Mutations in MTU1 are associated with acute infantile liver failure, and this has been ascribed to a transient lack of cysteine, the sulfur donor for the thiouridylation reaction, resulting in a mitochondrial translation defect during early development.
Given that sulfur is a TRMU substrate and its availability is limited during the neonatal period, we propose that there is a window of time whereby patients with TRMU mutations are at increased risk of developing liver failure.