Hereditary tyrosinemia type I (HT-I) is an autosomal recessive inborn error of tyrosine metabolism, caused by
mutation(s) in the gene encoding for fumarylacetoacetate hydrolase (FAH) enzyme. The authors report a Thai boy who
presented at two months of age with liver failure. HT-I was diagnosed based on the presence of succinylacetone in urine and
homozygous R237X mutations of FAH gene. He was started on tyrosine and phenylalanine restricted diet immediately. Due to
a limitation of 2-(2-nitro-4-trifluoromethyl benzoyl)-1, 3-cyclohexanedione (NTBC) therapy in Thailand, it was commenced at
eight months old and used as a bridging therapy before liver transplantation. He had a good response to NTBC therapy with
an improvement in liver chemistries and synthetic functions. Subsequently, living donor liver transplantation (LDLT) was
performed at 15 months old. Long-term follow-up for 6.3 years following LDLT revealed normal growth, good school
performance, normal liver, renal tubular, and glomerular functions, and without urinary excretion of succinylacetone.
Conclusion: Liver transplantation is a promising treatment for patients with HT-I when NTBC is unavailable, resulting in a
good long-term outcome.

Keywords: Tyrosinemia, Hereditary tyrosinemia type I, Cholestatic jaundice, Cirrhosis, Liver failure, Liver transplantation,
Living donor liver transplantation