RESUMEN
A 22-month-old female child with maple syrup urine disease (MSUD) presented with generalised oedema. Diagnostic evaluation revealed nephrotic range proteinuria, hypoalbuminaemia and dyslipidaemia supporting the diagnosis of nephrotic syndrome (NS). Diet, being at the core of the management plan for both MSUD and NS, necessitated regular monitoring and evaluation via dried blood spot collection of leucine. The opposing requirement for total protein for both disorders (that is protein restriction in MSUD and protein supplementation in NS) prompted a careful balancing act of the dietary management. The monitoring, which revealed normal leucine levels on multiple determinations, allowed an eventual increase in dietary protein and daily administration of albumin to address the NS. Dietary protein increase, both in total protein (3.5 g/kg/day) and natural protein (1 g/kg/day) levels, was instituted. It was observed that NS does not trigger leucinosis and allowed easing of protein restriction in MSUD.