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mnhnhyouh

Joined: 21 Nov 2006 Location: The Middle Kingdom
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Posted: Thu May 15, 2008 5:48 pm Post subject: Korean genetic susceptiblity to CJD |
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So I have been trying to understand the whole mad cow thing. I have been doing some reading, first about CJD, and vCJD, and prions, and finally Korean susceptibility to this disease.
I read the op-ed piece about this in today's Korea Herald, and thought the genetic thing was probably bogus, so went searching, and then hit the papers. There are two, both with the lead author in common, both with big lists of authors (as genetic papers tend to have) and both in quality journals.
Links here
http://www.nature.com/ejhg/journal/v13/n9/full/5201460a.html#bib24
http://springerlink.metapress.com/content/51h1j81h80hjrdtf/
It is the second of these papers that has the evidence, limited though it is, unfortunatly I can only find the abstract. Here is the last line in the abstract:
| Polymorphisms of the prion protein gene (PRNP) in a Korean population, Byung-Hoon Jeong et. al wrote: |
The data of PRNP polymorphism at codon 219 suggest that Koreans may be more sensitive to sporadic CJD than the Japanese population. |
I am not sure, but it may be that this line:
| Polymorphisms of the prion protein gene (PRNP) in a Korean population, Byung-Hoon Jeong et. al wrote: |
| In addition, the genotype frequency of heterozygotes (12.7%) at codons 129 or/and 219 was significantly lower in Koreans than in people from Great Britain (chi2=89.52, P<0.0001). |
means that Koreans are less susceptible than Europeans.
I have two problems with this being used as evidence that Koreans are more susceptible to eating prion infected beef:
1) There data relates to sporadic CJD and that is caused (I think) by genetic defects....
| wikipedia wrote: |
People can also acquire CJD genetically through a mutation of the gene that codes for the prion protein(PRNP). This only occurs in 5-10% of all CJD cases. |
2) There is little data out there to base these decisions on.
I was sure that this was a bogus claim put out there by the media. Now that I have read this (while some of my degrees are in biology my understanding of genetics is poor at best) I am less confident that this is just rubbish. It is easy to concieve that this genetic marker indicates a greater susceptibility to aquiring CJD from eating infected beef.
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Easter Clark

Joined: 18 Nov 2007 Location: Hiding from Yie Eun-woong
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Posted: Thu May 15, 2008 6:19 pm Post subject: |
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My gf said that Koreans are more susceptible to the disease because of Korean genes. I asked her if she was sure Koreans were human!
Actually, I think the reason Koreans are maybe more likely to get the disease is because they eat the parts of the cow that we would normally throw away, like the brains, organs, and backbones. |
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Yu_Bum_suk

Joined: 25 Dec 2004
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Posted: Thu May 15, 2008 6:26 pm Post subject: |
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| Didn't the Korean professor who wrote the article live in the US for a while where he regularly ate US beef? |
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howie2424

Joined: 09 Jan 2003
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Posted: Thu May 15, 2008 6:43 pm Post subject: |
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The actual author of the paper which suggested a genetic susceptibility to the disease was Prof. Yong-Sun Kim of Hallym University. If I understand the situation correctly, it was his paper that was cited in the TV documentary that incited the present hysteria over US beef import resumption. When the TV show aired he was out of the country and returned last Friday to a waiting throng of Korean reporters. When asked about his paper he said this;
"Genetics is a factor, but we cannot conclude that genes alone can determine the cause of a disease. It will take more time. A comparative study is also necessary. Just because 94 per cent of Koreans have MM genotype, it is too dangerous to talk about risk." When asked why his paper was being cited as support for the argument that Koreans were more susceptible to the disease Prof. Kim said "I am very perplexed by the situation."
Now I'm no scientist and I don't claim to understand what these guys are talking about but based on the above Prof. Kim, the guy in the know about this seems to be saying that this is just a theory based on anecdotal evidence and further research is necessary before any reliable conclusions can be drawn. Not that empirical evidence or sound science will get in the way of, or otherwise concern the millions of lemmings here who fret about US beef that they never consume while puffing away on their 25th smoke of the day.
Wish I could find a link to the actual interview with him from last Saturday's Joong Ang Ilbo but these links summarize his remarks.
http://www.koreatimes.co.kr/www/news/nation/2008/05/123_24077.html
http://english.chosun.com/w21data/html/news/200805/200805090017.html |
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mnhnhyouh

Joined: 21 Nov 2006 Location: The Middle Kingdom
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Posted: Thu May 15, 2008 6:48 pm Post subject: |
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| howie2424 wrote: |
| The actual author of the paper which suggested a genetic susceptibility to the disease was Prof. Yong-Sun Kim of Hallym University. |
These are the papers I linked to above, I think. He is the last author cited on the papers. If the authorship order is like those in the west either they are all his students (there seem too many for that) or he is the minor author.
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Cornfed
Joined: 14 Mar 2008
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Posted: Thu May 15, 2008 6:48 pm Post subject: |
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| On the face of it, it seems strange to draw any conclusions on the heritability of a disease when no-one really knows the cause. The popular theory is that it is caused by a protein in a mutant conformation - a "prion". This seems like far fetched nonsense to me. A more plausable cause might be a sarcoplasmic bacterial infection, in which case genetics probably plays little part. |
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doggyji

Joined: 21 Feb 2006 Location: Toronto - Hamilton - Vineland - St. Catherines
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Posted: Thu May 15, 2008 7:43 pm Post subject: Re: Korean genetic susceptiblity to CJD |
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| mnhnhyouh wrote: |
| Polymorphisms of the prion protein gene (PRNP) in a Korean population, Byung-Hoon Jeong et. al wrote: |
| In addition, the genotype frequency of heterozygotes (12.7%) at codons 129 or/and 219 was significantly lower in Koreans than in people from Great Britain (chi2=89.52, P<0.0001). |
means that Koreans are less susceptible than Europeans. |
Shouldn't it be the opposite? The frequency of heterozygotes is lower. In other words, the frequency of homozygotes (which are hypothesized to cause susceptiblility) is higher in Koreans than in people from GB.
| Easter Clark wrote: |
| Actually, I think the reason Koreans are maybe more likely to get the disease is because they eat the parts of the cow that we would normally throw away, like the brains, organs, and backbones. |
This has been mentioned a lot as well. In the States, those parts are worth nothing even if they are from the best cattle. Korea can be an attractive market for them.
| Yu_Bum_suk wrote: |
| Didn't the Korean professor who wrote the article live in the US for a while where he regularly ate US beef? |
Maybe he didn't really eat US Commercial beef.
By the way, wouldn't it be better to pile up information here rather than keep making new threads?  |
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