Born at 27 weeks of gestation with classical PKU: challenges of dietetic management in a very preterm infant.

[classical phenylketonuria]

Few cases of premature infants with classical phenylketonuria (PKU ) have been reported . Treatment of these patients is challenging due to the lack of a phenylalanine (Phe )-free amino acid (AA ) solution for parenteral nutrition . A boy born at 27 weeks of gestation with a weight of 1000 g was diagnosed with classical PKU on day 7 because of highly elevated Phe level at newborn screening (2800 µmol /L ). Phe intake was suspended for 5 days and during this time intravenous glucose and lipids as well as small amounts of Phe-free formula through nasogastric tube were given . Because of insufficient weight gain attributable to deficiency of essential AA , a Phe-reduced , BCAA-enriched parenteral nutrition was added to satisfy AA requirements without overloading in Phe . Under this regimen , the boy started to gain weight , Phe plasma levels progressively reduced and normalized on day 19 . At the age of 40 months , the patient shows normal growth parameters (height 25 th percentile , weight 25 -50 (th ) percentile , head circumference 50 (th ) percentile ) with a normal result for formally tested psychomotor development (WPPSI-III ). The good outcome of the patient in spite of over 2 weeks of extremely high Phe concentrations suggests that the premature brain may still have enough plasticity to recover . Lacking a Phe-free intravenous AA solution , successful management of premature infants with PKU depends on the child 's tolerance of enteral nutrition . Although the coincidence of PKU and prematurity is rare , there is strong need for the development of an appropriate Phe-free amino acid solution for parenteral nutrition especially in case of gastro-intestinal complications of prematurity .