Variant clinical courses of 2 patients with neonatal intrahepatic cholestasis who have a novel mutation of SLC25A13

Deficiency of citrin due to mutations of the SLC25A13 gene causes not only adult-onset type II citrullinemia, but also neonatal intrahepatic cholestasis. Neonatal intrahepatic cholestasis is a self-limiting condition and spontaneously disappears by 12 months of age without special treatment. The natural history of patients with SLC25A13 mutations is not clear. Two patients with infantile hepatic dysfunction were found to have a novel mutation of the SLC25A13 gene. DNA analyses of SLC25A13 disclosed that the first patient was a compound heterozygote for the Ex16+74_IVS17-32del516 (del516-Ex16/IVS17) and IVS11+1G→A mutations and the second one a homozygote for the del516-Ex16/IVS17 mutation. It is predicted that the 516-base pair deletion mutation leads to a frameshift from codons 556 to 564, a premature termination at codon 565, and a truncated form of the citrin protein (normal, 675 amino acids). The first patient had disseminated intravascular coagulation associated with hepatic dysfunction in the neonatal period. The other patient had persistent cholestatic jaundice and underwent an operation to rule out bile duct atresia. Without specific treatment, both patients had a favorable clinical course. In conclusion, citrin deficiency resulting from the mutation of SLC25A13 presented variant clinical courses, followed by hypercitrullinemia and intrahepatic cholestasis in infancy. The conditions in the patients were self-limiting and spontaneously disappeared.