Our cases further highlight the broad phenotypic spectrum, showing intermediate types in addition to the three classically defined subtypes (neonatal intrahepatic cholestasis caused by citrin deficiency (‘NICCD’), failure to thrive and dyslipidaemia caused by citrin deficiency (‘FTTDCD’), adult-onset recurrent hyperammonaemia with neuropsychiatric symptoms in citrullinemia type II (‘CTLN2′)) and should prompt genetic evaluation early in the course of suggestive cases. This evidence concerns the gene SLC25A13 and Failure to thrive.