Without dietary restrictions serum tyrosine and inorganic phosphate are normalized, no succinylacetone can be detected in serum, and urinary excretion of p-hydroxyphenyllactate and p-hydroxyphenylpyruvate is normal. Excretion of amino acids, glucose and beta 2-microglobulin decreased significantly after the transplantation but is still elevated. The succinylacetone concentration in urine is about 20% of the preoperative level. After an oral tyrosine load, succinylacetone excretion increased sevenfold but no deterioration of the renal tubular function was observed and no tyrosine metabolites were detectable in serum. The findings indicate that the defective tyrosine metabolism occurs in the kidneys, but does not produce tubular dysfunction. The residual tubular dysfunction of the patient is probably due to irreversible damage of the tubular epithelium.