The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Phenylketonuria (PKU) is an inherited disorder in which an enzyme (usually phenylalanine hydroxylase) crucial to the appropriate processing of the amino acid, phenylalanine is totally absent or drastically deficient. The result is that phenylalanine cannot be broken down, and it accumulates in large quantities throughout the body. Normally, phenylalanine is converted to tyrosine. Because tyrosine is involved in the production of melanin (pigment), people with PKU usually have lighter skin and hair than other family members. Without treatment, phenylalanine accumulation in the brain causes severe mental retardation. Treatment is usually started during babyhood; delaying such treatment results in a significantly lowered IQ by age one. Treatment involves a diet low in phenylalanine (look for warnings aimed at people with PKU on cans of diet drinks containing the artificial sweetener aspartame, which is made from phenylalanine). PKU strikes about one out of every 20,000 newborns. Because it is so important to start treatment immediately, many states require that all infants be tested for the disease within the first week of life.