Biotechnology Company May Help Patients with Phenylketonuria Eat Protein

According to a recent article, patients with phenylketonuria (PKU) are unable to eat proteins because of their condition. However, a new probiotic might be the solution.

Phenylketonuria (PKU)

PKU is a rare genetic condition that causes a buildup of the amino acid phenylalanine. Amino acids are obtained through the dietary intake of protein, and phenylalanine is present in protein as well as some artificial sweeteners. The buildup of phenylalanine in the body can lead to serious health problems. PKU affects 1 in 10,000-15,000 births.


The symptoms of PKU are caused by a lack of breakdown and elimination of the amino acid phenylalanine. Newborns with PKU do not exhibit symptoms immediately after birth. Symptoms appear within the first few months of life. Early detection of PKU is important to avoid irreversible health problems. Symptoms of PKU include:

  • Seizures
  • Developmental delays
  • Intellectual delays
  • Hyperactivity
  • Decreased bone strength
  • Abnormally small head (microcephaly)
  • Fair skin and eyes due to poor melanin production
  • Skin rashes such as eczema
  • Musty odor to breath, skin and/or urine
  • Heart defects

Issues With Protein

For patients with PKU, their rare genetic variation affects their body’s ability to digest one of the chemicals of proteins, phenylalanine. Therefore, the toxins can build up in their brain leading to mental retardation.

The Probiotic

Synlogic, a biotech startup in Boston, is looking to use a probiotic to digest the proteins before they have the opportunity to enter the patient’s bloodstream and brain. So far, the company is focusing on E. coli bacterium, as it has been used for over a century as a probiotic. They have also looked at a number of gene variants to figure out which ones produce enzymes that are the most efficient at getting rid of the target proteins.

How To Handle a PKU Diagnosis

A PKU diagnosis can be overwhelming at first, however, there are steps that can be taken to manage the disease. The most effective management is through a very restricted diet. Of course, there are complications with this diet since it majorly restricts the amount of protein a patient is getting, but that can be negated by a patient taking a medical formula with digestible proteins in it.

Staying On Track

Since patients are forced to stick to a very strict diet, temptations follow them everywhere. As they get to young adult age and are given more freedoms, it can lead them to veer slightly from their recommended diets. There is an estimated 90 percent of adults diagnosed with PKU that are off treatment. This is due to fatigue from following a strict diet with unappetizing formula and lapses in insurance coverage.


There are not many drugs that are used for the treatment of PKU, but there are two that provide patients with some benefits.

One of the drugs is Kuvan, a pill or powder that corrects a proteins folding error making it so that the proteins in food can be digested. It is typically used along-side a protein-restricted diet. The issue with this drug is that it unfortunately does not work for every patient’s genetic mutation. In addition, this drug can cost anywhere between $100,000 and $200,000 a year.

The other drug is Palynziq, which is injected daily once or twice a day. This drug has the ability to lower the Phe to normal levels, but it is very hard for patients to use. Furthermore, there can be reactions at the injection site and can cause a patient to develop anaphylaxis (allergic reaction). This drug is even more expensive than the alternative Kuvan.

The Future

Patients diagnosed with PKU are eagerly looking for advances in treatment options that will work more efficiently and conveniently in their lives. Synlogic’s efforts to look into a probiotic that may help is giving patients hope. So far, the company has had success, and patients and doctors alike look forward to the advances the company is trying to make.

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