Compound heterozygous TRMU gene mutations in an infant with transient cholestasis and hyperlactatemia

The authors present an atypical case of an infant with unremarkable familiar, birth, and neonatal history who developed a mild/benign form of transient cholestasis. At admission, second- and third-level assessments were conducted, mitochondrial respiratory chain disorders were ex­cluded. The patient was accurately and promptly diagnosed through a clinically driven genetic test. The genetic analysis evidenced a compound heterozygous mutation c.383A>G (p.Tyr128Cys) of maternal origin and c.835G>A (p.Val279Met) of paternal origin in the TRMU gene associated to transient infantile liver failure, a condition known for its progressive and sometimes fatal prognosis. Biochemical test and patient’s clinical evolution were both good and there was no evidence of liver failure or dysfunction of other organs. This is the first-ever reported case of a patient with a TRMU pathological compound mutation with such good clinical evolution.