imprinting is a really really high-yield topic it shows up out of the epigenetic section of first-aid and all the other resources and it's actually a really simple topic if you take a few minutes and you get this down you're basically giving yourself free points on test day so we decided to make a video highlighting the importance of these topics so what is imprinting first we're just going to start with a really basic overview imprinting is basically when genes get turned off so if you recall from genetics and biochemistry that when a gene is methylated it is basically silenced right it's turned off and this imprinting depends on maternal versus paternal inheritance of that gene so depending on where you get the gene from you know mom or dad it determines the phenotype that's expressed when one of the genes is methylated ie turned off so that brings us to two high-yield diseases that show up on USMLE and comlex all the time prader-willi syndrome and Angelman syndrome i'm not sure if it's angleman syndrome or Angelman syndrome but we're gonna call it Angelman syndrome so prader-willi syndrome and Angelman syndrome are two diseases that show up when one of the genes on chromosome 15 gets deleted or methylated or turned off so we're gonna go through how you're gonna remember this we're gonna show you an advanced organizer kind of in the realm of sketchy slash pic monic where there's gonna be a picture and you're gonna remember it based on the picture it's super simple and it's free points so let's get started so the first thing you need to do is ask yourself is the chromosomal deletion from paternal inheritance or maternal inheritance so that that's our first question here now let's say we want to remember which one is the paternal deletion so the paternal deletion is prader-willi syndrome so the peas give it away paternal prader-willi between the words paternal and maternal there's only one p so it's got to be prader-willi syndrome now consequently if we're gonna figure out what is the maternal deletion well that's gonna be Angelman syndrome there's only an M in Angelman there is no M in prader-willi therefore the M and lines up with the M in maternal so the first high-yield fact is already covered a lot of the times are going to describe a patient to you that has one of these two diseases and ask you is this paternal or is this maternal and the easy way to remember it is paternal prader-willi maternal Angelman so just line those letters right up so now you need to know the symptoms of each of these two diseases and there are there's one huge huge huge symptom of each that gives it away but just in case you have trouble remembering it here's our advanced organizers so for prader-willi syndrome Prater rhymes with Vader so we're gonna think about Darth Vader and here is our little Darth Vader now what do you notice about little Darth Vader Willy here well Vader Willy is really fat and really short and that is the highest yield piece of information about prader-willi syndrome these patients get hyperphagia right they eat and they won't stop eating and this leads to obesity by nature these patients are just short statured in additional if you want to go the next layer deep type of thing an additional symptom is that they have hypogonadism so in this picture if you look at our little Darth Vader Willy you can't see any testicles so it's hypogonadism but the biggest thing to take away from this is paternal prader-willi remember Vader Willy here who is short and fat so hyperphagia and obesity and short stature those are the two big giveaway symptoms that hyperphagia is really gonna lean you in the direction of prader-willi so don't forget Darth Vader Willy the paternal deletion for genetic imprinting now let's switch gears and talk about Angelman syndrome so if you couldn't already guess we're gonna go with the angel for Angelman syndrome the biggest piece of information the most high-yield symptom that you absolutely cannot forget is that an angel man syndrome there's inappropriate laughter so in this picture you see that the angel is laughing inappropriately so so these patients you know they're gonna describe to you a very young patient who's just laughing inappropriately non-stop uncontrollable laughter so remember our angel here who's additionally secondary symptoms that could lead you in this direction are seizures and speech delay so if you look in this picture for seizures there's the crown above the angel so remember that that crown on the head of the angel represents seizing in a central nervous system and as far as speech delay goes notice that her hands are in front of her mouth as if to say that she cannot speak or she's delayed in speech so while there's inappropriate laughter there is a speech delay if you see the buzzword happy puppet its Angelman 100% because these patients laugh so inappropriately and they're always in perceivably in such a good mood they are referred to as the quote happy puppet children so anything with laughing or happy puppet is gonna be Angelman syndrome so now let's summarize really quickly there's a deletion on chromosome 15 you need to remember chromosome 15 just committed to memory and the deletion can either be paternal or maternal paternal is prader-willi and maternal is Angelman so the m's and the peas prader-willi we think darth vader willie we think of our little short fat Darth Vader remembering that hyperphagia and obesity is the key hallmark high-yield symptom of prader-willi syndrome for Angelman we remember our inappropriately laughing little angel inappropriate laughter also with some seizure and speech delay but the big one is the inappropriate laughter that is your quick high-yield review of prader-willi syndrome and Angelman syndrome remember imprinting is a very high yield topic but if you take some time and get it down in this video you will be giving yourself three points on test day