Single-gene autosomal recessive disorders and Prader-Willi syndrome: an update for food and nutrition professionals.

ABSTRACT

This review is an update for food and nutrition professionals about single-gene autosomal recessive disorders and Prader-Willi syndrome. These disorders highlight the application of new genetic tools for screening newborns for conditions managed by medical nutrition therapy. Early detection and dietary treatment have been crucial since the 1960s for patients diagnosed with phenylketonuria. The same concept of reducing the dietary substrate that accumulates in disease is applied today for some conditions difficult to diagnose a decade ago. More than 6,000 human single-gene disorders have been identified to date, including more than 100 protein-based metabolic disorders. Tandem mass spectrometry has facilitated newborn screening for more disorders at low cost and high speed. Presently, screening newborns for 29 disorders is recommended in the United States and many states are doubling or tripling the number of tests offered in their screening programs. Complex dietary therapies have evolved for rare disorders, such as fatty acid oxidation, urea cycle, organic acid metabolism, glycogen storage, and energy production. Diagnosis-specific therapy may challenge routine dietary recommendations, such as encouraging fatty and sugary foods or avoiding fruits and milk, and treatment options have spawned a market in special formulas and substitute foods; recommended references and Web sites are provided to assist food and nutrition professionals in navigating this territory. Single-gene autosomal recessive disorders have increased the need for, and created opportunities for, food and nutrition professionals, especially those who enjoy biochemistry.