Phenylketonuria (PKU) is a genetic disorder that is characterized by an inability of the body to utilize the essential amino acid, phenylalanine. Amino acids are the building blocks for body proteins. ‘Essential’ amino acids can only be obtained from the food we eat as our body does not normally produce them. In ‘classic PKU’, the enzyme that breaks down phenylalanine phenylalanine hydroxylase, is completely or nearly completely deficient. This enzyme normally converts phenylalanine to another amino acid, tyrosine.
Without this enzyme, phenylalanine and its breakdown chemicals from other enzyme routes, accumulate in the blood and body tissues. 2. What is the newborn screening process for PKU? Newborn screening is the practice of testing every newborn for certain harmful or potentially fatal disorder’s that aren’t otherwise apparent at birth. It varies by state and is subject to change, especially given advancements in technology. Oregon tests for a different mix of diseases, (according to our just issued NW Regional Newborn Screening Program Practitioner’s Manual): • Hypothyroidism –incidence is 1:4,000.
This is a random rather than a recessive disease; • PHENYLKETONURIA — one out of 10,000 – 15,000 “Caucasian” births (less common in other races) hereditary recessive. • HEMOGLOBINOPATHIES — mainly a screen for sickle cell anemia (SCA). Incidence of 1 out of 400 in African American, lower in other groups; the state wide rate depends on the diversity of the local population… In Oregon it’s about 1 out of 15, 000. Also tests for beta thalassemia, or hemoglobin C. (note — The manual mentions that this is the first screening test which identifies carriers of a trait!
What to do with that information is governed by law (families MUST be informed, information kept confidential, documentation of any refusal of genetic counseling etc) • BIOTINDASE DEFICIENCY — one out of 60,000. • GALACTOSEMIA — two types — incidence is 1:60,000 for galactosemia and 1:150,000 with galactokinase deficiency. Recessively inherited. • MAPLE SYRUP URINE DISEASE (MSUD) –one out of 150,000. If kids born with PKU are put on a special diet right away, they can avoid the developmental delay the condition caused in past generations and lead normal lives.
When this disorder is detected early, feeding an infant a special formula low in phenylalanine can prevent mental retardation. A low-phenylalanine diet will need to be followed throughout childhood and adolescence and perhaps into adult life. This diet cuts out all high-protein foods, so people with PKU often need to take a special artificial formula as a nutritional substitute. Incidence: 1 in 10,000 to 25,000. One screening technique, the tandem mass spectrometry (or MS/MS), can screen for more than 20 inherited metabolic disorders with a single drop of blood.
3. Find the metabolic nutrition centers in your area (for every student in the group). Include their address and phone numbers as well as website address if applicable. Center for Nutrition Policy and Promotion 3101 Park Center Drive, 10th Floor Alexandria, VA 22302-1594 Ph: 703-305-7600 Fx: 703-305-3300 MyPyramid: Customer Support and Information Line, [email protected] usda. gov, 1-888-7-PYRAMID (888-779-7264; 8am to 3pm Eastern time, Monday-Friday, closed Federal holidays)
Public Affairs: John Webster, Director of Public Affairs,John. [email protected] usda. gov Website: http://www. cnpp. usda. gov/default. htm Newborn screening centre: Kentucky Newborn Screening Program 275 E. Main St. HS2W-C Frankfort, KY 40621 Phone: (502) 564-3756, ext. 3761 Toll Free: 800-462-6122, ext. 2 Fax: (502) 564-1510 Website: http://chfs. ky. gov/ Reference • Inherited Metabolic Diseases Clinic University of Colorado Health Sciences Center Denver, Colorado 80260 Distributed by: Mead Johnson Nutritionals Evansville, Ill. 47721