DIP Episode 424 - HY Rules For Remembering Modes of Inheritance

Okay, welcome. My name is Devine. This is episode 424 of the Divine Intervention Podcast. And in today's podcast, I'm going to be, is actually going to be a pretty short podcast. Into these podcasts, I'm just really going to be discussing how to remember the modes of inheritance of genetic diseases. I will very likely in the future have podcasts on autosomal recessive, ex-linked recessive. I'll have like specific 10 of podcasts for those. But I just figured I'll make a short podcast that can just really help people remember the modes of inheritance. Now, this podcast, the goal is to focus on rules. Specific disorders can be discussed in future podcasts and also have podcasts as well that address some of these genetic diseases already. So let's talk about some rules that can really, really help you with these problems. Now, let's start off with autosomal dominant disorders. So the thing with autosomal dominant disorders is sometimes again, it's hard to remember which is which like man, this disease is here, this disease is here, that disease is there. But again, when you can group things or categorize things, it makes them a lot easier. So what are the classic problems that I'm hearing here in an autosomal dominant fashion? The first thing I would say you want to know are structural proteins. When something is a structural protein and you have a deficiency or a defect, it's usually an autosomal dominant fashion.

So like for example, if you have like defects in like collagen or defects in febrieling, right? That's like in Marfans, right? Or you have problems with like the structural proteins of your red blood cells. So like tick for example, hair districts are like toses with those spectrum and anchoring problems. Those are all autosomal dominant problems. Or let's say you have problems with like a receptor of a membrane. Again, those are usually structural problems. Those things will usually be inherited in an autosomal dominant fashion. And also, many of the cancer syndrome, many of the hair-editary cancer syndrome, most of them have autosomal dominant inheritance. Again, if you also see gain-of-function problems, whenever you see problems with like gain-of-function mutations. So for example, you see like e-contropleasure for example where you have like a gain-of-function mutation in FGFR3. Most of those things end up being inherited in an autosomal dominant fashion. So I'll say those are classic things to keep in mind with autosomal dominant diseases. So again, to summarize, when you see problems with structural proteins, things that have to do with structure, right? Like the cytoskeletal proteins of your red blood cell, like spectra and anchoring, band proteins, things involving collagen, fibrillin, even like membrane receptors, like the LDL receptor, that's almost always going to be inherited in an autosomal dominant fashion.

And again, whenever you have like a hereditary cancer syndrome, most of the time not always, again, notice these rules are generalizations, they don't always hold, but they are very good guestimits on exams. When you see a hereditary cancer syndrome, many times autosomal dominant inheritance, when you see a gain-of-function mutation, right? Like e-contropleasure, hunting disease, believe it or not, is a gain-of-function mutation, right? Most of those things end up inherited in an autosomal dominant fashion. Now, another classic pattern of inheritance is X-linked dominant. So the thing about X-linked dominant is, honestly, you just need to commit them to memory, because there is so few of them, it's almost incredible loss that you choose to not memorize them. And X-linked dominant disorder, the key critical ones to know, fragile X syndrome and out-port syndrome. Those are the two big ones, fragile X syndrome and out-port syndrome. If you want to throw in another one, you can throw in hypophosphatemic rickets. That's basically a person that has rickets that is resistance to vitamin D, hypophosphatemic rickets. That one also has X-linked dominant inheritance. And then red syndrome. Red syndrome also has X-linked dominant inheritance. Red syndrome, many times is tested on psychiatric shelves and also on USML exams, where you have that MECP2, that MECP2 gene mutation. That's also X-linked dominant.

For the two ones, I will say that, oh, if you're like, divine, you've given me four things. I got to memorize only two. The two you definitely want to memorize are fragile X syndrome and out-port syndrome. The X-linked dominant disorder is instead of memorizing a categorization, memorize them because there is so few of them. Another one too that's also very helpful to just say, you know what, I'm going to memorize these things because there's so few of them at those mitochondrial inheritance disorders. There's no great categorization with them. So you just got to commit them to memory, right? And many times the critical thing you're looking for, even if you cannot memorize the disorder names, the critical thing you're looking for in exams are the present of ragged red fibers. Ragged red fibers. When you see ragged red fibers, I'm telling you this, you really want to think about mitochondrial problems. And you'll notice that, wow, the mom has a problem and all the kids get it. That's going to be a mitochondrial problem. Just remember the ragged red fibers. Now, what are some of the classic things you need to memorize here? I'll see there are three of them that classically show up on exams. One is Milos, right? Where you have mitochondrial inheritance, a phyllapathy, lactic acidosis and stroke-like episodes. So you see a child, they have all these stroke-like problems, right? They have these neurodefesis that come and go.

They have like profound lactic acidosis, think of Milos. Another mitochondrial disease to memorize is called L-H-O-N, labors, hereditary optic neuropathy. Again, they're going to mention something about ragged red fibers. What it may give you is an image of ragged red fibers. You should be able to identify ragged red fibers on M-B-M exams. And then I know when you miss your exams is M-E-W-R-F, right? Myoclonic epilepsy with ragged red fibers. Literally, ragged red fibers is in the name. So if you want to remember a key headline for mitochondrial inheritance, and again, I'll probably have a specific podcast on this stuff. Just think of ragged red fibers, okay? Think of ragged red fibers. Think of ragged red fibers, right? So again, just to summarize where we are now. So we've talked about some rules for identifying the Zomodominant Diseases. And then we've said that you know what, for excellent dominant diseases, it's just easier to memorize them. We said that for mitochondrial diseases, also just useful to just go ahead and commit them to memory. So now, let's go ahead and go to autosomorecessive diseases. I guess we've talked about autosomore dominant. Just talk about autosomore recessive. Now, the good thing about autosomore recessive diseases think of enzyme problems. Again, it doesn't always hold, but it's a very useful rule of thumb. When you see enzyme problems, think of autosomorecessive inheritance. You see enzyme problems, think autosomorecessive inheritance.

And also, if you have a mutation in like a DNA repair gene, most of those things also have autosomorecessive inheritance. So just look at most of the enzyme defects you know, like, ooh, when a person has the deficiency of adenosine diaminase, right? In skin, that's a classic autosomorecessive disease, right? So when you see enzyme problems, think autosomorecessive diseases. When you see DNA repair gene problems, like etaxia, telangetasia, bloomsendrom, xeriderma pigmentosum, phankony syndrome, these things are usually inherited in an autosomorecessive fashion, okay? So DNA repair gene problems think of autosomorecessive disease. Now, the next pattern I'm going to go to are x-linked recessive diseases. x-linked recessive diseases. So here's the thing. x-linked recessive diseases, they kind of share some properties with autosomorecessive diseases. But because the thing is quite a number of enzyme defects, I inherited in an x-linked recessive fashion as well. So that enzyme rule, I would say the thing you should think about with a lot of enzyme defects, think autosomorecessive, but a decent number of enzyme defects, I also inherited an x-linked recessive fashion. So that's just something you kind of want to keep at the back of your mind on exams. But I'll say most enzyme defects, you'll see on them being exams, they're going to be autosomorecessive, but some of them are x-linked recessive. Some of them are x-linked recessive.

And I'll say in general, those ones that are x-linked recessive, they're kind of high you to commit to memory, right? So things like hunters, disease, g6pd deficiency, right? That's x-linked recessive, lesh-my-hand syndrome, where you have a deficiency of HGPRT, hypoxanthin, guanin-inforced, where I both sell transverse, that's also x-linked recessive, right? Or if you have like an only thing trans-cabamolese deficiency, right? That also has x-linked recessive inheritance. But in general, most enzyme defects, I inherited an autosomorecessive fashion, but a few select enzyme defects, I'll say probably the most important one, that your classical exam exams are lesh-my-hand and g6pd deficiency. Those are two like very high-yield exceptions to that, the enzyme defects that are inherited in an x-linked recessive fashion. Now, one that, one rule that is profoundly helpful with x-linked recessive diseases, are your immunodeficiency diseases. I'm telling you, immunodeficiency diseases, most of the ones you will see on exams, have x-linked recessive inheritance. Why is that? The thing is, many of the genes in your immune system are actually on the excromusone, believe it or not, right? So like many of those things, like for example, if you see like Bertonsi Gamma-Globo-Linemia, boom, x-linked recessive inheritance, we've got all drugs, boom, x-linked recessive inheritance, CGD, boom, x-linked recessive inheritance, right?

So that's just a really helpful thing to keep in mind on exams. Another thing that also falls in this x-linked recessive inheritance pile are the hemophiliaes, hemophilia A and D, right? The examples of x-linked recessive disorders. So these things should only show up in boys on exams. And other ones you may also see in terms of x-linked recessive disorders are the muscular discharfies. Like the common ones you see on exams like beckers and douchins, those have x-linked recessive inheritance, okay? Those in general have x-linked recessive inheritance. So again, these are rules. They don't always obtain, but they are very good decent rules to know. So just to summarize, because I feel like just this repetition will help some people remember this well. We've talked about how to like generalize for autosomal dominant disorders, for autosomal recessive disorders, for x-linked recessive disorders. And we also said that it's helpful to remember to memorize the mitochondrial disorders. And we also say that it's very helpful to memorize the x-linked dominant disorders, because those are a very limited repertoire. So for the most parts, they are just pretty useful to memorize. So again, I'm going to stop here, but again, I just want to do one last summary of the key points that I said just to really get these points into your head. Again, the x-linked dominant disorders, you need to commit them to memory, because they are very few.

The classic ones on exams are outport syndrome and fragile ex-sendrum. If you want a bonus, two extra. Think about typophosphatemic reggae and think of red syndrome, R-E-W-T syndrome. And then I said that mitochondrial disorders, you need to commit them to memory as well. They are almost always associated with ragged red fibers. And they include Milos, they include Merf, and they include L-H-U-N, labors, hereditary, optic, neuropathy. And then I said for autosomal dominant disorders, always think about structural proteins. Any protein that involves structure, usually is in herithid, in an autosomal dominant fashion. Or something involves like a membrane receptor, right? Like when you have some of these familial hypercholesterolemium, so you have like an LDR receptor problem. Many of those things have autosomal dominant inheritance. And also if you have a hereditary cancer syndrome, that's usually autosomal dominant. When you have a gain of function mutation, that's usually autosomal dominant. And then we said for autosomal recessive, the big, big, big two categories. You want to keep in mind our enzyme defects and DNA repair defects. Those things are usually in herithid, in an autosomal recessive fashion. And then exling recessive, I said that there are certain select enzymes, enzyme defects that are in herithid and in an exling recessive fashion. I said that those are high auto-memorize, especially G6 PD deficiency, and Lisch-Meijan syndrome with HGPRT deficiency.

Those are the big, big, big, big ones to keep in mind. And then I said for exling recessive as well, think of the muscular dystrophies, the classic ones on exams, and also think of the immunodeficiency diseases. Most of them with very few exceptions, I inherited in an exling recessive fashion. So again, I really hope you found this podcast to be helpful. I will in the future, God willing, have specific podcasts that address each of these different modes of inheritance and the classic representative diseases and a few things relating to like, oh, how you miss spot them on a pedigree and things like that. And I do offer one or one tutoring for many exams, step one to step three, complex one to three, preclinical, medical exams, third issue of exams. I have review courses taking place in the month of November. If you want information on those, shoot me an email. I have a testing course taking place this month. I have a biostatistics bootcamp taking place this month and a 20-hour review course also team, please this month. And then I also help with mock interviews and errors apps. If you need help shoot me an email through your website. I'll give you more information. I have these podcasts on the major podcast apps Apple podcast Google podcast Spotify. And I also have a You Tube channel divine intervention, USM, any podcasts and videos where I post the videos that I make. And then I also have a new website called divineinterventionlifelessons.com.

Divineinterventionlifelessons.com. It's a Bible Bees website that has you know puts out two podcasts a week that address a common problem faced by humanity from a biblical perspective. It's actually an Apple podcast associated with that. It's called the divine intervention life lessons podcast. So if you're interested, just feel free to check that out. And then a quick life lesson I just want to give today is I just want to speak to the importance of thinking and not just accepting thinking and not just accepting. The thing is there are many people that fall into this problem in life where because some authority figure says X they then believe that X is true. No, you need to learn to think for yourself. Even if that thing now 30 figure may be seen is true. It may not be true for your specific situation. So many people are particularly prone to oh, when some authority figure says something, wow, I need to take it as hook line and sinker. Yes, many times authority figures, especially if it's the air of expertise. They usually know what they're talking about. But again, it's just always helpful to be a person that verifies things. Be a person that verifies things. Like for example, in this podcast, I'm teaching you all this stuff. Well, like consider myself to be at least have some degree of expertise with the USMLE exams, right? But even after I've thought you something, you should still go back and verify. Right?

The fact that oh, wow, the vine has made 400 plus podcasts relating to the USML Es. It doesn't really mean anything in the grand scheme of things. Okay, maybe you should trust me more than some regular person you meet on the street. But again, it's just always helpful to be able to think for yourself. Right? Think for yourself. There are certain things that are commonly accepted out there that are not particularly, especially like I've seen this as a person that has tutor that has taught the USML Es for years. There are certain things that are commonly accepted out there that work for many people, but you don't work for certain people. There are some people where reading like doing a particular Q bank may not be what will help them. They may be some people where like having a somewhat different focus with their studies may help. So I'm just encouraging you just be the kind of person that goes back, right? Goes back. After you've heard from this authority figure, just go back and cross check and see, okay, does this thing really make sense? And just ask yourself, this thing that this person said does he make sense for my particular situation? Because that authority figure may be absolutely right. But for your particular situation, it may be absolutely wrong. Like for example, in Stony first step one, you know, the classic things that many people do, I did not necessarily do because for me, I'm like, hmm, these things will probably not work for me.

I did think that are very different for what many people did, but they ended up working out well for me in the end, right? So I'm not saying that you should, every authority figure should trash. No, the authority figures for a reason, right? But again, after you've heard something, take that information and think. Many people don't like doing data analysis in this world we're living today. Take data from someone or think through that data. And as you do so, I really hope that you're successful. So thank you for listening to me. I'll see you next time. Have a wonderful rest of your day. God bless you. Bye for now. Thank you.

Defects in proteins involved in structure, such as collagen, fibrillin, cytoskeletal components (e.g., spectrin), and membrane receptors.

Look for "ragged red fibers" (RR Fs) on muscle biopsy; this suggests a primary defect in oxidative phosphorylation/mitochondrial function.

Fragile X syndrome and Optic Atrophy Syndrome.

Enzyme defects (e.g., ADA deficiency) and DNA repair gene problems (e.g., Bloom syndrome).

Immunodeficiency diseases (because many immune genes are located on the X chromosome), hemophilia, or certain select enzyme defects like G6 PD deficiency.

Mitochondrial disorder; suggests a defect in oxidative phosphorylation/mitochondrial function (maternal inheritance).

Autosomal dominant.

G6 PD deficiency and Lysosomal storage defects involving HGPRT (Lesch-Nyhan syndrome).

Gain-of-function mutations (e.g., FGFR3 in achondroplasis).

Enzyme defects and DNA repair gene problems.

Immunodeficiency diseases (e.g., CGD, Barton's).

Mitochondrial disorder; suggests a defect in oxidative phosphorylation/mitochondrial function (maternal inheritance).

Autosomal dominant.

G6 PD deficiency and Lysosomal storage defects involving HGPRT (Lesch-Nyhan syndrome).

Gain-of-function mutations (e.g., FGFR3 in achondroplasis).

Enzyme defects and DNA repair gene problems.

Immunodeficiency diseases (e.g., CGD, Barton's).