4 ms·

This is potentially good news. My sister has schizophrenia, and not a day passes when I don't worry about my 3 year-old son being diagnosed with this terrible d

by mcone 12y ago

This is potentially good news. My sister has schizophrenia, and not a day passes when I don't worry about my 3 year-old son being diagnosed with this terrible disease. I'm not a scientist or an engineer, so maybe somebody who has read the published article can help me out here. I wonder what the percentages mean. How do they determine whether or not someone has a 73% chance of being diagnosed with the disease? And what does that mean exactly? On the other hand, this research raises even more questions. For instance, I wonder what steps you could take to help a child with, say, a 60% chance of being diagnosed with schizophrenia? Are the genes like switches, in the sense that certain environmental variables can flip them on and off? If so, I guess there is a lot that could be done to help someone who has a good chance of being diagnosed.

javert 12y ago
This is anecdotal, but having known schizophrenics, make sure your son stays away from drugs (e.g. marajuana and the like). I had a close friend who attributed his very bad schizophrenic symptoms to an increase in drug use (specifically marajuana). Correlation does not imply causation, but in this case, it's probably not worth the risk.
- vezzy-fnord 12y ago
  Narcotics will serve as catalysts for the symptoms. If they're present, they'll manifest themselves organically, regardless.
  - javert 12y ago
    By "serve as catalysts" do you mean "make more severe," "make more frequent," "make appear earlier in life," or perhaps all of the above, or perhaps something different?
    - bbrian 12y ago
      I think he means "make appear earlier in life". > Several studies have suggested that regular, long-term cannabis use is one of a number of environmental factors that, in combination with certain genetic predisposing factors, may significantly increase a young individual’s chance of experiencing psychosis and developing schizophrenia. However, numbers of people being diagnosed with schizophrenia remained stable over time during which the number of cannabis users increased and average strength rose significantly. http://www.drugscience.org.uk/blog/2013/10/24/think-cannabis-harmless-no-does-anyone-what-about-propagating-drug-hysteria-harmless/ http://www.drugscience.org.uk/blog/2013/10/24/think-cannabis...
tjradcliffe 12y ago
This work investigates what are called "single nucleotide polymorphisms" (SNPs, pronounced "snips"), which identify genes that make slightly different forms of the same protein (the most common result of a SNP is to have swap one amino acid for another in a protein, which may change its shape a little so it won't work quite as well under some circumstances, or may bind a little more heavily to one site vs another.) The percentages mean that if you take 100 people with a given combination of SNPs, 73 of them will get schizophrenia. People without that combination will have a much lower chance. The good news for you and your son is that because they have identified multi-gene effects, the odds of you or your son having all the same SNPs as your sister is very low. You and your sister share half your DNA, so if there are ten genes involved, each with a 50/50 chance of being shared, that's a 1 in 1024 chance (2^10). For your son it's one in a million (unfortunately I can't tell from the article or the journal abstract how big the SNP sets involved actually are, but given the difficulty in finding them I'd expect more than four or five SNPs per set.) With regard to your other questions, the honest answer is: nobody knows, although there will be any number of people trying to sell you on unproven solutions, mostly based on the demon of the moment. Twenty years ago it might have been red meat. Five years ago it would have been gluten. Today it would be refined sugars. Tomorrow it will be something else. The only thing we can be sure of is that the promoters will be smug, self-assured and self-deluded (or dishonest, but I think self-delusion is more common).
- danieltillett 12y ago
  I would be very wary of putting number on the op child's risk of developing schizophrenia. You really need to know the frequency of the various snips in the population to know this. The most we can say right now is that the OP's son has an unknown higher risk than someone in the general population. The good news is we should soon have a better idea of what this risk is.
- gwern 12y ago
  > unfortunately I can't tell from the article or the journal abstract how big the SNP sets involved actually are, but given the difficulty in finding them I'd expect more than four or five SNPs per set. Table 1 ( https://pdf.yt/d/rErZm8HUluBbj8xu https://pdf.yt/d/rErZm8HUluBbj8xu / https://dl.dropboxusercontent.com/u/5317066/2014-arnedo.pdf https://dl.dropboxusercontent.com/u/5317066/2014-arnedo.pdf / https://www.sendspace.com/file/ht7shm https://www.sendspace.com/file/ht7shm ) list characteristics of the sets; they range from a low of 3 to a high of 32, with associated risks of 70 - 100% (!). The size of the sets with a risk of schizophrenia between 90% and 100% is 11/11/19/4/6/3/10/6/9. (SNP set 87\_76 is the one with just 3 SNPs and a risk of 95%. Very nasty.) Unfortunately I don't think this risk information is enough to to calculate how much predictive value SNPs would have for someone undiagnosed since you'd need to know how many healthy people have these SNP sets as well? But I'm sure the genomics hobbyists and anyone with 23andme data are probably looking closely at the paper and trying to extract risk estimates...

by mcone 12y ago

javert 12y ago

This is anecdotal, but having known schizophrenics, make sure your son stays away from drugs (e.g. marajuana and the like). I had a close friend who attributed his very bad schizophrenic symptoms to an increase in drug use (specifically marajuana). Correlation does not imply causation, but in this case, it's probably not worth the risk.

vezzy-fnord 12y ago
Narcotics will serve as catalysts for the symptoms. If they're present, they'll manifest themselves organically, regardless.
- javert 12y ago
  By "serve as catalysts" do you mean "make more severe," "make more frequent," "make appear earlier in life," or perhaps all of the above, or perhaps something different?
  - bbrian 12y ago
    I think he means "make appear earlier in life". > Several studies have suggested that regular, long-term cannabis use is one of a number of environmental factors that, in combination with certain genetic predisposing factors, may significantly increase a young individual’s chance of experiencing psychosis and developing schizophrenia. However, numbers of people being diagnosed with schizophrenia remained stable over time during which the number of cannabis users increased and average strength rose significantly. http://www.drugscience.org.uk/blog/2013/10/24/think-cannabis-harmless-no-does-anyone-what-about-propagating-drug-hysteria-harmless/ http://www.drugscience.org.uk/blog/2013/10/24/think-cannabis...

tjradcliffe 12y ago

This work investigates what are called "single nucleotide polymorphisms" (SNPs, pronounced "snips"), which identify genes that make slightly different forms of the same protein (the most common result of a SNP is to have swap one amino acid for another in a protein, which may change its shape a little so it won't work quite as well under some circumstances, or may bind a little more heavily to one site vs another.) The percentages mean that if you take 100 people with a given combination of SNPs, 73 of them will get schizophrenia. People without that combination will have a much lower chance. The good news for you and your son is that because they have identified multi-gene effects, the odds of you or your son having all the same SNPs as your sister is very low. You and your sister share half your DNA, so if there are ten genes involved, each with a 50/50 chance of being shared, that's a 1 in 1024 chance (2^10). For your son it's one in a million (unfortunately I can't tell from the article or the journal abstract how big the SNP sets involved actually are, but given the difficulty in finding them I'd expect more than four or five SNPs per set.) With regard to your other questions, the honest answer is: nobody knows, although there will be any number of people trying to sell you on unproven solutions, mostly based on the demon of the moment. Twenty years ago it might have been red meat. Five years ago it would have been gluten. Today it would be refined sugars. Tomorrow it will be something else. The only thing we can be sure of is that the promoters will be smug, self-assured and self-deluded (or dishonest, but I think self-delusion is more common).

danieltillett 12y ago
I would be very wary of putting number on the op child's risk of developing schizophrenia. You really need to know the frequency of the various snips in the population to know this. The most we can say right now is that the OP's son has an unknown higher risk than someone in the general population. The good news is we should soon have a better idea of what this risk is.
gwern 12y ago
> unfortunately I can't tell from the article or the journal abstract how big the SNP sets involved actually are, but given the difficulty in finding them I'd expect more than four or five SNPs per set. Table 1 ( https://pdf.yt/d/rErZm8HUluBbj8xu https://pdf.yt/d/rErZm8HUluBbj8xu / https://dl.dropboxusercontent.com/u/5317066/2014-arnedo.pdf https://dl.dropboxusercontent.com/u/5317066/2014-arnedo.pdf / https://www.sendspace.com/file/ht7shm https://www.sendspace.com/file/ht7shm ) list characteristics of the sets; they range from a low of 3 to a high of 32, with associated risks of 70 - 100% (!). The size of the sets with a risk of schizophrenia between 90% and 100% is 11/11/19/4/6/3/10/6/9. (SNP set 87\_76 is the one with just 3 SNPs and a risk of 95%. Very nasty.) Unfortunately I don't think this risk information is enough to to calculate how much predictive value SNPs would have for someone undiagnosed since you'd need to know how many healthy people have these SNP sets as well? But I'm sure the genomics hobbyists and anyone with 23andme data are probably looking closely at the paper and trying to extract risk estimates...