Why Jaundice is Seen in Classic Galactosemia?
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- Опубліковано 3 сер 2016
- In this video the biochemical mechanism for the presence of jaundice in classic galactosemia is explained. Classic galactosemia is due to defect in galactose 1-phosphate uridyltransferase enzyme. this leads to elevation of galactose 1-phosphate thereby trapping the inorganic phosphate which can lead to fasting hyperglycemia, mental retardation. Elevated galactose 1-phosphate acts negatively on phosphoglucomutase enzyme and decrease the availability of glucose 1-phosphate leading to decreased UDP-glucose and consequently decreased UDP-glucoronate. Decreased availability of UDP-glucoronate lead to decreased activity of UGT1A1. Decreased activity of UGT1A1 lead to decreased conjugation of bilirubin and hence elevated levels of unconjugated bilirubin leading to jaundice. bilateral cataract seen in classic galactosemia is due to increased galactitol formation.
You can take a look at my video on galactose metabolism and galactosemia in the link below
• Galactose Metabolism a...
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Key words:
classic galactosemia
galactosemia
non classic galactosemia
jaundice
hepatomegaly
mental retardation
bilateral cataract
galactitol
cataract
UDP-glucoronate
glucoronate
bilirubin
conjugated bilirubin
unconjugated bilirubin
conjugation
hepatic conjugation
phosphoglucomutase
glucose 1 phosphate
udp glucose
GALT
galactokinase
uridyltransferase
Mungli
usmle
step1
PG entrance
MD biochemistry
biochemistry
review video
why jaundice
I haven´t seen a better explanation of galactosemia an jaundice than this, greetings from Mexico.
😃😃
Thank you for the video sir. It was very helpful.
Thanks for useful information
nicely explained...thanx sir
Great lecture sir
Thank you so much, that was really helpful 👍🏻👍🏻
You are most welcome. I'm glad this video was helpful to you.
thank you so much!
very nicely explained
Thank you.
thank u so much this helped so much :))))
May God bless u
explained well
tq
Thank you.
Very nice explanation. Just one question sir. In your video you said that galactosemia causes UNCONJUGATED BILIRUBINEMIA. However most sources would say that galactosemia causes CONJUGATED HYPERBILIRUBINEMIA. What do you think is the explanation for that sir? Thank you.
Came here for this exact same reason and had the same question lol.... thanks for posting!
After the increase in unconjugated bilirubin, there is no defect in its conjugation. This is why classic galactosemia is thought to primarily cause direct hyperbilirubinemia. However, further accumulation of unconjugated bilirubin may exceed the liver's conjugating ability (especially in a newborn), leading to a rise in both conjugated & unconjugated bilirubin. This is why UpToDate says that classic galactosemia can present with direct AND/OR indirect hyperbilirubinemia.
Thank you so.much sir
You are most welcome.
Thankyou! Helped a lot!♥️😁 ...just happened to notice the comments...what is the hm park guy going on about sir? Could you please explain what he is trying to say?
Thank You very much Professor Mungli. I would want do know how galactosemia determ fat degenaration, thank you!
Thanks sir..
You are welcome.
Thank you very much Dr. Mungli 👌🏻❤
Very informative. But why does the raised unconjugated bilirubin lead to jaundice?
Unconjugated bilirubin is hydrophobic and diffuse into tissues to stain, specially elastic tissue.
year, nice. Except speed. This information can fit to 0.30 min video with 100 words/min rate
True, but it could have been much faster. Nevertheless, thank you for the feedback.
LOL This cannot be more wrong! Although galactosemia can cause both indirect and direct hyperbilirubinemia, it most commonly present as direct hyperbilirubinemia, not indirect hyperbilirubinemia as mentioned in this video. You can never explain this with your concept.
I'm explaining the mechanism of initial elevation of unconjugated bilirubin in classic galactosemia. Once the liver pathology sets in, both types of bilirubin are elevated. You can watch my video on pre-hepatic, hepatic and post-hepatic jaundice to why do you see elevated levels of both types of bilirubin in hepatic jaundice.
Kindly read the excerpt from one of the article from Journal of perinatology.
Early hyperbilirubinemia of galactosemia may be predominantly unconjugated, and can become conjugated. A hepatic origin is still plausible, as bilirubin conjugation may be inhibited by galactose-1-phosphate or other toxic metabolites that accumulate in galactosemia.
www.nature.com/articles/jp2009136
Hope this helps.
What I want to point out is that yours is just a hypothesis, not a well-established theory.
Accumulation of any toxic material in the liver can cause hepatic dysfunction which may lead to both indirect and direct hyperbilirubinemia.
In this concept, the inhibiton of UGT becomes an unnecessary step.
The article you mentioned above is a case-report, which in turn indicates that galactosemia rarely present as indirect hyperbilirubinemia in clinical situations.
As I know, there are numerous different hypotheses for the pathophysiology of jaundice in galactosemia. I wish I could see the article/textbook you used for reference.
I generally do not assume things while I teach. I have either referred to text or reference book or a indexed peer reviewed journal. Since you insist on giving the text reference, here is the reference from a book Advances in Clinical Chemistry the link I have given below. I will paste the link in separate comment. Please check your spam folder if UA-cam detects it as spam. I'm also sharing links from research articles too.
link for textbook Advances in Clinical Chemistry
books.google.com/books?id=g7bgewdepRcC&pg=PA21&lpg=PA21&dq=galactose+1+phosphate+inhibition+on+phosphoglucomutase&source=bl&ots=JVKFb_zpAw&sig=DsJ4D-02Tl5CsrQDCmNC2XdKR1Y&hl=en&sa=X&ved=0ahUKEwjugcyxm8nZAhUCCawKHZukDcUQ6AEIYTAI#v=onepage&q=galactose%201%20phosphate%20inhibition%20on%20phosphoglucomutase&f=false
www.ncbi.nlm.nih.gov/pubmed/18421797
Bkwaas
Omg your voice really drags, so boring and monotone, I struggled to stay awake!
Sorry about that, it is probably because I used iPad to make this video rather white board. Thank you for the feedback.