Propionic Acidemia Explained

Ever had that moment when you feel like you're living someone else's life? An out of body experience , or a watching a show moment. Trying to figure out when you got here, how you got here, and what if this was all a dream? I had one of those today. I was listening to a knowledgeable woman speak about liver health and how she wondered how, with all the toxins around in our environments, a persons liver manages to function at all. I leaned over and whispered to my friend next to me "not all of them do". You see, we were friends with a family who had a child with a liver that didn't have all its functions working. They were waiting on a liver for a transplant for their child...

Two minutes it took me to realise that this was my life. That family was mine, the child was mine. Honest to god I could have sworn I was someone else in that moment. That I wasn't living this life waiting for a liver and living with a child with PA.

Most of those reading this will have a connection to us so know a little about Harry, Richard and myself, but just in case a brief introduction. I have a son called Harrison who is 20 months old and has a condition called Propionic Acidemia (PA). Harry's condition was diagnosed at 2 days old. My name is Anna and I am lucky enough to be his mum. Harry lives with me and his dad Richard.

This second attempt at a blog post is to try to explain a very complex condition in a way that most audiences will understand but still does it justice.

99% of the general population have never heard of PA. Even most medical practitioners have to look it up unless working in specialised hospitals.

Propionic Acidemia

Our body is a miraculous piece of art. All the functions that make up a human body are truly unbelievable. Once you start to appreciate what our body does you start believing in a higher power and in science as one. There is no other explanation for what we humans can do. I want to talk about a particular function though, one in the liver.

We all produce a number of enzymes that break down food into chemicals our body can use or when in excess, get rid of. Propionic Acidemia is a condition when one of these enzymes that we need does not get produced, due to a missing link in the patient’s DNA. The enzyme that is missing in a PA sufferer’s body is one that helps break down protein (and some fats). So a PA’s body can’t get rid of some of the excess protein by-products (propionic acid) and they circulate in the blood causing damage.

That is in its most simple form. There are many implications of this toxic substance, it usually affects the brain first as well as other organs such as the kidneys. The hardest, very very difficult thing to control, is the ongoing cumulative nature of this build-up of propionic acid. Even with the tightest controls on his diet and health, it is constantly building this acid in Harry's body causing damage the whole time.

There are a couple of cool links here if you want a more detailed explanation, the first link even has some great diagrams.

Medical Food publication

MDDA Website

Rare Diseases Website - Very detailed

Treatments

At the date of this post, there is no cure for Propionic Acidemia.

At the moment the management of Propionic Acidemia is mainly through diet (and a naturally occurring medicine called carnitine). If you can keep the protein level at just the right amount the body needs, it doesn't need to get rid of any. The problem with this is we can only ever guess how much the body needs. And of course, everyone is different! Too little protein can affect development, growth, hair, skin, eyesight..... the list is long. So Harry getting too little protein is nearly as dangerous as him getting too much.

The other challenge to this is our metabolism speed i.e. the speed in which our body turns food into usable chemicals. When we're hot, stressed, sick, exercising or even over excited, our body's processes speed up, needing more energy. If it can't find the energy from food, it takes the energy from our 'stores', these 'stores' are made up of protein. So the body takes our stores, uses it for energy, but our lovely Harry in this situation is not in a good way because his body can't get rid of the protein by-products that is attached to our stores, so the toxic propionic acid stays floating in his blood stream.

This is why sickness is dangerous in particular. I imagine when you're sick you don't much feel like eating, so instead your body uses the energy from its stores to fight the bugs. As I said, for Harry this is dangerous. So instead, with Harry, we have to make sure that his body can get the energy from low protein food instead so his body can handle the illness without the toxic side effects. But most of the time your body starts fighting the bugs before you show any symptoms, so picking up that change for our baby is important.

It has only been in the last 5 or so years that they have started using liver transplants as a way to treat PA. As the liver is where a large bulk of the enzyme is produced normally, the theory is you get a working liver, the new liver produces the enzyme to break down the protein correctly. It has had great success in PA patients. Although, much like hormones and other body functions the brain, kidneys and stomach have a lot to do with the production of this missing enzyme so although the liver transplant greatly improves the lives of those with PA, it is certainly not a cure.

Future State:

There are a number of things in the pipeline for PA, most promising being Gene Therapy. This would be life-changing, the biggest bonus being it wouldn't have the side effects of a liver transplant or the life time consequences of being on immunosuppressants, but Harry was born about 5 years too early. Waiting is too greater risk. I think i'll do a post on Gene Therapy, its utterly fascinating and definitely the future of medicine.

There is also an exciting medicine going to trial at the moment that gets rid of the excess propionic acid. This will be used instead of, or after transplant to mop up any extra nasties.

How you get Propionic Acidemia

Propionic Acidemia is a genetic condition. It only rears its ugly head when the two biological parents have recessive genes that are both inherited by the child. Year 9 biology at its basic.

Two carriers of this recessive gene have a 25% chance of having a child with PA. And the occurrence of PA turning up is about 1: 100,000. I'm sure there are couples out there who carry the genes and have just been lucky enough to hit the 75% every time.

The other part to this is that different mutations within your DNA could cause PA.

So Mum might have Mutation A, Dad might have mutation Z, both of these causing PA.

I hope the below diagram helps for those who don't 100% understand how this genetic inheritance works. You can find similar explanations by googling "genetics recessive traits".

Prognosis

Oh yes. I see the giant elephant. It's blue. And will.not.leave. Very rarely spoken of. It also changes. Constantly.

In the early days of Harry's diagnosis I refused to google it, instead leaving that to my husband and family. For me I needed to focus on doing what I could in that moment for my child. I don't know if it was the healthy thing to do, but there was no other option to get through. Pumping breastmilk, singing, reading and talking to him. Sleeping so I could repeat this. The extent of my planning was my outfit choice. Simple survival actions and thoughts. I needed to block most things out to just survive each day. And focus 110% of everything I had left to him. The battle that was to come, I didn't have anything left to give to that. So that was left for later.

As time has gone on I have found the reserve to find out what I can (with help). But one thing to this day I refuse to look into, or really acknowledge, is long term prognoses. There are two reasons for this:

1. The treatment for PA changes all. the. time. We learn more about the condition, the treatments get better, we learn more about how the human body works, it's a moving target. Things that were true 5 years ago are no longer true now in the treatment of PA.

2. Every kid is different. PA seems to treat each child differently. On top of that the environment a child is raised in has impacts too, country they were born into, distance from a hospital, access to information.

I'll leave the googling up to you but always take note the date on the research you find. It may be outdated.

I hope this has helped. There are so many different aspects to this condition. It would take me days to explain in detail. I should also note that this is my view of PA. A physician might tell you a different story, as would another parent with a PA child.