Individuals with PROP have an increased risk for certain secondary complications including pancreatitis and cardiomyopathy. Other, less common but serious, risks include cytopenia, optic neuropathy and late onset renal disease. While no specific nutritional interventions have been shown to prevent these complications, overall good adherence to recommended dietary management and aggressive intervention during intercurrent illnesses may be associated with better outcomes. Additional nutritional interventions, once complications have occurred, have been studied. Individuals with PROP who develop pancreatitis need to follow usual guidelines for nutrient intake during acute illness (see Q#2). In addition, recovery is hastened with the use of jejunal and/or parenteral nutrition to allow rest of the gastrointestinal tract. Cardiomyopathy can occur in the neonatal period or anytime over the lifetime of the individual, even in those who apparently have been adherent to their dietary recommendations. However, it has been demonstrated, by measurement in postmortem samples, that normal plasma carnitine levels, as a measure of adequate carnitine intake, may not reflect an apparent deficiency of carnitine in the cardiac tissue. While medical interventions are necessary to treat some of the symptoms of these secondary complications, the inability of usual nutrient interventions to be completely successful in preventing or treating the complications themselves, suggests mitochondrial dysfunction in PROP and the possible utility of antioxidant supplementation, although there is not sufficient evidence to support specific compounds and dosages.

Definitions of the protein terminology used throughout this guideline are listed in Appendix B.