Novel therapies for Propionic acidemia – update Sept. 2018

Novel therapies for Propionic acidemia

Nicola Brunetti-Pierri, MD, Fondazione Telethon, Italy

This proposal was focused on the characterization of a fish model of propionic acidemia (PA) and on the development of novel therapies. The PA medaka fish model was found to recapitulate several clinical and biochemical features of the human disease, including reduced survival and locomotor activity, hepatic lipid accumulation, increased propionylcarnitine, methylcitrate, and propionate. Moreover, PA fishes showed better survival when fed with low-protein diet.

To gain insight into the disease pathogenesis and to search for potentially novel therapeutic targets, we performed an unbiased 3’-mRNA-Seq and NMR-based metabolome analyses. Both analyses showed global differences between PA and wild-type (wt) medaka. Interestingly, metabolism of glycine and serine resulted affected both at transcriptional and metabolites level and further studies are ongoing to investigate the role of these changes in the disease pathogenesis. Moreover, we found a marked increase in protein propionylation in PA fishes compared to wt controls. Protein propionylation is a post-translational modification occurring under normal conditions but its physiological role is unknown. Like protein acetylation, it is likely involved in regulation of gene expression, protein-protein interactions, and enzyme function. Interestingly, NAD-dependent sirtuins that are responsible of deacetylation of multiple proteins and have also de-propionylating activity, were significantly reduced in PA fishes. We speculated that aberrant protein propionylation in PA is toxic and proteomic studies are ongoing to reveal proteins with aberrant propionylation. With the support of this grant several drug candidates have been also investigated with the goal of developing new pharmacological approaches for PA.

In conclusion, we performed extensive phenotyping of the PA fish model that can be useful to unravel novel disease mechanisms and therapeutic targets.

updated September 2018

PAF Awards grant for Dr. Oleg Shchelochkov and Dr. Charles P. Venditti for $32,912

PAF awarded a  $32,912 research grant to Oleg Shchelochkov, M.D. and Charles P. Venditti MD, PhD at National Human Genome Research Institute, National Institutes of Health  – 2018

“Diversion of Isoleucine and Valine Oxidative Pathway to Reduce the Propionogenic Load in Propionic Acidemia.”

Patients with propionic acidemia require lifelong protein restriction. In addition to taking a protein restricted diet, many propionic acidemia patients are also prescribed medical formulas. This dietary approach aims to decrease the intake of four amino acids that can become propionic acid. These four amino acids – isoleucine, valine, threonine, and methionine – are called essential, because they cannot be made in the human body and need to be supplied from foods. Too much protein intake creates a situation where excess can lead to a buildup of propionic acid in the body. On the other hand, limiting these four amino acids too much can lead to poor growth. Therefore, patients’ diets are optimized to minimize propionic acid production while encouraging good growth. We wonder whether it is possible to increase dietary protein intake while minimizing the risk of propionic acid buildup.

To answer this question, we are planning to do a series of experiments in zebrafish. Why use zebrafish? Zebrafish share significant similarity to humans in how they process propionic acid. In addition, zebrafish reproduce and mature quickly, which are very important qualities to help search for new drugs that could be used to treat propionic acidemia. Our zebrafish are kept in a special building where the animals are being cared for by a dedicated team that includes scientists, veterinarians, engineers, aquatic specialists, and many others. They check on fish and feed them several times a day, maintain fish tanks, and keep their water very clean.

This type of facility is unique and had enabled our studies of metabolic diseases in zebrafish. Our ongoing studies have shown that zebrafish affected by metabolic diseases have symptoms that are very similar to patients. Even with treatment, affected fish have difficulty growing, get tired easily, have poor appetites and sometimes perish before adulthood. Using special genomic tools, we are planning to change in how the fish processes protein to direct it away from becoming propionic acid. As we make these changes to the biochemical pathways of propionic acidemia zebrafish, we will be carefully watching how these treatments improve their growth, development, appetite and survival. These experiments will help us understand how we can potentially reduce propionic acid toxicity while helping patients achieve a less restrictive diet.

Interview with Joel Pardo  – Summer  2020

Can you tell me about yourself and how you became interested in science?

I was always interested in the sciences. I think ultimately what propelled me towards a career in science was my research experience at the University of California, San Diego. The mentorship I received from Dr. Joshua Bloomekatz helped me develop the ability to reason scientifically and appreciate the opportunities to grow professionally. I learned from him how to design experiments to answer important scientific questions. We often had lengthy discussions about the direction of my project. He helped me make sense of the collection of observations coming from different sources and nurtured my own independent thinking.In gaining an appreciation for his analytical method of thinking, I began to see myself as someday contributing to scientific thinking as a physician-scientist.

During your training at NIH, you worked on a project to find new treatments using zebrafish. What did you find exciting and challenging about studying zebrafish?

Most people are familiar with mice, which are often used in science to find and test new drugs. Working with mice requires a lot of work to have enough animals needed for an experiment. Zebrafish, on the other hand, can produce hundreds of offspring after one breeding cycle. Zebrafish lay eggs directly into water, which also makes it easier to study them soon after they hatch. Somewhat surprisingly,the zebrafish enzymes that handle propionic acid are very similar to the enzymes in humans. These two properties of zebrafish make them an exciting model to study a disease like propionic acidemia.

One of the most challenging parts of my research in zebrafish was their size. Zebrafish offspring are very small, measuring less than a quarter of an inch. I had to spend a lot of time looking at zebrafish under the microscope and learn how to move them around without hurting them. This can be difficult as these small animals are fragile at this young age.

Can you tell us about your PA project?

Earlier in my work, we were able to get zebrafish, which had mutations in the genes linked to propionic acidemia. I needed to understand what propionic acidemia does to zebrafish. We were able to show that propionic acidemia in zebrafish looks a lot like the disease we see in patients. Fish with propionic acidemia had poor appetite, did not grow well, and had difficulty moving. Using special genetic tools, we then attempted to change how zebrafish processed propionic acid and helped them survive longer. Our preliminary results are proving promising, but more work is still needed.

What are your plans after you complete your training at NIH?

The NIH postbac program is a full-time research award for students that have recently completed a bachelor’s degree and are considering a career in science or medicine. I was fortunate enough to join Dr. Charles Venditti’s lab 2 years ago to work on the zebrafish project under Dr. Oleg Shchelochkov. I thoroughly enjoyed my post-bac experience. Looking back on the past 2 years, I feel the lab, and in particular the mentorship of Dr. Shchelochkov, has facilitated and nurtured my growth as a future physician-scientist with roots in propionic acidemia research. In 2019 I applied to MD/PhD programs at several US universities. After having traveled to over half a dozen states and interviewing at many fantastic universities, I ultimately decided upon the physician-scientist training program at University of Minnesota. As I plan my transition to the program, I am currently looking for winter coats.


Liver Transplantation for Propionic Acidemia: FAQ

Liver Transplantation for Propionic Acidemia:

Part 1 – Answers to Questions that Families May Have

James Squires, MD, MS

Dr. James Squires

Dr. Squires is a liver disease specialist at Children’s Hospital of Pittsburgh of UPMC and an assistant professor of pediatrics at the University of Pittsburgh School of Medicine.

Jodie M. Vento, MGC, LCGC

Jodie Vento is a genetic counselor and manager of the Center for Rare Disease Therapy at the Children’s Hospital of Pittsburgh of UPMC.

What can we expect that a liver transplant could do for our child?

Based on experience to date with liver transplants in children with Propionic Acidemia (PA),we can say that after a liver transplant,children are likely to have a substantially better quality of life and a dramatic reduction in metabolic crises. It’s important for families to understand, however, that liver transplantation is not a cure for PA. This is because the enzyme deficiency that causes PA exists throughout the body, not just in the liver.

The liver transplant serves as what we liver specialists call a bulk enzyme replacement, providing enough functional enzyme to minimize – if not eliminate –metabolic crises, which are the most severe complications of PA for affected children as well as one of the most frightening features of the disease for families.

Because complications related to PA may still occur following a transplant, there will be a continued need for your child to get follow-up care with one or more medical specialists.


Is there a minimum or “best” age for a child with PA to have a liver transplant?

There is no minimum or “best” age. At our center, the average age of a liver transplant for a child with PA is about seven years old, but we have performed transplants in children as young as one year old.

The best time to consider a liver transplant is while the symptoms of PA are still reasonably well controlled. There is also no minimum age for undergoing a pre-transplant evaluation or being placed on the transplant waiting list.

What should we consider when deciding where to take our child for a liver transplant evaluation?

The most important factor to consider is the experience of the surgical team performing liver transplants in patients with PA and other metabolic diseases. These patients have complex needs that are different from those of patients receiving liver transplants for other conditions.

The pediatric liver transplantation program at Children’s Hospital of Pittsburgh of UPMC was established in 1981 by world-renowned transplant surgeon Thomas E. Starzl, MD, PhD. Our t Director of Pediatric Transplantation, George Mazariegos, MD, FACS, pioneered liver transplantation for children with metabolic diseases in 2004. Since that time, Children’s Hospital has performed more than 330 liver transplants for children with metabolic disease,more than any other transplant center.

We’ve also performed more liver transplants in children than any other center in the United States and more living-donor transplants than any other pediatric center in the country. Our one-year survival rate for pediatric liver transplant patients is 98%, exceeding the national average of 95%, according to the Scientific Registry of Transplant Recipients, Jan. 2018 release.

In addition to our world-renowned and experienced liver transplant surgeons, our Center for Rare Disease Therapy includes international experts in the diagnosis and treatment of PA and other metabolic diseases.

How would we start the process of having our child evaluated for a liver transplant?

I can tell you how the process works here at Children’s Hospital of Pittsburgh of UPMC. It starts with a referral from your doctor or hospital requesting that we evaluate your child. We also receive self-referrals directly from interested families. We will ask the doctor or hospital, or both, to send us all of your child’s medical records.

We will look at the records carefully to help us understand your child’s medical history and current situation. This information helps our multidisciplinary team develop an individualized plan for your child’s evaluation visit. For example, if your child has recently had certain laboratory or imaging tests done, we won’t repeat those tests unless there’s a valid medical reason for doing so. Understanding how the disease is affecting your child helps us identify which specialists your child should see during the evaluation.

It’s important for families to know that undergoing a pre-transplant evaluation involves no commitment on either side. It carries no guarantee that your child will be listed for a transplant or, conversely, any requirement that you must agree to have your child placed on the transplant waiting list. We can answer questions, provide information, and make recommendations. Ultimately, however, the decision to proceed with a transplant, or not, is a personal one for each family to make.

The evaluation is an opportunity for the family and the health care team to meet and get to know each other, as well as for the family to gather information and get answers to any and all questions you may have. We hope you’ll feel comfortable raising any concerns. Please don’t hesitate to ask us about any issue that’s on your mind. There are no dumb or silly questions. And, of course, if after you’ve gone home you think of something that you wish you had asked, please give us a call.

You can expect that the evaluation will be a two- or three-day event. The staff of our Center for Rare Disease Therapy will work with you to arrange for you, your child, and other family members to stay near the hospital, either at our Ronald McDonald house or at a nearby hotel, while you’re here for the evaluation.

We’ll send you a schedule in advance of your visit. This will tell you which medical and surgical specialists you’ll be seeing at what times and what laboratory or imaging tests we would like your child to have during the evaluation. To the extent possible, we try to anticipate all the testing we’ll need so that it’s a relatively smooth process while you’re here.

Please tell us more about what we can expect during our child’s evaluation.

Because PA is a genetic disease, the specialists you’ll see will likely include a medical geneticist and a metabolic dietician. Also, because PA often causes heart problems, your child’s evaluation is likely to include basic heart function tests and an assessment by a cardiologist. Depending on how the disease is affecting your child, the evaluation may also include visits with specialists such as the following:

  •         A neurologist, to assess brain function
  •         A gastroenterologist, to assess pancreas function
  •         A hematologist, to assess bone marrow function

Although we try to anticipate all the testing we’ll need and schedule it in advance, sometimes we may decide that it would be helpful to do an additional test that wasn’t originally on the schedule. For example, depending on the results of the basic heart function tests, the cardiologist might want to do a “stress test” that will provide more detailed information and measurements relating to how well your child’s heart is functioning.


If we decide to go ahead with listing our child for a transplant, what are our options for obtaining a donor liver? How long can we expect it to take to find a compatible donor?

PA is considered a high-priority condition for liver transplantation, so your child’s name will be near the top of the waiting list. However, because demand for donor livers is high and supply is limited, I tell families to be prepared to be on the waiting list for several months.

With any liver transplant, careful testing needs to be done to ensure compatibility of the donor liver and the transplant recipient.Many factors can influence the waiting time for a compatible organ. For example, a child with an uncommon blood type may face a longer wait.

In general, child-size donor livers are scarce. A unique feature of the liver, however, is that it is the only organ in the human body that can regrow. This means that in some cases it’s possible to transplant a section of a healthy liver rather than the whole organ. For example, a child who needs a liver transplant may receive a section of a liver from an adult donor. You may hear this type of transplant referred to as a “reduced-size” or “split” liver transplant.

Another type of liver transplant involves a living person – such as a relative, friend, or even a stranger – donating a section of their liver to someone who needs a transplant. Living-donor transplants may be an option for some children with PA. However, because PA is a genetic disease, parents and possibly siblings may be carriers of one of the genetic defects that cause the disease. Someone who is a carrier would not be a suitable living donor.

The good news is that children who receive a partial liver seem to do just as well as those who receive a whole liver. All of the options for obtaining a donor liver, including a reduced-size, split, or living-donor transplant, are discussed during the pre-transplant evaluation.

We’ve decided that a liver transplant is right for our child. What are the next steps?

When your child’s name is placed on the liver transplant waiting list, we will give you a pager that you will need to take with you everywhere you go so that we can reach you right away when we get a call that a matching donor liver is available. We don’t know when that call will come, but when it does you’ll need to be able to get to Children’s Hospital in a safe, but timely fashion. The transplant team will work with you to establish a ‘travel plan’ for you and your family for when the transplant is likely to occur.

While your child is on the waiting list, our specialists will work with your local doctors to care for your child and optimize their medical condition ahead of the transplant.

We know that waiting can be a difficult time for families. Your transplant coordinator is always available to respond to your questions and concerns and can also help you make travel arrangements.

Once you arrive at the hospital, preparations for the transplant may take from 12 to 24 hours. Your child will undergo another round of tests to confirm that the donor liver is a good match. Your child will also need to fast before surgery. Our metabolic dieticians will help us prepare intravenous fluids to provide your child with an individualized balance of fats, protein, and glucose to maintain stability while they can’t take anything by mouth.

The liver transplantation surgery may take up to several hours, although this varies in each case. While your child is in the operating room, a member of the transplant team will keep you informed on the progress of the transplant.

After the surgery, your child will go to the intensive care unit to be monitored closely until their condition is stable. Then your child will be moved to the liver transplant unit. Staff here will help you learn about your child’s medications, diet, need for follow-up care, and anything else you’ll need to know to care for your child.

After the transplant, will our child have to take anti-rejection medication?

After a liver transplant, you should expect that your child will need to take medication for the rest of his or her life to prevent organ rejection. The body’s normal reaction to a transplanted organ is to recognize it as a “foreign agent” and mount an immune response against the new liver. Anti-rejection medications suppress the immune system, which is the body’s defense system against illness and infection, to prevent it from attacking the new liver.

Because anti-rejection medications weaken the immune system, your child may be more likely to get infections – and those infections will be harder to treat. You will need to notify the transplant team at the first sign of an infection, such as a fever, chills, sweats, coughing, nasal congestion, diarrhea, redness or swelling, pain, or vomiting. A referral to a doctor may be needed as well.

With immune-suppressing medications, the goal is to find a treatment plan that achieves the needed degree of immune suppression while causing the fewest and least harmful side effects. Regular blood tests will help your child’s doctors monitor the medications’ effectiveness.

The risk of organ rejection declines over time. This means that in time your child should be able to take lower doses of anti-rejection medications. Most likely, however, he or she will need to continue taking at least a low dose of immune-suppressing medication lifelong.

Here at Children’s Hospital of Pittsburgh of UPMC and elsewhere, research is underway to learn more about whether some liver transplants patients can eventually stop taking immune-suppressing medication without increasing their risk for rejection of the transplanted organ. This research is a long-term effort, however, and it will be years before we can answer this question.

For more information, please visit: or call (412) 692-RARE (7273)

In Part 2 of this article, Dr. Squires will summarize the findings of a recent study of outcomes in children with PA and methylmalonic acidemia who received liver transplants at Children’s Hospital of Pittsburgh of UPMC.

Bryan K.’s Story

Bryan’s Story

Updated in 4/2022 in the Spring Newsletter

Hello everyone. I am 35 years old and I have Propionic Acidemia. Life with Propionic Acidemia is not always easy. I was diagnosed late which caused me to have a stroke at a very young age. After years of a wheelchair and walker I made a somewhat normal recovery.

Around 2012 a few days after one my kickboxing classes. I noticed my knee was swollen. I had thought it was from my kickboxing class but turns it was Lyme disease. Something that greatly affects me today. I get flair ups where my ammonia levels skyrocket, I get incredibly fatigued, and my muscles get pain that I can’t describe.

In 2015 I was having the weekend of my life at my brother’s campground until I woke up in the ICU that is. I decided to throw caution at the wind and tried my hand at alcohol. It led to me having metabolic acidosis. I was lucky not to suffer any suffer serious side effects.

That’s the thing between the Propionic Acidemia and Lyme disease you just never know what could happen! On top of my health issues I still have to deal with other real life events. Things like my parents getting divorced, the passing of my grandfather, and Covid-19.

I’ve always been into doing mindful things such as yoga and taking care of myself in general. However, it wasn’t until my parents’ relationship started to get worse that I found mindfulness meditation.  Even though I saw the writing on wall, it deeply saddled me.

I remember stumbling upon Rebekah Borucki (BEXLIFE) on YouTube. She was a meditation teacher. My favorite Mantra of hers was “I am like a boat on the ocean. My thoughts they rock me just a bit, but they never carry me away. I am anchored in the here and now!” There was something about that saying that just put my mind at ease.

From that point on I became obsessed with how the mind works and the benefits of mindfulness meditation. I learned that once you realize that all you can control is yourself, your reaction, emotions and that happiness is a choice. It’s only then will you find inner peace.

Fast forward to 2020, I had been stuck with a job that I was content with not happy with. I was working as a cashier at a food store which for me was physically exhausting. Then what turned into somewhat of a blessing, the virus hit. I knew that with my health issues retail was no longer an option for me.

Instead of going though depression and anxiety over virus I decided to continue my mindfulness journey. After taking multiple classes on mindfulness and meditation I couldn’t explain to you how much it changes your life! No longer do I stress about things I can’t not control. I now own mindfulness routine that consists of nature walk, yoga and meditation. I can honestly say that I enjoy life to fullest. Moment by Moment.

Check out my website at and my facebook group “Be Present Lifestyle”


Hello for those of you don’t know me, my name is Bryan. I am 31 years old. I was born with Propionic Acidemia.Bryan  In the beginning doctors did not think anything was wrong with me. They told my mom I was just a sleepy baby but my mom knew that something was wrong. I was officially diagnosed at Saint Cristopher’s hospital when I was only a few months old. Shortly after I would start being seen at Children’s hospital of Philadelphia.

When I was really young I suffered a metabolic stroke and was in a comma for four days. The doctors said I would never walk or talk. That was not an option for me. Remembering the days of the wheelchair, walker and speech classes reminds me to be thankful for where I am at today. I am able to walk and talk just fine. However Propionic Acidemia has it ‘s effects on me. Until the age of 24 I had a feeding tube  for drinking a special formula called Propimex – 2! Today I am able to drink it by mouth. What I like to do is mix it with two cups of whole milk with strawberry syrup. From my Propionic Acidemia I also suffer from Cardiomyopathy which effects my hart. I’m taking carvedilol 25 mg to keep it under control. I was originally on Lisinopril then I learn that it can be harmful to your kindney’s. (Important to know)

My chronic kidney disease which was not found by metabolic doctor but believed to caused by my Propionic Acidemia is at stage three. The weird thing is normally with kidney diseases they only get worse, but mine has actually gotten better. One of the big things is to drink lots of water. I try my best to drink sixty four ounces of water a day.


Bryan KNow a day’s my health is really good. I work as a cashier at a food store but  dream is to public speaking. I have my own apartment and exercise daily cause I know how important it is for my muscles, mind and motor skills. I like yoga but anything you can do will help. I’m a picky eater but I am trying to teach myself to eat healthier. hope this article helps give people they can a somewhat normal life with Propionic Acidemia!

Check out my blog.



Partners in Progress: Families and Scientists Catalyze Research for Rare Diseases

“Partners in Progress:  Families and Scientists Catalyze Research for Rare Diseases”

On Nov. 15, 2017, Baylor College of Medicine and Texas Children’s Hospital hosted a panel discussion as part of theEvenings with Genetics seminar series held at the Children’s Museum of Houston. The topic was “Partners in Progress:  Families and Scientists Catalyze Research for Rare Diseases” and panelists traveled from both coasts and the center of the country. Panelists included Jill Chertow Franks, President, Propionic Acidemia Foundation; Cynthia Le Mons, Executive Director of the National Urea Cycle Disorder Foundation, Tracy Smith Hart, Chief Executive Officer, Osteogenesis Imperfecta Foundation and Brendan Lee, MD, PhD, Robert and Janice McNair Endowed Chair, Professor, Department of Molecular and Human Genetics, Baylor College of Medicine. These family/scientist partnerships are a new and exciting development in the research efforts for those impacted by rare diseases.

The audience of almost 80 people consisted of parent leaders, rare disease foundations, medical students, genetic counseling students, pharmaceutical companies and undergraduate biotech majors. Each panelist discussed the partnerships with rare disease organizations and scientists and their strategies for success in obtaining funding for research from the National Institutes of Health (NIH). In addition, panelists shared how they became involved in the rare disease organization and offered advice for other rare disease organizations as well as researchers with regards to working together to submit requests for funding. Dr. Brendan Lee discussed the positive impact of family/scientist partnerships and that these collaborations highly beneficial for progress in understanding rare disorders and developing effective therapies.

Susan D. Fernbach, RN, BSN

Director of Genetic Outreach

Director of Diversity and Community Engagement

Assistant Professor, Dept. Molecular and Human Genetics

Baylor College of Medicine/Texas Children’s Hospital

Christian M.

Christian M. – updated Febrary 2019

Christian M.

Christian M.

Christian, also known as CJ, is a fun loving five year old. He loves to listen to music, dance, and sing. His favorite activities include playing with his sister and watching YouTube videos. Christian is in full day kindergarten and loves socializing with his friends. Christian joined Yoga Club at school and he participates in gymnastics, tennis, magic classes, and horseback riding through the park district. He loves to travel and his favorite place to visit is the Great Smoky Mountains.

Christian’s older sister was diagnosed with Propionic Acidemia through the newborn prescreening, therefore we had a crisis management plan put in place for his birth. Within 48 hours of his birth, we received his diagnosis of PA. Currently, Christian eats 11 grams of protein, drinks Propimex-2, and take vitamins daily. We always seem to end up in the hospital during flu season, but other than that Christian has been a very happy and healthy little boy meeting all of his milestones.

Past story –  Christian – age 3


Christian M.

Christian, also known as CJ, is a three year old dancing machine. He loves to listen to music and have dance parties in our kitchen and basement. He is the life of the party and always making people smile. CJ attend preschool twice a week and is also involved in soccer and gymnastics. At home, he loves to follow his older sister around and try to play whatever she is playing. His superhero toys are often battling Barbies. Like most other three year olds, CJ loves cars, trucks, and his favorite television show is Paw Patrol.


Liver Transplant

Liver Transplant

There are many publications on liver transplantation for your review. The decision for families to have a liver transplant is a difficult one and is best discussed with your medical providers.

Family Experiences with Liver Transplants