Tyrosinemia type 1: a case report

Background. Hereditary Tyrosinemia Type 1 (HT1) is an orphan disease belonging to the group of amino acid metabolism disorders, with an autosomal recessive pattern of inheritance. It is caused by a mutation in the FAH gene, which encodes the enzyme fumarylacetoacetate hydrolase. The clinical presentation is polymorphic. Diagnosis is based on the detection of specific metabolites in biological samples and molecular genetic testing. Early diagnosis determines the effectiveness of therapy and the prognosis of the disease.

Clinical case description. We present a clinical case of early detection of HT1 in a female newborn through expanded neonatal screening. The clinical picture was characterized by hepatomegaly, coagulopathy, and specific biomarkers, including elevated levels of succinylacetone in the blood. This finding served as the basis for immediate initiation of nitisinone therapy and an individually calculated low protein diet supplemented with a specialized amino acid mixture. Molecular genetic testing confirmed the diagnosis: a previously described pathogenic nucleotide sequence variant, chr15:80181069G>C in the FAH gene in a homo/hemizygous state, was identified. This variant leads to a missense substitution c.1090G>C, p.(Glu364Gln). During the follow up period, the patient has shown a favorable course of the disease.

Conclusion. Early diagnosis of HT1 based on specific succinylacetone screening and timely initiation of pathogenetic therapy combined with dietary management ensure a favorable prognosis for the disease.

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