Patients & Families

Homology Medicines is focused on advancing our genetic medicines platform as one-time treatments and potential cures for patients with rare diseases

Ava’s Story

Ava rock climbing

Ava is a seventh grader who enjoys doing aerial acrobatics in her spare time. When she thinks about the future, she isn’t sure where her path will lead, but she says she will need to choose a profession that will allow her to be able to access and pay for the medications she takes to manage the rare disease phenylketonuria (PKU).

Ava’s mother Sharla received “the call” when Ava was five days old. The state lab said one of Ava’s tests from her newborn screening panel came back abnormal and that a confirmatory test was needed to determine whether her baby had the genetic disorder PKU. Sharla had never heard of PKU so when a doctor said it meant her daughter would need to be on a low-protein diet for life, she assumed that meant limiting meat, dairy and beans – an inconvenient but manageable adjustment. Like many others, at that time, Sharla did not realize the true extent of what the diet entails or the reason why it is so important.

Someone with PKU has a variant in the PAH gene that prevents the body from metabolizing, or breaking down, phenylalanine (Phe). Phe is an amino acid found in dietary protein and some artificial sweeteners. The gene variant stops the enzyme phenylalanine hydroxylase (PAH) from forming correctly, so the person’s body cannot break down Phe and convert it to neurotransmitters, which help with signaling in the brain; and melanin, which provides pigmentation to the skin and hair. Additionally, when Phe builds up in the brain, it can be toxic, leading to significant neurocognitive impairment.

Limiting protein, and therefore Phe, in a person’s diet has been the standard-of-care treatment for PKU for decades. However, the diet is very hard to adhere to, given even fruits and vegetables contain protein; it does not address the underlying genetic defect of the disease; and limiting Phe does not help with the conversion of Phe to the needed downstream amino acids.

For school, Ava and her mom had to educate the staff about PKU. They explained that Ava does not have an allergy, and that if she ate too much protein, she would not have an acute reaction or go into anaphylactic shock. However, if a person with PKU has too much Phe, it could cause a host of symptoms including anxiety, depression and difficulty concentrating. Sharla says, “It doesn’t really hit people until they ask what happens if she has too much protein. Once you say, ‘brain damage,’ then it clicks with them a little more.”

By limiting Phe, a person with PKU is also limiting protein, which is essential for the body to develop and function properly, so medical foods and special Phe-free formulas are required. Sharla explained that while some insurance companies will pay for these needs, she has had to sit on the phone for hours to ensure coverage for the medically necessary food.

As Ava has gotten older, she has chosen to focus on the positives in her life. Her advice to others with PKU is to consider perspective. She says, “Don’t focus on the things you can’t [eat] because if you focus on the things you can’t eat, you’ll just be more sad. If you think about the things you can have, that will help with your PKU mindset.”

For those who meet someone with PKU, Ava suggests asking questions because PKU is more complex that it sounds initially. “I wish more people would ask so that I could help them understand.”

Ava and her mom have both found support from the PKU and metabolic disease community. Sharla is an active member of the Intermountain PKU and Allied Disorders group, and she attributes the leaders there with providing her with information when Ava was younger. She says, “It’s a very close community, and they really try to support one another, so that was very helpful.”

Ava and her mom