Fatal Infantile Hepatic Dysfunction Associated With TRMU Gene Mutation and Aggravated by Cytomegalovirus Infection: A Unique Case.

Transient infantile liver failure due to tRNA 5-methylaminomethyl-2-thiouridylate methyltransferase (TRMU) gene mutation is a rare mitochondrial disease (MD) that typically presents within the first few months of life. We present the case of a 50-day-old female infant who was admitted with jaundice, hepatomegaly, lactic acidosis, and signs of liver dysfunction. Extensive metabolic and infectious investigations revealed a homozygous TRMU gene mutation and a high cytomegalovirus (CMV) viral load. The patient was treated with intravenous ganciclovir, supportive liver management, and metabolic correction; however, her clinical course was complicated by hepatic failure, coagulopathy, anemia, and ultimately cardiac arrest. This case represents the first reported instance of fatal infantile liver failure associated with a TRMU mutation, with CMV infection as a possible aggravating factor, from Lebanon.