Loading summary
Transcript11 lines
- [00:00]
A
Black Friday Savings are here at the Home Depot, which means it's time to add new cordless power to your collection. Right now, when you buy a select battery kit from one of our top brands like Ryobi or Milwaukee, you'll get a select tool from that same brand for free. Click into one of our best deals of the season and stock up on tools for all your upcoming projects. Get Black Friday Savings happening now at the Home Depot. Limit one per transaction exclusion supply full eligible tool list in store and online.
- [00:43]
B
Each year I think of how to start the show to keep you here, to let you know no words can tell how swell. When I was a kid, of the big things that we would do every year is watch the Jerry Lewis Muscular Dystrophy Telethon. I mean, it was a big thing. I mean, it was like 24 hours. We'd stay up all night. Well, we tried to. And there'd be all these stars, music acts and magicians. You know, everybody that was hot at that time would come on this 24 hour live stream back then of the Jerry Lewis Telethon for muscular dystrophy. I love the way you've always stayed with me. You've laughed, you cried, and you've even prayed with me. So Jerry Lewis, one of the things that he really, really fought for was, you know, for, for research for muscular dystrophy that was just in a special thing in his heart. Because these poor boys, because boys are the ones that are primarily affected, although there can be, there can be some manifesting female carriers, which we're gonna discuss. But if you haven't put it together, we're gonna talk about muscular dystrophy. Now, as you all always know, I mean, you know what we do here, we typically take something hot in print and review it. However, yesterday when I was on call, we did a C section on a patient who is a known muscular dystrophy carrier. Okay? She's asymptomatic even though she's gone through the traditional workup, which we'll discuss, because even though she's asymptomatic, there may be some component of effect of this because of linization. Okay? So some of the good X chromosomes may be knocked out. And so what you're left with is some of the defective X chromosomes since half are inactivated per cell at random. And we're going to talk ionization as a reminder. Okay? Anyway, so she was having her repeat C section and the issue was she already had two previous children affected with Becker's muscular dystrophy and this child, who was also a male, had an amnio, and lo and behold, the dystropian gene mutation was present in this child. Again, that's three, y'.
- [03:17]
C
All.
- [03:17]
B
That. That's a. That's pretty hard to process. All right? So at her request, we also did her opportunistic salpingectomy. And so now that's done. But that's a lot to process. So I thought, you know, what we really should cover as kind of a refresher of what this is, because we learned about muscular dystrophy. And it's actually part of what we offer some patients as part of the expanded carrier screening for maternal genetic issues. And so we need to know what that is. Okay. Especially if the random chance that you find a positive muscular dystrophy carrier, you gotta know what that means. And even though she's asymptomatic, that still requires some workup in the patient because of the potential for dystropin abnormality to affect the heart because they have a higher chance of cardiomyopathy and ventricular hypertrophy. Okay, so we're going to talk about that. So even though this is an X linked disorder, so that's the first clinical pearl, as a reminder, remember that either Duchenne muscular dystrophy, a dmd, or Becker's muscular dystrophy, which are allelic. Right. They affect us. Both come from the same gene mutation, but in different parts of the gene that are affected, so that the much more severely damaged cells are. With Duchenne muscular dystrophy, those usually present much sooner, like around age 5. Whereas Becker's, which is also in the same gene, but causes some protein to be made, but just not in the normal amount. So it's much weaker form. They usually present much later on, like age 10 or. But nonetheless, they will be affected. All right, so this is a big deal because we need to remind ourselves what SMA is, spinal muscular atrophy, and what muscular dystrophy are. Because while they both present with widespread devastating muscular dysfunction, SMA, just as a point of recall, that is part of the Tier 1. That means universal maternal carrier screening test, along with cystic fibrosis and hemoglobinopathies with. Whereas muscular dystrophy goes down to tier three, means it has to be part of the expanded, which is fine, but that moves up in its importance, especially if there's a family history of muscular dystrophy, but it's not part of the routine. The core for maternal Carrier screening. Remember, according to acog, it's only three. Cystic fibrosis, SMA and hemoglobinopathies. Some throw in their fragile X, but that's really also based on family history. You gotta go down to. Then that's tier one. Tier three is the expanded. Which, of course, if you live in the world of genetics like the American College of Medical Genetics do, that's the acmg. They're like, oh, no, we should do that for everybody. And that's fine. Yes, we do find things that are important to figure out, but then also we have to deal with that. So if you find a patient who is an asymptomatic carrier who's found to have this mutation in the dystrophin gene, you can look, the good news is, hey, you're asymptomatic. Good news is, nobody in your family has this. Maybe this is brand new. The not so good news is, you could be a manifesting carrier later. So we gotta check your heart. And if the child that you're carrying is a male, then we really need to be worried about that because there's a 50% chance that that child's gonna be affected. And if it's a female, there's a 50% chance that they could be a carrier. So we're gonna talk about this because that is typical X LinkedIn transmission. So just as a brief reminder, this is like an old school, you know, genetics recap. And that's fine. We're not necessarily covering a new article. We just wanted to kind of remind ourselves that these things are out there. Okay? These things are out there. And it's not the same thing as sma. That is a motor neuron issue. And the survivor motor neuron defect that has to do with neuronal problems that therefore don't feed the muscle. So the muscle atrophies. Whereas muscular dystrophy is a problem within the skeletal muscle itself. All right? It's within the muscle defect, which is a dystrophin protein that's not made or not made. Well, because of a defect in the dystropian gene that is strictly located on the X chromosome. Now, before we get into this, I said in the beginning that we used to watch the Jerry Lewis telethon. Now, some of you. I am absolutely sure of it. And that's okay. Absolutely sure of it. You don't know who Jerry Lewis is. Shocking. And that's heartbreaking. Jerry Lewis was back in the day, before I was, before I was around. But it was Dean Martin and Jerry Lewis, they were the dynamic duo, right? That was the original little comedy act. Dean was a sophisticated gentleman, you know, the crooner. And then Jerry Lewis was kind of this, you know, a little goofy little sidekick. But Dean and Lewis, man, that was a big thing.
- [08:10]
C
Singing a song side by side we.
- [08:15]
B
Don'T know what's coming tomorrow, tomorrow and maybe it's trouble and sorrow but we'll travel the road sharing our love so Dean Martin and Jerry Lewis, I mean, many, many years of camaraderie. And then it was a horrible divide. They finally make amends until before, you know, they both died. But the legends in Hollywood and thankful for Jerry Lewis for calling attention all those years to muscular dystrophy with the Muscular Dystrophy Association. Unfortunately, there is still no cure for this, but it is part of the expanded panel, which is why it has to do with what we're talking about here in maternal health. So anyway, quick recap on muscular dystrophy. A quick genetic recap because it happened. Guys, we had a patient just yesterday, as I mentioned, with this. So anyway, I think I've set it up enough now. Let's get out of the intro and we will be right back. This is Dr. Chapa's ob gyn no spin podcast.
- [10:10]
D
Toast the holidays in a new way and raise a glass of Rumchata, a delicious creamy blend of horchata with rum. Enjoy it over ice or in your coffee. Rumchata. Your holiday cocktails just got sweeter. Tap or click the banner for more. Drink responsibly. Caribbean rum with real dairy cream. Natural and artificial flavors. Alcohol 13.75% by volume. 27.5 proof. Copyright 2025 Agave Loco Brands Pojoae, Wisconsin. All rights reserved.
- [10:39]
C
This episode is brought to you by State Farm. Listening to this podcast. Smart move. Being financially savvy. Smart move. Another smart move. Having State Farm help you create a competitive price when you choose to bundle home and auto bundling. Just another way to save with a personal price plan. Like a good neighbor, State Farm is there. Prices are based on rating plans that vary by state. Coverage options are selected by the customer. Availability, amount of discounts and savings and eligibility vary by state.
- [11:09]
B
Well, we're just about ready, Jennifer. You might be ready, Julius. But if I were you, I'd think about it. Before. Before the redo of the Nutty Professor. It was Jerry Lewis. Jerry Lewis was the original Nutty Professor. I wasn't around. This was before my time. But you know, Eddie Murphy was not the original Nutty Professor. It was Jerry Lewis urges you to see this picture from the beginning on penalty of losing your popcorn privileges. One thing we will tell you is that Jerry plays the part of an eccentric chemistry professor. Yeah, those were when movies were just made differently. So anyway, yes, Jerry Lewis been around a long time. God bless Jerry Lewis's memory. All right, so on to say, he did a lot for mda. And I really felt for this patient that we had yesterday. I mean, previously affected children. She's a carrier. She's already gone through her cardiac eval. My goodness. And this child that we just delivered yesterday has the mutation. Okay, now we know that because we know that she's a carrier. We had amniocentesis because we knew that this child was a male. And lo and behold, amniocentesis said, yes, this child has the same mutation, which in this case is going to be very similar to the others, which is Becker's muscular dystrophy. Same part of the X chromosome affected, but that dystrophin gene is so friggin big that you can get different allelic presentations. Right? So if you wipe out the protein completely and the protein which makes the muscle function correctly stabilizes the muscle wall called the sarcolema. Ooh, remember that? The sarcolemma, the membrane of the muscle. If you get the defect that doesn't make any of that stabilizing protein, then you get Duchenne muscular dystrophy, much more severe with muscle weakness and wasting where the muscles basically atrophy. They become dystropic and they get replaced by scar tissue and fat. Okay? Devastating. These end up having cardiac issues, respiratory issues, and still no cure. It's devastating. Okay? But if you have the allelic mutation on the X chromosome that does make some protein, it just doesn't make a lot of it. You get the milder form called Becker's muscular disk, represents a little bit later, but still universally going to be kind of wheelchair bound. Muscular contractions at some point and difficulty with breathing and orocardiomyopathy leads to a shortened lifespan in these conditions. It's devastating. Okay, So I really felt for her because, man, look, we should feel for all of our patients. That's called empathy and compassion, you know, for anything. But when it's specifically when it's a genetic issue, when you're born with a card that you have to play, I mean, you can't exchange it right now. I mean, there's no gene therapy for that. Although I'm sure in the future that's been talked about as a way to kind of replace, replace that protein that's missing for muscular dystrophy. But we're not there yet. So, anyway, good reminder, a good refresher that these things are out there. This is part of the expanded panel which we talked about earlier from the American College of Medical Genetics, acmg. That's called their tier three. And remember that this is X linked. Now, most carrier screenings are looking for things that are autosomal recessive, but this is not one of this. This is X linked. That's why it's tier 3. Meaning if the patient has it, typically she's not gonna be symptomatic because she has another good X chromosome. Because women have two X chromosomes and so they're not typically affected, although some can have some muscle cramps, muscle weakness. And all carriers, all female carriers of this need a cardiac eval, and they need an echo and or cardiac mri. They can get a screening of their serum creatinine kinase levels to track that, because CK levels will rise as the muscle becomes damaged. CK will leak into the bloodstream, they get elevation in ck, and so even though they're asymptomatic because they have a healthy X chromosome, they still are at risk for cardiac manifestations, either left ventricular hypertrophy or cardiomyopathy. And so they still need an eval, which our patient had. Okay, now remember, this is X linked. So even though a patient, a woman, has two X chromosomes in the cells, only one X chromosome works at a time. Y' all, remember, this is old school. Old school refresher of genetics, because we all learned this a long time ago, but I get it. We forget, but we knew this, that only one X chromosome in a female is working at a time because one of them is knocked out. That's called lionization, or X chromosome inactivation. So only one does the job. So because if a woman has two X chromosomes, some cells will knock out the good X, leaving the bad one, and some cells will knock out the bad one, leaving the good one. That's why they're. In general, they're asymptomatic, although it depends on what degree the good chromosome X is taken out. And if you have more of the dysfunctional X chromosome that's active in the cells, then that's where you get some form of manifestation manifesting symptoms like the muscle cramps, spasms, and, or the cardiac issues, which is why all carriers. So that's another clinical pearl. All carriers of muscular dystrophy need cardiac evaluation. Okay, now, even though we're talking about The X linked variety. And the two most common are muscular dystrophy or Duchenne muscular dystrophy or Becker's. There's actually other muscular dystrophies out there, but they work by different mechanisms. Okay? This X linked condition affects what we've already talked about. This protein quantity called dystropin, that helps stabilize the skeletal muscle surface, okay, the skeletal muscle membrane. So very quickly, if you can think about it, dystropin is kind of like a scaffold, kind of like a wooden beam holding up the ceiling that's connecting actin and the other protein structures to the muscle membrane, which is the roof. If that supporting beam is gone, which is the dystrophin protein, then the roof, called the sarcolema, the membrane is gonna fall. And when it falls down and crashes down, then the muscle becomes affected, it gets scarred, and you get replacement of healthy skeletal muscle with muscle with fat and with scar tissue. Okay? That's the dystropic condition. Even though initially for males who are the ones who are affected because they only have one X chromosome, then they initially have a period of skeletal muscle hypertrophy. Remember, if you think of the old textbook USMLE genetics, picture of a little boy walking with kind of a waddling gait but very big calf muscles, you go, that kid needs a muscle biopsy for muscular dystrophy. Because as the muscles try to compensate for their decaying structure, they actually get hypertrophied. But obviously that's only works for a certain amount of time and then they start to atrophy. But typically is a child around the age of five who's waddling around with very big calves. Oh, look at. Look how jacked up that little boy is. He's got. Look at those calves. Yeah, that's probably a bad thing. And so they need a muscle biopsy.
- [18:35]
D
Every holiday shopper's got a list.
- [18:37]
B
But Ross shoppers, you've got a mission like a gift run that turns into a disco snow globe, throw pillows and PJs for the whole family, dog included. At Ross, holiday magic isn't about spending more. It's about giving more for less. Ross, work your magic. Now, that's old school. And now we can find this before they're born. Of course, with maternal carrier screening. And if the mom is found to be a carrier and the child that she is carrying is found to be a male, meaning their xy, then that child, that pregnancy should be offered amniocentesis to see if that X, which is part of the XYZ has the mutation, in which case it will always be symptomatic. Or if it is not, the messed up X chromosome, but it's a good one, which means they dodged a bullet. Okay, so remember, the 50% of male offspring for a carrier of muscular dystrophy will be affected. And for female offspring, for daughters of a carrier, 50% can be a carrier of the mutation. All right, so once again, these are big issues that we learned this in genetics, in medical school. You should have learned it in nursing school, I hope. I don't really know what the nursing school curriculum is, but this is why we're doing this, because they're out there and it's a good refresher. Okay. Actually, I asked one of our residents. I'm like, hey, tell me about muscular dystrophy. Like, oh, we screen for that in all pregnancies. Do we? Well, isn't that what we screen for? Isn't that part of the recommendation of the core? No, because they confuse that with spinal muscular atrophy. Okay, so spinal muscular atrophy is neuronal condition. This muscular dystrophy, either Duchenne or Becker's, is a muscular issue, and it is not tier one. It is tier three. Okay. Thankfully, it's not all that common. In terms of live born male births, it's about 1 in 3,000, some say 1 in 3,500. So not very common. But it is out there. And if a patient is either a familial carrier, meaning it's passed down by family history, or it could be a de nouveau mutation, like, nobody in the family has it. Boom. Now this woman, her X chromosome during meiosis, as she was forming, just there was a point mutation or a miss shift or some nonsense mutation that messed up that part of the X chromone responsible for dystrophin protein. And now she has it. So while most of these are family history based, this can occur de Nouvo without a family history. Okay, so if you do an expanded panel, you're like, oh, my goodness, you've got muscular dystrophy carrier, which means now you're committed to a cardiac workup. But I thought you told me you didn't have anybody in your family with any kind of issues. Because I don't. Well, then that means that this is denuvo. Or it's been there all along. It's just it hasn't manifested. Or the males in the family line have by chance gotten the good X chromosome as part of their genetic makeup of xyz. Okay, Is that wild or what? I think this is fascinating, and it's also devastating at the same time. I don't want to belittle this. This is a devastating and a very sad condition. So symptoms, of course, for Duchenne, muscular dystrophy includes muscular weakness. They all get this. Muscle cramps, myalgias, muscle fatigue, and eventually skeletal muscle atrophy and then replacement by scar tissue and contraction. Devastating. Devastating. So the good news is, is that once again, it's identifiable. The horrible news is, well, there's really no good treatment for this. It's all supportive care, but awareness is a big deal. The other sign, if the mother didn't have expanded panel and there's no family history, if that kid starts to ambulate and getting up from the floor around the age of five or so, if he has to get up and hold his legs in position with his arms, kind of like has to brace himself and push himself up, then that's a sign of muscular dystrophy as well. And that's called Gower sign. So these are all things that we have to be aware of. That's why it's important to keep those pediatric appointments. But even us in women's healthcare, we need to be aware of this, because these are things that we need to take a look at when she comes in with her child. Like, that kid has pretty big calves, and I see it's a male. If you didn't have carrier testing, maybe we need to do a biopsy on that and see how that child has his gait and how he's getting up from the floor. Those are all first signs of developing muscle weakness because it affects those muscles in the legs. Okay. All right, so very quickly, we talked about the symptom, symptomatology from a carrier standpoint. And again, it's gonna be very quickly, very quick. Guys, I just want to give you the quick highlights here, because this is what our patient had. Per protocol, if you find a patient who is a carrier, as we did in this case with her, ask her if she would complete a cardiac evaluation. And she did. We needed to do this. You can either do a cardiac mri, you can do an echo, but these are patients who are at risk of having dilated cardiomyopathy and potentially heart failure, especially as the years pass down the line. Carriers, female carriers, can have left ventricular dilation up to about 15 to 20% of the time. Thankfully, dilated cardiomyopathy is much less. Happens about 8 to 10%. But one of the ways that you can track that, of course. And how they're doing is by checking their serum creatinine kinase, their CK levels, because those will start to rise in about 30 to 50% of the cases. Okay, so this is very quick. Again, it's not doing a quick article recap or a summary. I just wanted this to be a very quick summary and a refresher of medical genetics for muscular dystrophy, since we just had a patient yesterday. And that's all just a quick reminder that these are things that are out there and that we should really be thankful when we have healthy children, when we ourselves are healthy. Man, it's amazing how many things can go weird just in biology, guys. It's odd. And the reason that this specific gene, this dystrophin gene, is so at risk is because it's very large. The bigger a gene is, guys, on the X chromosome or on any chromosome, the more room for error during meiosis. And that's the issue here, is that this thing is a big chunk of the X chromosome and is prone to denuval mutation. Anyway, we've covered Duchenne muscular dystrophy and Becker muscular dystrophy as it relates to carrier testing. Just a quick recap. I don't want to belabor this. I think we're done. And I think next time we'll get back to a regular summary, as we always do. Podcast family, we're thankful for you. We're glad you're part of our podcast community. I am post, call, and beat, so I'm going to bed. As always, we'll see you on the next episode of the no Spin podcast. And now that we've done all that, Michael, let's take it home. This has been Dr. Chapa Zobi Gyn no Spin podcast podcast family. Thank you for your support. Thank you for listening. And as always, we'll see you on another episode of the no Spin Podcast. Sam.