MCADD - It's Genetic!

So I mentioned yesterday that LB has MCADD because his MCAD enzyme isn't working. What exactly causes that to happen? The answer is genetics. Your body has genes that tell it to make enzymes and his genes that make the MCAD enzyme are what isn't working.

Having errors in your genes isn't all that unusual. Our genetic counselor told us that everyone has errors in their genome, typically around 20. Genetic errors aren't usually problematic because you have two copies of each gene and most of the time, at least one of those copies is fine. The body uses the "good" copy to do what it needs to do. Unfortunately, BOTH of LB's genes that tell his body how to make MCAD either aren't there or are broken, so his body honestly doesn't know how to make the MCAD enzyme. It's kind of like his body's recipe book has that page ripped out or somebody spilled something all over it and it's illegible. As much as he may want to make that enzyme, he just doesn't know how.

How did he end up with two bad copies of the same gene? It's his parents' fault!!  Husband and I just happen to have the same errors in our genetic code and we both passed the "bad" copy of the MCAD gene onto LB. It's likely that Husband and I are both just carriers of the condition. We have one good copy of the MCAD gene and one bad copy, but our bodies can use the good copy to make the enzyme and we are fine. Unfortunately, between the two of us, we didn't give LB a single good copy to work with. With both of us being carriers, the chances of us having a baby with MCADD are 1 in 4. The process looks something like this...

We know through newborn screening that LB has MCADD. That is, he has two bad copies of the gene. We now know that both Husband and I are at least carriers of the condition (Rr) since we produced offspring with one bad copy from each of us (rr). If we are both carriers, then there is a chance that our older son, LM, may also have inherited a copy of our bad gene. He could also be a carrier (Rr) and there is a 50% chance of that. The best case scenario would be that he inherited only our good gene (RR) and there is a 25% chance of that. Since the state was screening for MCADD two years ago when he was born, it is unlikely that the LM has MCADD, but they suggested we re-test him just to be sure -- his sample card may have been mishandled or the wrong test done on the wrong blood spot. Again, it is unlikely that he has it, but we're going to go for "better safe than sorry."

Our genetic counselor told us that in some situations, infant screening has identified the condition in a parent (since testing for it has been only relatively recent). With MCADD, the parent happens to be lucky enough to not have ever been very ill to where their life was in danger due to fasting, but knowing they have the condition going forward can be very helpful for future illnesses, surgeries, etc. Knowing that there is also a possibility that one or both of us could have MCADD (although unlikely), we are both going to be tested to be sure. If one of us ends up testing positive for MCADD, our genetic situation changes slightly...

If one of us were affected with MCADD, that person could only pass a bad copy of the gene onto our child. The unaffected parent could pass on either a good copy or a bad copy. Thus, this would give us a 50-50 chance of having a child with MCADD and all of our children would at least be carriers of the condition.

I doubt either of us has MCADD, but it's also so statistically rare that two people with the same genetic errors have children together, so I guess anything is possible. I'm still really thankful for newborn screening, though. Without it, we would never have known LB had this condition and we certainly wouldn't have know that we were carriers of it either.

MCADD Explained

As promised, here is a little more information about LB's medical condition, MCADD.

MCADD is a fatty acid oxidation disorder found in about 1 in 15,000 babies. Fatty acid oxidation is the process your body uses to turn fats into energy and fatty acid oxidation disorders occur when certain enzymes that break down these fats into energy are either missing or broken. In MCADD, the Medium Chain Acyl-CoA Dehydrogenase enzyme is affected and individuals with MCADD are unable to break down medium chain fats from foods they eat and are also unable to break down medium chain fats stored as body fat. The process looks something like this...

So, if the body can't use the fats, what does it do with them? Basically, it treats them as toxins. Our bodies have substances called carnitines that serve to get rid of waste products.  LB's body is going to end up making a lot of carnitines because not only will they have to get rid of all the "normal" toxins that our bodies need to get rid of, they also have to get rid of the fats that he can't metabolize into energy that his body "thinks" are toxins. The doctors will monitor his carnitine levels periodically and may need to supplement his carnitine levels if he's not making enough.

MCADD can cause bouts of illness called Metabolic Crisis which can include sleepiness, irritability and poor appetite. These can be followed by fever, diarrhea, vomiting and hypoglycemia. Anytime that he is losing nutrients and unable to replenish them, he is in trouble and needs to go to the hospital for a glucose IV, which is, in essence, readily accessible energy for his body to sustain metabolism. If he is not treated quickly for metabolic crisis, he can have breathing problems, seizures and possibly even slip into a coma or die (scary!). Thankfully, metabolic crisis can be avoided simply by not allowing him to fast OR if he is fasting (because he can't keep food down due to illness, etc), we have a can of special formula to feed him. It is called polycose and is basically just pedialyte with HUGE amounts of sugar that his body can immediately use for energy, thus maintaining his metabolism.

Polycose Potion

It was a little more difficult to fill out prescription for Polycose than we anticipated.  Our pharmacy called us and said that they couldn't even order it.  We called the metabolic clinic at Children's hosptial and asked them if they could help.  Sure enough, the pharmacy on site at the Children's Hospital is a Walgreen's and our local pharmacy is also a Walgreen's.  Their pharmacy had it in stock, so they put their pharmacy in touch with ours and voila!  This lovely can of powder is now hanging out in our pantry.

Funny.  The first time they said "Polycose," I kept thinking about Harry Potter and his Polyjuice Potion.  

Metabolic Appointment

We met with the Metabolic Specialists at Children's Hospital this week. It was our first visit to a Children's Hospital and we were immediately in awe of how kid-focused everything was -- from the colorful waiting areas complete with toys to the little red wagons they use for transporting kids around.  We were anxious to hear more about the condition LB has and get complete information on how we would be able to keep him healthy.  I admit that I was a little bit scared of what we were going to hear.

The first thing they did was to weigh and measure LB and they were keen to note his weight in kilograms (for reasons I'll discuss later).  We then met with a genetic counselor who talked to us for more than an hour.  She took a complete genetic history of both my husband and me, in addition to educating us on how LB inherited MCADD and how the newborn screening system alerted them to contact us.  She then told us about MCADD and what we would need to be aware of to ensure that LB remains healthy.  More details on these in future posts...

Basically, we need to keep careful tabs on how much and how often he eats, especially during his first year.  His body cannot rely on stored fats for energy like that of a person with normal metabolism, so his body has to rely on glucose.  Right now, he is getting glucose from breast milk, but when he expends that energy, he has only a small store of glucose in his liver than he can rely on for back-up power.  As he grows, that store will grow larger and he will be able to go longer between feedings.  For now, the rule of thumb is that he can go one hour between feedings for every kilogram of body weight he has.  He is 3.375 kg now, so he can go about 3 hours between feedings. 

In times of illness, we need to be extra careful to monitor how much he is eating and how much he is keeping down.  If he vomits, for example, we would need to go back to his prior feeding and count the number of hours it has been since his last meal in order to accurately assess how often it has been since he last ate (and retained the food).  We were advised that they would likely have a very low threshold for simply admitting him to the hospital for IV fluids in times of illness so that they could be sure that he is getting the fluids that he needs to keep his body from going into metabolic crisis, the consequences of which can be devastating.  We were provided with an emergency letter to present to the Emergency Room staff which describes his condition and his need for immediate medical intervention to prevent life-threatening complications (it sounds very scary for a reason -- it's meant to scare the ER docs into treating him swiftly and aggressively, even if his illness seems minor on the surface because it's what's going on with his metabolism that is of concern and we can't observe that just by looking at him).

We were also given a prescription for Polycose, a glucose-rich powder that we will need to feed to him in times of illness to make sure that he's getting enough glucose to maintain his metabolism.  In a typical child, you would feed them pedialyte or gatorade to maintain their electrolyte balance in times of illness, but we were told never to feed LB straight pedialyte, only pedialyte that is doctored with his prescription polycose since pedialyte doesn't have any sugar, which he will desperately need when he is sick.

We asked if he would need a special diet and they told us he wouldn't.  He just needs to eat regularly and probably have a good, hearty bedtime snack once he's old enough to sleep through the night.  He doesn't have to avoid any foods or do anything special.

We asked if he would be able to do all the things that normal kids do -- play sports, etc. and they assured us that he would, as long as he eats well and avoids fasting.

We asked if the clinic treats a lot of kids with MCADD and they said that the state screening program has picked up approximately 20 kids since the screening program for MCADD began 6 years ago.  All of them are healthy and doing just fine, although they cautioned us that some parents of MCADD kids tend to over-feed their kids, which is unnecessary and can cause weight issues.

Unfortunately, they did relay a story to us that was quite sad.  Ironically, it was also one that I remember reading about while I was pregnant with LB.  A baby died when he was four-days-old and his newborn screening came back positive for MCADD the very next day.  The baby fell asleep in his mom's arms and never woke up.  His parents didn't know that he had MCADD and needed to eat frequently.  The hospital where he was born didn't courier their screening cards to the lab, there was a weekend involved and the end result was very tragic.  How very thankful we are that our newborn screening result came back so quickly.  I don't dare think about what would have happened to little LB if we hadn't gotten the call until Monday morning, instead of when we did -- late on a Friday night.

The clinic will see us every few months for his first year, since so much changes in kiddos during their first year.  After that, they will likely only see him about twice per year. 

By the Numbers

4 -- number of people in my family =)

10 -- number of days old LB is

8 -- number of doctor's appointments we've had in the last 7 days

24 -- number of pounds that I've lost since giving birth

16.5 -- LB's weight gain in ounces since leaving the hospital

12-14 -- average number of times per day that we feed LB

2.5 -- average amount of breastmilk per feeding

Gratitude

It has been a little over a week since our new baby was born and a little under a week since we found out about his metabolic condition.  In the midst of all the activity of the last few days, I am overwhelmed with gratitude.  I am truly thankful for so very many things...

1. The infant screening program in Colorado that includes an expanded panel of metabolic disorders, including MCADD. This expansion has only been in effect since 2006. Before that, parents of MCADD kids didn't know they had a problem until they became very gravely ill. Thank goodness for early identification. It saves lives!
2. Medical technology that allows disorders like this to be identified early in the first place.
3. The people at the infant screening lab who identified LB's abnormal results and started making phone calls, even though it was very late on a Friday night and they could very well have just gone home instead of taking action.
4. The staff at the metabolic clinic at Children's Hospital who declared this an urgent situation and mobilized all of their resources to find us on Friday night.
5. Our pediatrician who tracked us down during his Friday night to make sure LB was OK and to give us the information we needed to keep him safe.
6. The nursing assistant at the hospital who encouraged me to give LB just a few drops of formula when he was having trouble latching on Wednesday night. Knowing what we know now, in retrospect, that little bit of food in his tummy during the time that my milk wasn't in yet may very well have been life-saving.
7. The lactation consultants at the hospital who are helping me through some breastfeeding difficulties with LB to help ensure he gets the immunities provided by my breastmilk so that he can stay healthy.
8. The informative appointment with the metabolic clinic today (more on that later -- there's a lot of info to relay).
9. Having the nation's #5 ranked children's hospital right here in our backyard and having a direct line to a metabolic physician 24/7 in case we ever have an emergency.
10. My Mom, who has been cooking our meals and doing our dishes and washing our laundry and boiling bottles/nipples/pacifiers and keeping our older son entertained and sending me upstairs to take naps and giving me lots of hugs. I have no idea how we would have made it through this week without her here.
11. My husband, who has been chauffering us to a myriad of appointments all week, not to mention helping me in and out of the car (still recovering from the c-section), taking middle of the night feeding shifts and also regularly sending me to bed so that I can get some rest. You are my rock through all of this and I love you so much!
12. Our older son, who has been an awesomely loving and gentle big brother and who has been on his best behavior for his grandparents, despite the major upheaval in his world over the last week and a half. He's a real trooper.
13. My new baby - LB!  He is an absolute joy and an incredibly cooperative baby. He is an excellent eater (hooray!), a great sleeper and he has barely cried during all of the blood draws and doctor's appointments. Also a real trooper!
14. My quick recovery from the c-section. I am feeling great in record time. I can even put on my own shoes now.
15. All the prayers from family and friends that have supported us throughout the last week. We can feel them working.
16. All of the caring phone calls from the pediatrician and the metabolic clinic all week to check up on us and make sure LB is doing ok. Everyone is very focused on his health and well-being and I know that we will have all the medical support we could ever need if anything ever happens.
17. Being done with doctor's appointments for awhile. Other than my 2-week post-c-section check-up next week, our calendar is much more open from here on out. That leaves lots of time to snuggle at home with our boys and nothing could make me happier than that.
18. A week of lovely 70 degree weather that has allowed for easy travel to/from all of our appointments and ample opportunities for our older son to play outside (one of his favorite things to do).
19. Grandmas who sprung into action to buy us newborn clothes and diapers (our older son checked in at over 9 lbs and never wore newborn sizes...needless to say, we weren't expecting such a little guy this time around).
20. Not being scared anymore.  LB is going to be just fine.

Finding Out

Last night during dinner, Husband's phone rang and he excused himself from the table to answer it. I was only half hearing Husband's half of the conversation because of the conversations already underway at the dinner table with my Mom, Husband's parents and our older son, "LM." I gathered that it was someone in the medical profession that had called, but I assumed it was just the hospital phoning us with their discharge survey since they warned us that we would get a call in the next few days. At the point that I heard Husband ask "will he be able to live a long, normal healthy life?" my heart started to race. Something was wrong. Something was very wrong. I started to have trouble catching my breath and even though everyone else at the table continued talking, the only thing I could hear was Husband continuing this phone conversation in the hallway outside our kitchen.

The phone call was from our pediatrician's office.  "LB's" newborn screening had come back abnormal for a metabolic disorder called MCADD (Medium Chain Acyl-CoA Dehydrogenase Deficiency). It is a recessive genetic disorder where the MCAD enzyme is either missing or not working properly. The job of this enzyme is to break down medium chain fats. Since the enzyme doesn't work, medium chain fats cannot be broken down and the affected person cannot derive any energy from those foods/fats. This is problematic because energy from fats keeps us going when our bodies run low on their main source of energy (glucose) on occassions when we don't eat for a stretch of time (like when we miss a meal or when we sleep). In a person with MCAD, once the glucose is used up, there is no energy reserve in the form of fat and a metabolic crisis can occur.

The pediatrician was calling to check on LB's well-being, to make sure that my milk had come in, that he was eating regularly and to instruct us that he has to eat every 2-3 hours or he could become very very sick. He told us to come to the office when they opened at 9 a.m. and he would go over more of the specifics with us.

Needless to say, we were panicking. We were keeping track of when he ate already (force of habit since they make you do it at the hospital), but we were even more intent on monitoring his feedings now that we knew this. All through the night, we set our alarms and woke him every 2 hours to make him eat.

The doctor's appointment confirmed that he was gaining weight since he had left the hospital and provided us with some additional information on what our next steps would be.  LB would need to come back on Monday for his standard first visit to the pediatrician and for a blood draw that would help them to confirm the diagnosis from the newborn screening. We were told that sometimes if a newborn screening (done with drops of dried blood) came back abnormal, the follow up test (done on liquid blood) would come back just fine, but since LB's test results were 30 times the normal level, it was unlikely that this was a fluke. They were expecting a confirmation of the diagnosis. We would also need to schedule an appointment with the metabolic specialists at Children's Hospital to get further information on what we should be doing. For the time being, our main job was to make sure that he ate at least every 2-3 hours and if he went longer than 4 hours without eating to take him to an emergency room to get an IV.

We were also advised that we would have to watch him very closely when he gets sick so that he doesn't run out of energy due to vomiting, lack of eating, etc. The doctor actually said that in a way, LB would be easier to treat than an average child because with an average child, doctors always have to weigh the benefits of sending them to the ER for fluids to rehydrate versus using a wait and see approach at home with popsicles and pedialyte. With LB, there would be no threshold. He would be sent for fluids immediately. No questions. No delays.

Although it was initially all very scary, we were reassured that this was a very treatable condition and that knowing he had it was the most important thing. If we hadn't known, we could very well have let him sleep longer than he should have and the consequences could have been tragic. The most dangerous time for kids with this disorder are the first few days of life (when breastfeeding is not well established or mom's milk isn't yet in) and during times of illness (when parents waffle about whether they should seek medical attention or attempt to treat an illness at home with fluids and TLC).

In less than 24 hours, my emotions had gone from blissful love of our newborn to fear and uncertainty and panic to largely thankfulness (and more blissful love, of course). I was thankful that the lab technician who fed those little drops of dried blood through the machine spotted the abnormality late on a Friday night and called the metabolic specialist to report it. I was thankful that the metabolic clinic contacted our pediatrician with information that could save LB's life and that our pediatrician called us after hours on a Friday night to relay all this information. He told us that he had trouble locating our contact information and had to call the postpartum unit at the hospital to get our contact info off of my chart (and convince them that the situation was urgent enough that they should ignore the HIPAA laws that would ordinarily prevent them from sharing this information without a signed consent form from us -- something they could only get if they had our contact info in the first place). When he got off the phone with the hospital, he had multiple phone numbers for us and our home address and he said he was prepared to show up on our doorstep, if necesary, to check on LB's welfare that night to make sure he was ok. What a great pediatrician!

While we certainly would rather this not have happened to LB, it seems like it will be manageable and he will live a healthy, normal life. We will just need to be extra attentive to him during his first year (delaying the holy grail of parenthood -- having your kid sleep through the night -- for a little while longer) and keeping an eagle eye on him to make sure he's getting enough nutrients when he has an illness.

We want to make sure that LB remains healthy and happy and we will do everything in our power to make that possible. We also want to make sure that he lives a normal life. We don't want this diagnosis to dominate his existence. He is not a "sick" kid. He's our adorable little boy, who may very well need an extra snack now and then. That's all.