Posts Tagged ‘phenylketonuria’

Maternal PKU

Friday, July 24th, 2015

newborn-screening-picture1PKU or phenylketonuria is a condition in which your body can’t break down an amino acid called phenylalanine.

In the US, about 3,000 women of childbearing age have PKU. A woman with PKU can have a healthy baby but it is very important that she stay on a special diet to control her phenylalanine intake while she is pregnant. According to MotherToBaby, babies born to mothers with untreated PKU (women who are not on the special diet) are commonly born smaller, have microcephaly (an abnormally small head), intellectual disabilities, behavior problems, facial features similar to those of fetal alcohol syndrome, and have higher risks of heart defects.

Managing PKU during pregnancy

If you have PKU and are planning to get pregnant, it is very important that you talk to your health care provider. Many people with PKU now maintain their special diets throughout life. But if you have not been following your PKU diet, it is best to return to your PKU meal plan at least 3 months before you try to get pregnant.

PKU meal plans are different for everyone because people with PKU can tolerate different amounts of phenylalanine. For this reason, it is very important that you talk to health care providers who are familiar with managing PKU during pregnancy. Blood tests throughout pregnancy can help to monitor your phenylalanine levels and make sure that they are not too high. And your prenatal care provider may order ultrasounds to monitor your baby’s growth.

Will my baby have PKU?

If you have PKU, your baby has a chance to have PKU. Your baby has to inherit a mutation for PKU from both parents to have PKU. Whether or not your baby will have PKU depends on if your partner has PKU or is a PKU carrier. (A PKU carrier has one copy of the PKU mutation but does not have PKU.)

  • If you and your partner both have PKU, your baby will have PKU.
  • If you have PKU and your partner is a carrier, than there is a 50% chance your baby will have PKU and a 50% chance your baby will be a PKU carrier.
  • If you have PKU but your partner does not carry the gene change for PKU, then your baby will be a PKU carrier but will not have PKU.

If you are not sure if your partner is a PKU carrier, there are tests available that can help you find out. A genetic counselor can better help you understand your chances of passing PKU to your baby.

All babies born in the United States are tested for PKU through the newborn screening program. Babies born with PKU are immediately placed on a special diet that significantly reduces the amount of phenylalanine they consume. Babies who have PKU may never show symptoms if they are transitioned to a low-phenylalanine diet soon after birth.

Questions? Send them to AskUs@marchofdimes.org.

 

Phenylketonuria (PKU)

Friday, July 25th, 2014

newborn-screening-picture1Phenylketonuria (also called PKU) is a condition in which your body can’t break down an amino acid called phenylalanine. All babies born in the United States are tested for PKU through the newborn screening program in their state.

What is phenylalanine? 

Phenylalanine is an essential amino acid. Amino acids are building blocks for proteins. Our bodies need amino acids for proper growth and development but we cannot make them on our own. We need to get them from food sources. Phenylalanine is found in most foods that contain protein. This includes beef, poultry, fish, soy products, eggs, cheese, etc.

Once phenylalanine is in the body, it is converted into tyrosine, another amino acid. Tyrosine is then used by the body in a variety of ways, including the formation of chemicals that are necessary for your brain to function properly.

Why is phenylalanine harmful for people with PKU?

If your baby is born with PKU, she cannot break down phenylalanine. Phenylalanine then builds up in the blood and interferes with normal brain development. Without treatment, babies born with PKU begin to have signs of the condition at about 6 months of age. These include:

  • Jerky movements in arms and legs
  • Seizures
  • Skin rashes
  • Small head size
  • Developmental delays and behavioral problems

What causes PKU?

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 a change in a gene can cause it to not work correctly. This change is known as a mutation.

Your baby has to inherit a mutation for PKU from both parents to have PKU. If she inherits the mutation from just one parent, your baby is called a PKU carrier. A PKU carrier has one copy of the mutation but doesn’t have PKU.

How is PKU treated?

If your baby is diagnosed with PKU, then she will need to be on a special diet that significantly reduces the amount of phenylalanine she consumes. Ideally the diet would begin in the first few days of life. Babies who have PKU may never show symptoms if they are transitioned to a low-phenylalanine diet soon after birth.

If your baby is diagnosed with PKU, she will need to maintain a low-phenylalanine diet for life. If she were to stop controlling her dietary intake of phenylalanine, changes in the brain would occur, even well into adulthood. Women who have PKU and wish to become pregnant need to be on a very well controlled diet in order to protect their baby during pregnancy.

If you have any questions about this topic or other pregnancy and newborn health issues, please email the Pregnancy and Newborn Health Education Center at askus@marchofdimes.org.

Newborn screening and the March of Dimes

Tuesday, October 15th, 2013

newborn-screening-picture1This year, the March of Dimes and other health organizations are commemorating the 50th anniversary of newborn screening. In 1959, the March of Dimes began to explore newborn screening (NBS) as a means to detect and prevent the catastrophic consequences of metabolic conditions such as PKU (phenylketonuria) on a large scale. Subsequently, we funded research into several genetic and metabolic diseases that can be tested at birth, expanding the concept of newborn screening as an essential component of maternal/child health care delivery. We have worked tirelessly to promote expanded newborn screening programs in every state and to obtain federal guidelines for newborn screening, which has improved and saved the lives of countless thousands of affected children.

Linus Pauling (1901-1994), winner of the Nobel Prize in Chemistry in 1954, received one of the earliest basic research grants awarded by the March of Dimes. Dr. Pauling proposed the concept of molecular disease, using sickle cell anemia as a model. His finding that sickle hemoglobin differs in a measurable way from normal hemoglobin introduced the idea that heritable changes in the structure of a molecule could lead to improper function and result in disease. Dr. Pauling’s work laid the groundwork for the techniques used in newborn screening and diagnosis of sickle cell anemia.

Robert Guthrie, MD (1916-1995) was a March of Dimes grantee who developed a simple blood test to detect PKU, a cause of brain damage and intellectual disability. Dr. Guthrie refined an earlier PKU test, making it possible to analyze a dried spot of blood on filter paper instead of a liquid blood sample, an easier and inexpensive method that could be used on a mass scale. His breakthrough ushered in an era of state-mandated newborn screening programs. In 1963, Massachusetts became the first state to pass a law making the Guthrie PKU test mandatory, and New York followed soon after. The year 1963 marks the birth of state-mandated newborn screening, whose 50th anniversary we recognize this year.

The March of Dimes went on to award grants to develop inexpensive screening tests for congenital hypothyroidism, congenital adrenal hyperplasia, and biotinidase deficiency. In 1992, we called for every state to establish built-in safeguards for their newborn screening programs so that babies born with potentially catastrophic but treatable metabolic disorders would get help in a timely fashion. In 2000, we proposed a national standard for NBS and applauded an American Academy of Pediatrics review for improvements to the nation’s newborn screening programs, insisting that the primary consideration should be the health of the infant.

In 2008, Congress passed the Newborn Screening Saves Lives Act which established national guidelines on what conditions should be tested in newborn screening programs. The March of Dimes actively advocated in favor of its passage. At present, we promote 31 core conditions for newborn screening based on the U.S. Department of Health and Human Services Secretary’s Advisory Committee on Heritable Disorders in Newborns and Children.

Are artificial sweeteners safe?

Monday, March 14th, 2011

sweetenersWe’re often asked if it is safe to have foods with artificial sweeteners in them during pregnancy. The short answer is yes, when used in moderation. In the U.S., there are five different low-calorie sugar substitutes that have been approved by the FDA for general consumption, including by pregnant women.

Studies show that acesulfame potassium (Ace-K), aspartame, saccharin, neotame, and sucralose are all safe to consume during pregnancy.  Important note: Anyone with the inherited disease phenylketonuria, PKU, must steer clear of aspartame (sold as Nutrasweet or Equal) because it contains phenylalanine which their bodies cannot break down. Check with your health care provider about what’s best for you if you have PKU or carry the gene.

Specific concerns have been raised about saccharin because it crosses the placenta and can accumulate in the baby’s body. Studies have not proven it harmful, however, and both the American Dietetic Association and the American Diabetes Association have said that moderate use of saccharin during pregnancy should be fine.

So, yes it’s important to eat a healthy diet during pregnancy, but you can relax and have a diet soda every once in a blue moon if you’re really craving one. Just be mindful of all the foods you eat with low-calorie sweeteners (drinks, baked goods, candy, frozen desserts…) to keep your overall consumption of them down.