Tyrosinemia Type 1: A Case Prior to Newborn Screening and the Importance of Early Treatment

Abstract

Abstract

Introduction: Tyrosinemia type 1 (TYR1) is a severe hereditary metabolic disorder caused by a deficiency of the enzyme fumarylacetoacetate hydrolase (FAH), leading to the accumulation of toxic metabolites and hepatorenal damage. Without treatment, it may progress to liver failure or hepatocellular carcinoma. Nitisinone is the treatment of choice, as it blocks the formation of toxic compounds. Early diagnosis is critical, particularly in contexts where newborn screening is not yet implemented.

Case report: We present the case of a 2-month-old infant, born to consanguineous parents, who presented with abdominal distension, vomiting, and diarrhea. The patient exhibited severe coagulopathy, metabolic acidosis, and ultrasound findings suggestive of acute abdomen. After transfer to a tertiary care center and completion of metabolic studies, a diagnosis of TYR1 was confirmed. Nitisinone therapy was initiated, with a favorable outcome following a complex stay in the intensive care unit.

Discussion: Although the use of nitisinone has significantly reduced the need for liver transplantation, further studies are needed to better understand its potential long-term neurocognitive effects. Continuous clinical and neuropsychological monitoring is recommended for affected individuals.

Conclusions: Early diagnosis of TYR1 through newborn screening enables prompt initiation of treatment with nitisinone and dietary management, significantly improving survival and reducing the risk of hepatocellular carcinoma. While treatment has dramatically changed the prognosis, uncertainties remain regarding long-term effects, particularly at the neurocognitive level. Comprehensive follow-up, including clinical, metabolic, and neuropsychological assessments, is essential.