PKU, Phenylketonuria, Galactosemia, Hereditary Fructose Intolerance & Sorbitol Diabetic Cataracts

www.stomponstep1.com/pku-pheny...
Phenylketonuria (PKU) is a genetic deficiency of either Phenylalanine Hydroxylase or its cofactor, Tetrahydrobiopterin (THB). This inhibits the conversion of Phenylalanine to Tyrosine. The lack of Tyrosine causes multiple health outcomes and the excess Phenylalanine is excreted in the urine as it builds up in the body. Untreated PKU is characterized by Mental Retardation and Seizures. A mild form of Albinism results from less tyrosine being available for melanin synthesis. The build-up of metabolites with aromatic properties leads to a Musty/Mousy Body Odor.
Tyrosine is a non-essential amino acid as most people can create tyrosine by breaking down phenyalanine. However, tyrosine becomes essential in PKU. PKU is treated by supplementing tyrosine and restricting phenyalanine intake in the diet. Items that contain Aspartame (like diet soda) need to be avoided as well as aspartame is broken down into phenylalanine.
In tissues, some glucose is converted to an alcohol called Sorbitol. Small amounts of sorbitol allow glucose to be sequestered in the tissue and do not cause a problem. Sorbitol Dehydrogenase converts sorbitol to harmless fructose to prevent sorbitol build up. However, some tissues (primarily in the eye) do not have enough Sorbitol Dehydrogenase to handle excessive amounts of sorbitol. Therefore, patients with chronic hyperglycemia (Diabetic Patients) have a buildup of sorbitol which can cause Cataracts and other damage to the visual pathway.
Essential Fructosuria is an asymptomatic deficiency of Fructokinase. Hereditary Fructose Intolerance is a deficiency of Aldolase B that causes hypoglycemia, hepatomegaly, jaundice & vomiting. These patients should avoid fructose & sucrose (which contains fructose)
Galactokinase Deficiency causes cataracts. Galactosemia is a deficiency of Galacto-1-P Uridyl Transferase that leads to cataracts, hepatomegaly, jaundice & retardation. Patients with both disorders should avoid lactose as it contains galactose.
All four disorders above are Autosomal Recessive inheritance. Whichever sugar builds up, either the sugar by itself or the phosphorylated sugar, can be detected in excess in the urine and blood. Galactose disorders are more serious than fructose disorders because excess fructose is just excreted in urine while excess Galactose can be converted to Galactitol (alcohol) which can accumulate in tissues. Fructose disorders don't appear until the baby stops breastfeeding and is exposed to formula or other dietary sources with fructose. Lactose is a disaccharide of 1 Glucose and 1 Galactose. Therefore must be avoided in Galactose Disorders. Sucrose is a disaccharide of 1 Glucose and 1 Fructose. Therefore, Sucrose (table sugar) must be avoided in Fructose Intolerance.
Now that you have finished this video you should check out the next video in the Biochemistry sections which covers Alcohol Metabolism, Alcoholism & Methanol Poisoning (www.stomponstep1.com/alcohol-m...)
Pictures Used (in order of appearance):
This work is a derivative of "Food Cartoon Coke Can Beverage Soda Cola" available at pixabay.com/en/food-cartoon-co... Creative Commons 1.0 Public Domain Dedication
"Simple Cartoon Mouse" available at openclipart.org/detail/17558/s... Creative Commons 1.0 Public Domain Dedication
This Work is a derivative of "Cataracts in Ghana" by Mate 1st Class (AW) Shane M Available at ttp://sn.wikipedia.org/wiki/File:Cataracts_in_Ghana.jpg under Public Domain

[@DilashaNeupane]

Can't believe I hadn't come across your page yet. Thank you for the great videos!

[@stomponstep1989]

If you liked this video and want me to make more please let me know by commenting, liking this video or by subscribing to my KZbin channel. If you have a question, please don’t hesitate to ask and I’ll try to answer it ASAP.

[@richard-df6pr]

for each video in the name can you put in the average hy score e.g this vid on pku the title could be {PKU, Phenylketonuria, Galactosemia, Hereditary Fructose Intolerance & Sorbitol Diabetic Cataracts. HYscore2)

[@stomponstep1989]

richard mohammed That is a really good idea I haven't thought of. The only downside is I lose some characters in the title and the title is important for where my videos rank for different search terms. KZbin only recognizes the first 50 or so characters of a title for search purposes so using a few for the HYR could mean I can fit 1 less keyword in each title and maybe slightly less people find me via search. But I'll think about it and maybe try it out soon to see if it changes the number of views I get. I'm also considering another idea where I make 1 video per chapter that gives the high yields for the whole chapter. No actual content just a list of concepts with their high yield rating listed in descending order. Then there would be links to the actual content. Do you think that would be useful?

[@richard-df6pr]

i think there is room for both of these ideas , just make sure to make a playlist. aslo i regularly search for medical videos but it was relatively difficult to find your site. i suggest posting on reddit r/medicalschool , sdn and other blogs if you havent already done so. anyway i watched a few of your videos and like the succinctness please do make more videos , especially for step 2 because right now there is only one good step 2 free resource meded onlne resource (onlinemeded.org/ )

[@stomponstep1989]

richard mohammed thanks for the feedback! The channel/website is in it's infancy. That is hopefully the reason why you had trouble finding it. I have only been releasing videos for a couple months now. Advertising with social media, forums etc. are all things I plan to do in the future, but given the limited amount of time I have (I'm a current MS3) I figured it makes sense to focus first on building up the amount of content I have and then shift to advertising more

[@stomponstep1989]

richard mohammed Oh and "Stomp On Step 2" is definitely something I want to do in the future, but I haven't take the test myself yet so it will be sometime before I start working on that. Thanks for the comments and the support!

[@juanpena5418]

MAN GREAT JOB THIS IS AWESOME,,, CONGRATS IM JUST TAKING MY STEP 1 IN THREE WEEKS AND RIGHT NOW IM JUST REVIEWING MY DISCIPLINES,,, THIS IS GREAT,, I WAS WONDERING IF YOU HAVE ANY VIDEOS INCLUDING ANY PEDIGREES ? OR MAYBE ANY VIDEO WITH ANATOMY CHALLENGE QUESTIONS :(, BTW SORRY FOR THE CAPS

[@stomponstep1989]

+Juan Pena Thanks for commenting. I don't have any anatomy questions but there is a video with pedigrees. You can find it here www.stomponstep1.com/pedigrees-patterns-of-genetic-inheritance/

[@jeffr3773]

Thanks.

[@didowu1]

Great Thank you!

[@stomponstep1989]

+Damilola Idowu thanks and happy holidays!

[@The1RobynHode]

I think it's a generalization to say we pee out the excess fructose 'cause this process of fructose metabolism happens in the liver. I've read previous studies that have shown in many people that have already acquired diabetes or are generally overweight/obese convert more blood glucose to fructose in the liver (upwards of 30%+) vs. 3% or less from food sources. Fatty liver disease is looking more and more to be the cause of too much fructose volume. This is why Type II diabetes looks to be more of a liver-issue than Type I that is directly pancreatic malfunction.

[@stomponstep1989]

The1RobynHode Thanks for the comment. Rather than trying to cover topics comprehensively, my videos try to cover the most important information for the USMLE Step 1 medical board exam as efficiently as possible (AKA in as little time as possible). So in effect I'm intentionally trying to generalize to a certain extent. This exam presents diseases with their "classic" presentation and some of the questions were written before I was born. Therefore info based on recent studies and/or rare presentations are very low yield for the exam. However, looking into the studies you mentioned could be very high yield for somebody studying for another class or test so I appreciate you posting it

[@The1RobynHode]

Stomp On Step 1 Ah! Makes perfect sense from that approach. Thanks for sharing the information too, it was very beneficial!

[@thelifeyoulive410]

video start at 1:23