We all inherit traits from our parents through DNA, such as hair color or eye color. Our DNA carries all the information about how we will look and how our bodies will grow and work. All of that information is carried on parts of our DNA called genes. We have 2 copies of every gene: 1 from our mother and 1 from our father. When we inherit a gene that doesn’t work right, it can cause health problems like a UCD.
Urea cycle disorders (UCDs) can be passed down when one or both parents pass a copy of a gene that doesn’t work right on to their child. The most common type of UCD is called ornithine transcarbamylase deficiency or OTC deficiency. OTC deficiency is an X-linked condition. This means it is usually passed on from a mother to her child on her X chromosome. In rare cases, OTC can also be passed down from a father to his daughter.
Hear Rameses share his story about his daughters UCD diagnoses.Read transcript
My name is Rameses, and this is my story…I have a beautiful wife…we have six children between us. Out of those first three daughters, Mykah and Moriah are OTC patients.
Our daughter was born. And honestly, it was just like the third daughter in the line, so I thought easy-peasy. I’ve done this twice before. After about three to four days of hospitalization after birth, we went home with our baby girl. Again, I felt like a seasoned father at this point, so I wasn’t expecting anything out of the ordinary.
But it wasn’t hardly 2 months after birth, Moriah began to projectile vomit. That was the very first sign I knew something was wrong, but I didn’t know what it was… and once I gave her…the typical normal bottle of her formula, within seconds, literally, she, I didn’t even know the terminology at the time, honestly. But I found out later it was called projectile vomiting. I just saw it shoot out of her mouth like a water hose. And I couldn’t…I’d never seen anything like that before, ever. I knew I didn’t overfeed her. I’ve done this so many times before.
So, we began to talk to the pediatrician and, just to fast-forward the story, it took about 2 months of having our daughter basically regurgitate her meals.
We finally got that call from the pediatrician to get our daughter admitted. We got checked in in the evening.
6 o‘clock the next morning, ah, Moriah’s had a seizure. And I was really scared at that point.
We waited in the lobby area for a while, and then we were called by the doctors to come, come back.
They literally told us that she has a rare metabolic condition. It’s called ornithine transcarbamylase deficiency. I think it took me a while to learn how to pronounce it, actually. But they said it’s a life-threatening condition. That’s the thing that stood out the most.
I have two daughters with OTC deficiency. Moriah happened at 2 to 4 months of age. But Mykah’s diagnosis, my oldest daughter, didn’t come about until she was about 8 to 9 years of age. We’re actually going to a metabolic physician at that point in time and Mykah came into the appointment with her mother and began to talk to the doctor about headaches.
She was having pretty periodic headaches, almost a daily thing for her.
One thing I did notice about Mykah early on, probably around the age of 5 or 6, is she began to kind of avoid and pull away from meats. You know, where she would get a Happy Meal with chicken nuggets at one point in time, now, she just wants the fries. I thought that was a little peculiar, too. But, hey, kids change their tastes all the time.
But the doctor was like, no, let’s do a DNA test.
And so, we, actually, they tested the whole family.
And when the DNA test came back, after, I think it was a couple weeks or so, I was pretty shocked. That’s when the doctor called us back in with the confirmation. That Mykah was also an OTC patient.
And from that point onward, Mykah began her journey with OTC, ornithine transcarbamylase deficiency, and taking her medicines.
Our family, we, you know, need the help of medical professionals to manage the care of our daughters…that team consists of a myriad of people. But in short, it’s basically, we have a wonderful metabolic physician…who, may help to kind of spearhead and manage…and direct the care for both of my daughters. He, he manages both of them, and has for a number of years now.
And that also encompasses a metabolic dietitian that I work very, very closely with, and just really, just, can’t say enough wonderful things about these two individuals. They really have helped make our journey a lot easier in the last few years. We also have a metabolic nurse that I can rely on and reach out to. And she helps and supports us in whatever way necessary as well. And, of course, there’s other staff members in that team. Those are the core three really. The metabolic geneticist, our dietitian and then our metabolic RN. They all work together in unison with me to help manage, especially Moriah’s care, but Mykah’s as well.
The encouragement that I would give you is that it, it’s going to get better.
So just be encouraged to know that you’re not alone. You are in a very strong community. It’s only getting stronger.
A carrier is a person who has 1 normal copy of a gene and 1 copy that does not work right. Genetic testing can discover if a person is or isn’t a carrier and determine the chances of passing on a UCD gene.
With OTC deficiency, one parent (typically the mother) passes on the gene that doesn't work right via the X chromosome
- Men who inherit the gene that doesn’t work right will very likely have symptoms. Women who inherit the gene may or may not have symptoms. They are often called "carriers" and can pass it on to their children
Both parents pass on a copy of the gene that doesn't work right via any chromosome other than the X or Y chromosomes
- People who inherit two copies of the gene that causes an autosomal recessive urea cycle disorder will have UCD symptoms
Also called "de novo", a mutation that happened for the first time when the cells were forming, creating a gene that doesn't work right and causes a urea cycle disorder
Urea cycle disorder subtypes
Different genes cause different types of UCDs. There are 8 different types of UCDs, often called "subtypes":
- Ornithine transcarbamylase deficiency (OTC) — the most common UCD
- Carbamoyl phosphate synthetase 1 (CPS1) Deficiency
- Citrullinemia I (CTLN1)
- Argininosuccinate lyase (ASL)
- Arginase deficiency (hyperargininemia, ARG)
- Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome
- Citrullinemia II (CTLN2)
- N-acetylglutamate synthase (NAGS) deficiency
The name of the subtype tells you which enzyme or transporter in the urea cycle doesn’t work. For example, if you have ornithine transcarbamylase deficiency, it means your ornithine transcarbamylase enzyme is missing or not working.