Phenylketonuria
Introduction Phenylketonuria (PKU) is a rare genetic condition that is present from birth. The body is unable to break down a substance called phenylalanine, which builds up in the blood and brain. High levels of phenylalanine can damage the brain. PKU is treated with a special low-protein diet, which reduces the levels of phenylalanine in the body and prevents brain damage. PKU doesn't usually cause any symptoms if treatment is started early – but if it isn't treated, damage to the brain and nervous system can lead to: learning disabilities behavioural difficulties epilepsy High levels of phenylalanine can also cause eczema. Read more about the symptoms of phenylketonuria. What happens? The body takes in phenylalanine in the form of protein in food. Phenylalanine is normally broken down in the body by an enzyme called phenylalanine hydroxylase. In people with PKU, this enzyme does not work properly because of a genetic mutation (alteration in their DNA). As a result, phenylalanine levels in their blood, and other tissues, rise. Read more about the causes of phenylketonuria. How common is it? PKU is rare. Both sexes are affected equally by PKU. The condition is slightly more common in white people, particularly those of Celtic descent (Scottish, Irish and Welsh). It is very rare in black and Japanese people. All babies born in developed countries are routinely screened for high phenylalanine levels. This is done using the heel prick test and is carried out during the first week of a baby’s life. During the test, a blood sample is taken from the baby’s heel to test for a number of rare but serious conditions, including PKU. If phenylketonuria is picked up, further tests will be arranged to confirm the diagnosis. Read more about diagnosing phenylketonuria. Without t Continue reading >>
Phenylalanine
Overview Phenylalanine is an essential amino acid (a building block for proteins in the body), meaning the body needs it for health but cannot make it. You have to get it from food. Phenylalanine is found in 3 forms. L-phenylalanine, the natural form found in proteins D-phenylalanine (a mirror image of L-phenylalanine that is made in a laboratory) DL-phenylalanine, a combination of the 2 forms The body changes phenylalanine into tyrosine, another amino acid that is needed to make proteins and brain chemicals, including L-dopa, epinephrine, norepinephrine, and thyroid hormones. Because norepinephrine affects mood, different forms of phenylalanine have been proposed to treat depression. Symptoms of phenylalanine deficiency include: Confusion Lack of energy Depression Decreased alertness Memory problems Lack of appetite On the other hand, a rare metabolic disorder called phenylketonuria (PKU) occurs in people who are missing an enzyme that the body needs to use phenylalanine. That causes high levels of phenylalanine to build up. If it is not treated before 3 weeks of age, PKU can cause severe, irreversible intellectual disability. In the United States, newborns are tested for PKU during the first 48 to 72 hours of life. Older, untreated children become hyperactive with autistic behaviors, including purposeless hand movements and rhythmic rocking. People with PKU must eat a diet that avoids phenylalanine and take tyrosine supplements for optimal brain development and growth. Compliance with treatment in people with PKU has a greater impact on cognition during the first 12 years of life compared to the influence beyond 12 years. Uses Chronic pain D-phenylalanine (but not L-phenylalanine) has been proposed to treat chronic pain. Two studies that appeared to show positive resu Continue reading >>
Pku (phenylketonuria) In Your Baby
Phenylketonuria (also called PKU) is a condition in which your body can’t break down an amino acid called phenylalanine. Amino acids help build protein in your body. Without treatment, phenylalanine builds up in the blood and causes health problems. In the United States, about 1 in 10,000 to 15,000 babies is born with PKU each year. The illness happens in all ethnic groups. But it’s more common in people who are Native American and Northern European than those who are African-American, Ashkenazi Jewish or Japanese. PKU is inherited. This means it’s passed from parent to child through genes. A gene is a part of your body’s cells that stores instructions for the way your body grows and works. Genes come in pairs—you get one of each pair from each parent. Sometimes the instructions in genes change. This is called a gene change or a mutation. Parents can pass gene changes to their children. Sometimes a gene change can cause a gene to not work correctly. Sometimes it can cause birth defects or other health conditions. A birth defect is a health condition that is present in a baby at birth. Your baby has to inherit a gene change for PKU from both parents to have PKU. If she inherits the gene from just one parent, she has the gene change for PKU, but she doesn’t have PKU. When this happens, your baby is called a PKU carrier. A PKU carrier has the gene change but doesn’t have PKU. How do you know if your baby has PKU? All babies have a newborn screening test for PKU. Newborn screening checks for serious but rare conditions at birth. It includes blood, hearing and heart screening. With newborn screening, PKU can be found and treated early so babies can grow up healthy. Before your baby leaves the hospital, his health care provider takes a few drops of blood from hi Continue reading >>
Phenylketonurics - Contains Phenylalanine
Have you ever looked at the label on a diet soda can and seen the warning: ? I personally know of several people who refuse to drink diet soda because the word "phenylketonurics" sounds too scary! What does "phenylketonurics" mean? Is it something you can catch from diet soda? Well, let me take the opportunity to answer these questions. "Phenylketonurics" is NOT something you can catch from diet soda! This long, scary-sounding word is included in a warning at the end of the ingredients list on some products, but it is NOT an ingredient these products. "Phenylketonurics" is the term used to refer to people that have the metabolic disorder Phenylketonuria, or PKU for short. So - kind of like how the word "diabetics" refers to people that have "diabetes", "phenylketonurics" refers to the people that have "phenylketonuria". I myself, am one of these phenylketonurics and the warning on diet soda cans is included merely to inform people like me that the product contains the synthetic chemical ASPARTAME . People that have the disorder PKU cannot consume any product that contains aspartame, for reasons which I will elaborate on below. Two additional questions that people often ask when they learn of the true meaning of the warning label on diet soda are - Do I have PKU? How do I know that I don't have PKU? Well, if you have reached an age where you have the desire to drink diet soda and you still have the mental capacity to question whether or not you have PKU, the odds are that you don't have the disorder. Phenylketonuria is a genetic metabolic disorder that results when the PKU gene is inherited from both parents. When babies are born in the United States, a heel stick blood test is done to test for various disorders - PKU is one of the disorders that is tested for. It is ver Continue reading >>
Diagnosis
Print Newborn blood testing identifies almost all cases of phenylketonuria. All 50 states in the United States require newborns to be screened for PKU. Many other countries also routinely screen infants for PKU. If you have PKU or a family history of it, your doctor may recommend screening tests before pregnancy or birth. It's possible to identify PKU carriers through a blood test. Testing your baby after birth A PKU test is done a day or two after your baby's birth. The test isn't done before the baby is 24 hours old or before the baby has ingested some protein in the diet to ensure accurate results. A nurse or lab technician collects a few drops of blood from your baby's heel or the bend in your baby's arm. A laboratory tests the blood sample for certain metabolic disorders, including PKU. If you don't deliver your baby in a hospital or are discharged soon after the birth, you may need to schedule a newborn screening with your pediatrician or family doctor. If this test indicates your baby may have PKU: Your baby may have additional tests to confirm the diagnosis, including more blood tests and urine tests You and your baby may undergo genetic testing to identify gene mutations Treatment The main treatment for phenylketonuria includes: A lifetime diet with very limited intake of protein, because foods with protein contain phenylalanine Taking a PKU formula — a special nutritional supplement — for life to make sure you get enough essential protein (without phenylalanine) and nutrients that are crucial for growth and general health A safe amount of phenylalanine differs for each person with PKU and can vary over time. In general, the idea is to consume only the amount of phenylalanine that's necessary for normal growth and body processes, but no more. Your doctor ca Continue reading >>
Diabetes: Sugar Substitutes & Nonnutritive Sweeteners
What are nonnutritive sweeteners? Nonnutritive sweeteners are substances that are used instead of sugars (i.e., sucrose, corn syrup, honey, agave nectar) to sweeten foods, beverages and other products, such as oral care products and certain medications. Nonnutritive sweeteners (also called sugar substitutes or artificial sweeteners) contain few or no calories or nutrients. Artificial sweeteners may be derived from plants or herbs, or even sugar itself. They have a greater intensity of sweetness compared with sugar, so smaller quantities are needed for flavoring foods and beverages. Some artificial sweeteners are not metabolized, meaning that they pass through the digestive tract essentially unchanged. The seven nonnutritive sweeteners that have been approved by the U.S. Food and Drug Administration (FDA) are aspartame, acesulfame potassium, luo han guo (monk) fruit extract, neotame, saccharin, stevia and sucralose. Aspartame (Equal® or NutraSweet®) is about 200 times sweeter than table sugar. Aspartame is used as a tabletop sweetener found in a wide variety of foods and beverages, including cereals, yogurt, frozen and gelatin desserts, candy, sugar-free gum, juices, diet sodas, and many other products. It is also used in drugs such as vitamin supplements and laxatives. Acesulfame potassium (Sunett® and Sweet One®) is generally used in combination with other non-nutritive sweeteners and is frequently found in sugar-free sodas. Neotame is also used in low-calorie foods and beverages, but to a lesser extent than other sweeteners. It is about 7,000 to 13,000 times sweeter than sugar. It is a derivative of the amino acids phenylalanine and aspartic acid. Saccharin (Sweet ‘n Low®, Sweet Twin®, and Sugar Twin®) is the oldest artificial sweetener on the market. It was Continue reading >>
What Is The Diet For Pku?
What is Included in a Low Phenylalanine Food Pattern? The diet for PKU consists of a phenylalanine-free medical formula and carefully measured amounts of fruits, vegetables, bread, pasta, and cereals. Many people who follow a low phenylalanine (phe) food pattern eat special low protein breads and pastas. They are nearly free of phe, allow greater freedom in food choices, and provide energy and variety in the food pattern. What is Not Included in a Low Phenylalanine Food Pattern? Foods that contain large amounts of phe must be eliminated from a low phe diet. These foods are high protein foods, such as milk, dairy products, meat, fish, chicken, eggs, beans, and nuts. These foods cause high blood phe levels for people with PKU. Aim for healthy food choices This target is an easy way to visualize the foods allowed on the diet for PKU. The phenylalanine-free formula, such as Phenyl-Free*, is the center of the target diet. As the foods get further away from the bull's-eye, they are higher in phenylalanine. The foods outside the target are not included in the low-phenylalanine meal plan. How Can This Food Pattern be Enough? It is not unusual for someone who follows a low phe diet to have 2 kinds of vegetables and a baked potato for dinner. However, if these foods were the only foods a person consumed, his or her diet would be lacking protein, vitamins, and minerals. That is where the special formula comes in. A special phenylalanine-free formula, such as Phenyl-Free*, contains protein, vitamins, minerals and energy (calories) with no phenylalanine. With formula, a person with PKU gets plenty of protein, without the side effects of the high phe content of most foods. The phenylalanine-free formula is the most important part of the diet for PKU. How Long Must a Person With PKU F Continue reading >>
Phenylketonuria
Phenylketonuria (PKU) is a rare but potentially serious inherited disorder. Our bodies break down protein in foods like meat and fish into amino acids, which are the "building blocks" of protein. These amino acids are then used to make our own proteins. Any amino acids that aren't needed are broken down further and removed from the body. People with PKU can't break down the amino acid phenylalanine, which then builds up in the blood and brain. This can lead to brain damage. Diagnosing PKU At around 5 days old, babies are offered newborn blood spot screening to check if they have PKU or a number of other conditions. This involves pricking your baby's heel to collect drops of blood to test. If PKU is confirmed, treatment will be given straight away to reduce the risk of serious complications. Treatment includes a special diet and regular blood tests. With early diagnosis and the correct treatment, the majority of children with PKU are able to live healthy lives. About 1 in 10,000 babies born in the UK has PKU. Symptoms of PKU PKU doesn't usually cause any symptoms if treatment is started early. Without treatment, PKU can damage the brain and nervous system, which can lead to learning disabilities. Other symptoms of untreated PKU include: behavioural difficulties – such as frequent temper tantrums and episodes of self-harm fairer skin, hair and eyes than siblings without the condition (phenylalanine is involved in the body's production of melanin, the pigment responsible for skin and hair color) recurrent vomiting jerking movements in arms and legs musty smell on the breath, skin and urine Treating PKU Diet The main treatment for PKU is a low-protein diet that completely avoids high-protein foods (such as meat, eggs and dairy products) and controls the intake of many oth Continue reading >>
Metabolic Disorders: Pku, Msud, And Nutrition
What are metabolic disorders? Metabolic disorders are genetic diseases that interfere with the body's ability to process specific substances. Often, the body is missing an enzyme that is needed to process a certain type of amino acid. As a result, these acids can build up in the body causing health problems. Many metabolic disorders need special dietary therapy. Dietary therapy is a way of limiting the intake of the substance the body does not process well by avoiding certain foods and eating a special diet. People with metabolic disorders need ongoing counseling and monitoring by a team of physicians, nurses, genetic counselors, social workers, and dietitians for improved health and longevity. PKU and MSUD Two common diet-affected metabolic disorders are PKU or phenylketonuria, and Maple Syrup Urine Disease (MSUD). Both conditions involve deficiency in an enzyme that breaks down an amino acid into another compound. This means that the essential amino acid tends to build up in the body, causing problems. Phenylketonuria (PKU) PKU is a complete absence or deficiency in phenylalanine hydroxylase (PAH), an enzyme involved in metabolizing or converting the amino acid phenylalanine into tyrosine, another amino acid. PAH deficiency results in high levels of blood phenylalanine and an accumulation of phenylketones in the urine. Partial deficiency of the enzyme results in hyperphenylalaninemia. In this condition, the child has elevated blood phenylalanine, although it is not quite as high as when there is a complete absence of PAH. In hyperphenylalaninemia, phenylketones do not accumulate. Unless it is recognized and treated soon after birth, PKU will cause brain damage. In the United States, PKU is most common in white and Native Americans and less common in African American, Continue reading >>
Phenylketonuria
Phenylketonuria (PKU) is inherited, which means it is passed down through families. Both parents must pass on a nonworking copy of the gene in order for a baby to have the condition. Babies with PKU are missing an enzyme called phenylalanine hydroxylase, which is needed to break down the essential amino acid phenylalanine. Phenylalanine is found in foods that contain protein. Without the enzyme, levels of phenylalanine build up in the body. This buildup can harm the central nervous system and cause brain damage. Continue reading >>
Artificial Sweeteners And Diabetes
Is it possible to eat sweets when you have diabetes? The answer is "yes." But when you’re trying to satisfy your sweet tooth, it can be hard to know what to reach for at the grocery store (sugar-free this or low-calorie that). So, use this primer to help you choose wisely. The Sweet Facts When you’re comparing sweeteners, keep these things in mind: Sugars are naturally occurring carbohydrates. These include brown sugar, cane sugar, confectioners’ sugar, fructose, honey, and molasses. They have calories and raise your blood glucose levels (the level of sugar in your blood). Reduced-calorie sweeteners are sugar alcohols. You might know these by names like isomalt, maltitol, mannitol, sorbitol, and xylitol. You'll often find them in sugar-free candy and gum. They have about half the calories of sugars and can raise your blood sugar levels, although not as much as other carbohydrates. Artificial sweeteners are considered "free foods." They were designed in a lab, have no calories, and do not raise your blood sugar levels. Types of Artificial Sweeteners Artificial low-calorie sweeteners include: Saccharin (Sweet'N Low, Sugar Twin). You can use it in both hot and cold foods. Avoid this sweetener if you are pregnant or breastfeeding. Aspartame (NutraSweet, Equal). You can use it in both cold and warm foods. It may lose some sweetness at high temperatures. People who have a condition called phenylketonuria should avoid this sweetener. Acesulfame potassium or ace-K (Sweet One, Swiss Sweet, Sunett). You can use it in both cold and hot foods, including in baking and cooking. Sucralose (Splenda). You can use it in hot and cold foods, including in baking and cooking. Processed foods often contain it. Advantame can be used in baked goods, soft drinks and other non-alcoholic bev Continue reading >>
Genetic Fact Sheets For Parents
Disorder name: Phenylketonuria Acronym: PKU This fact sheet contains general information about PKU. Every child is different and some of these facts may not apply to your child specifically. Certain treatments may be advised for some children but not others. All children with PKU should be followed by a metabolic doctor in addition to their primary care provider. If your newborn has had a ‘presumptive positive screen for PKU’ as a result of newborn screening, it does not yet mean that he or she has PKU. There are other tests that need to be done to confirm whether your baby actually has PKU. Some babies are found not to have PKU and do not need treatment. Others are found to have a milder condition called “hyperphenylalaninemia” - also called ‘hyperphe’ or ‘non-PKU HPA.’ Many children with non-PKU HPA do not need treatment. There is also another form of non-PKU HPA that is treated with a medication called BH4 (tetrahydrobiopterin). This condition is rare (less than 2% of cases). Blood and urine tests can be done to determine whether your child has this form of non-PKU hyperphe. This fact sheet contains information about classic PKU only. Therefore, the details below are relevant only to babies who have been confirmed to have classic PKU. It does not contain information on non-PKU HPA or other variants. What is PKU? PKU stands for “phenylketonuria”. It is one type of amino acid disorder. People with PKU have problems breaking down an amino acid called phenylalanine from the food they eat. Amino Acid Disorders: Amino acid disorders (AAs) are a group of rare inherited conditions. They are caused by enzymes that do not work properly. Protein is made up of smaller building blocks called amino acids. A number of different enzymes are needed to process thes Continue reading >>
Phenylketonuria (pku) - Aspartame
Phenylketonuria (PKU) is a rare, inherited metabolic disease that results in mental retardation and other neurological problems when treatment is not started within the first few weeks of life. When a very strict diet is begun early and well-maintained, effected children can expect normal development and a normal life span. Elevations of blood phenylalanine are dangerous for those with PKU, and require treatment and modification. A child with a level less than 6 mg/dl does not need to be on a special diet and is not risk for mental retardation, but should avoid aspartame at all cost due to the 50% phenylalanine levels. Scientists have been able to show that carriers had higher phenylalanine levels in their urine than non-carriers. Phenylalanine Hydroxylase The disease arises from the absence of a single enzyme (phenylalanine hydroxylase). This enzyme normally converts the essential amino acid, phenylalanine, to another amino acid, tyrosine. Failure of the conversion to take place results in a buildup of phenylalanine. Through a mechanism that is not well understood, the excess phenylalanine is toxic to the central nervous system and causes the severe problems normally associated with PKU. Not every child has the same degree of enzyme deficiency, however; some have enough enzyme activity that the diet can be quite liberal, while others must have the very strict diet. The nature of the diet for an individual child must be determined by an experienced PKU treatment program. Phenylketonuria is carried through a "recessive" gene. The incidence of carriers in the general population is approximately one in fifty people. Although PKU affects only one out of every approximately 10,000 babies born in the US, there are several hundred babies diagnosed and put on a strict diet each Continue reading >>
Phenylketonuria
Phenylketonuria Definition Phenylketonuria (PKU) can be defined as a rare metabolic disorder caused by a deficiency in the production of the hepatic (liver) enzyme phenylalanine hydroxylase (PAH). PKU is the most serious form of a class of diseases referred to as "hyperphenylalaninemia," all of which involve above normal (elevated) levels of phenylalanine in the blood. The primary symptom of untreated PKU, mental retardation, is the result of consuming foods that contain the amino acid phenylalanine, which is toxic to brain tissue. PKU is an inherited, autosomal recessive disorder. It is the most common genetic disease involving "amino acid metabolism." PKU is incurable, but early, effective treatment can prevent the development of serious mental incapacity. Description PKU is a disease caused by the liver's inability to produce a particular type of PAH enzyme. This enzyme converts (metabolizes) the amino acid called phenylalanine into another amino acid, tyrosine. This is the only role of PAH in the body. A lack of PAH results in the buildup of abnormally high phenylalanine concentrations (or levels) in the blood and brain. Above normal levels of phenylalanine are toxic to the cells that make up the nervous system and causes irreversible abnormalities in brain structure and function in PKU patients. Phenylalanine is a type of teratogen. Teratogens are any substance or organism that can cause birth defects in a developing fetus. The liver is the body's chief protein processing center. Proteins are one of the major food nutrients. They are generally very large molecules composed of strings of smaller building blocks or molecules called amino acids. About twenty amino acids exist in nature. The body breaks down proteins from food into individual amino acids and then reass Continue reading >>
Diet Intervention Guidelines For Adults With Untreated Pku
by Barbara E. Dolan, RN, MSN Nurse Counselor for Genetics, Redwood Coast Regional Center, Ukiah, CA Richard Koch, MD Division of Medical Genetics, Children’s Hospital of Los Angeles and The Department of Pediatrics, University of Southern California, School of Medicine, Los Angeles, CA Christina Bekins, MS, RD Nutrition Consultant, Calistoga, CA Virginia Schuett, MS, RD Nutritionist and Director, National PKU News, Seattle, WA Acknowledgments The authors applaud the “outreach clinic model” staffed by specialists including Richard Goldwasser, MD, psychiatrist. We wish to thank Kathleen Schmidt Yule, RN, MS, UCS, NBS Program; Kathleen Dall, RD, Scientific Hospital Supplies, Inc.; The Inherited Metabolic Disease Clinic, Denver, CO; and Steven Yannicelli, MMSc, RD and Phyllis Acosta, PhD, RD, Ross Laboratories for their interest and guidance in the beginning months of this project. We are grateful for the interest, confidence and love of adult care providers and their families, and for their willingness to collaborate and share with us. Note: Before applying any of the information contained in these guidelines to treatment of PKU, you must consult with a PKU specialist. The guidelines do not give advice or recommendations for individuals, whose unique medical, nutritional, and other needs must be considered. Contents Introduction Overcoming Obstacles to Treatment: Obtaining Information, Guidance, and SupportStarting and Maintaining the Low PHE Diet for Adults Other Treatment Considerations Diet Resources Appendix Sample Menus (will be available at a later date on the PKU News web site) Introduction Purpose and Approach of the Guidelines The purpose of these guidelines is to present an organized way to start and maintain a phenylalanine (PHE)-restricted diet for a prev Continue reading >>
