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Propionic acidemia

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Also known as:
  • PROP
  • ketotic glycinemia
  • ketotic hyperglycinemia
  • PCC deficiency
  • PA
  • propionic aciduria
  • propionyl-CoA carboxylase deficiency

Propionic acidemia (PROP) is an inherited condition in which the body is unable to break down certain proteins and fats.  It is considered an organic acid condition because it can lead to a harmful amount of organic acids and toxins in the body. If left untreated, it can cause brain defects or even death.  However, if the condition is identified early in life and proper treatment is begun, children with PROP can minimize some of the early complications of the condition.

Follow-Up Testing

Your baby’s doctor or the state newborn screening program may ask you if your baby is showing any of the signs of PROP (see Early Signs below).  If your baby has certain signs, your baby’s doctor may suggest starting immediate treatment.

If your baby’s newborn screening result for propionic acidemia (PROP) was out of the normal range, your baby’s doctor or the state screening program will contact you to arrange for your baby to have additional testing. It is important to remember that an out-of-range screening result does not necessarily mean that your child has the condition. An out-of-range result may occur because the initial blood sample was too small or the test was performed too early. However, a few babies do have the condition, so it is very important that you go to your follow-up appointment for a confirmatory test. Because the harmful effects of untreated PROP can occur within days after birth, follow-up testing must be conducted as soon as possible to determine whether or not your baby has the condition.

Follow-up testing will involve checking your baby’s urine and blood samples for harmful levels of acids and toxins. Certain acids and toxins build up in the body when a child has an organic acid condition, so studying the levels of these substances in your baby’s body can help doctors determine if your child has a condition. High levels of acylcarnitine in the blood or organic acids in the urine can be signs of PROP. Sometimes follow-up testing may also include testing a very small sample of skin.


About Propionic acidemia

Early Signs

Signs of propionic acidemia (PROP) usually start within a few days after birth. In some cases, signs may not appear until childhood or later. This is why early screening and identification is so important.

Early signs of PROP include:

  • Poor feeding
  • Vomiting
  • Loss of appetite
  • Weak muscle tone (known as hypotonia)
  • Sleeping longer or more often 
  • Tiredness

Many of these signs may occur when your baby eats foods that his or her body cannot break down. They can be triggered by long periods of time without eating, illnesses, and infections.

If your baby shows any of these signs, be sure to contact your baby’s doctor immediately.

Treatment

Children with propionic acidemia (PROP) need to limit certain proteins and fats in their diets because their bodies cannot break down these substances. From birth, your baby will need to be on a carefully planned diet. There are special formulas available for children with PROP (see Accessing Care below). These formulas will likely need to be continued through adulthood.

Your baby will also need to eat often. Long periods without food, as well as fever and infections, can trigger many of the signs mentioned in the Early Signs section.

Supplements and Medications

Your baby might also need to take supplements for L-carnitine and biotin. These are natural compounds that help break down fats and proteins, but they may not be naturally occurring in your baby’s body. Your doctor will need to write you a prescription for these supplements.

Your doctor may also prescribe antibiotics to help reduce the levels of propionic acid in your baby’s body.

Expected Outcomes

Treatment for propionic acidemia (PROP) can help reduce some of the early complications of the condition. It is possible for children receiving treatment for PROP to have learning disabilities or developmental delays. It is important to screen for and treat PROP because, if left untreated, babies can die within their first year of life.

Causes

When we eat food, enzymes help break it down. Some enzymes break down proteins into their building blocks, called amino acids. Other enzymes break down the amino acids. In propionic acidemia (PROP), the enzyme propionyl-CoA carboxylase (PCC) is not working correctly.

PCC’s job is to break down the amino acids isoleucine, valine, methionine, and threonine and a type of fat called odd chain fats.

If your baby has PROP, then his or her body either does not make enough or makes non-working PCC enzymes. When PCC is not working correctly, isoleucine, valine, methionine, threonine and odd-chained fats cannot be broken down. This causes other toxins in the body to build up.

PROP is an autosomal recessive genetic condition. This means that a child must inherit two copies of the non-working gene for PROP, one from each parent, in order to have the condition. The parents of a child with an autosomal recessive condition each carry one copy of the non-working gene, but they typically do not show signs and symptoms of the condition. While having a child with PROP is rare, when both parents are carriers, they can have more than one child with the condition. Learn more about autosomal recessive inheritance.


Support for Propionic acidemia

Support Services

Support groups can help connect families who have a child or other family member affected with propionic acidemia with a supportive community of people who have experience and expertise in living with the condition. These organizations offer resources for families, affected individuals, health care providers, and advocates.

Accessing Care

Work with your baby’s doctor to determine the next steps for your baby’s care. Your baby’s doctor may help you coordinate care with a physician who specializes in metabolism, a dietician who can help plan your child’s specialized diet, or other medical resources in your community. Some children with propionic acidemia (PROP) have developmental delays. If you think that your baby is not meeting his or her developmental milestones, ask your baby’s health care provider about the next steps in accessing a developmental evaluation and care.

Because PROP is a genetic condition, you may want to talk with a genetics specialist. A genetic counselor or geneticist can help you understand the causes of the condition, discuss genetic testing for propionic acidemia, and understand what this diagnosis means for other family members and future pregnancies. Speak with your baby’s doctor about getting a referral. The Clinic Services Search Engine offered by the National Coordinating Center for the Regional Genetic and Newborn Screening Service Collaboratives and the Find a Genetic Counselor tool on the National Society of Genetic Counselors (NSGC) website are two good resources for you or your baby's health care provider to use to identify local specialists.

Families' Experiences

Check out the story of Cadence, a child with propionic acidemia (PROP). Cadence’s mother writes about the joys and challenges of a family affected by PROP

Read the story of a teenager named Aidan with PROP. Aidan’s story shows what a huge difference a supportive community can make.

Gwen and Alison are two young girls with PROP whose parents became friends after their diagnoses. Their stories show not only that every family has a unique experience with the condition, but also that every child with the condition has a different experience. Read about Gwen and Alison here

See pictures and stories of dozens of families living with PROP on the Propionic Acidemia Foundation’s website.


States Screening for Propionic acidemia

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