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Is autosomal dominant inheritance universally accepted in AIS?

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  • #16
    Originally posted by Pooka1 View Post
    Would you say they possibly cherry-picked a reference with a rate close to theirs as opposed to represented the range of rates in the referred literature (which are a factor of 2 to 4 times higher)?
    That's certainly possible. But the study they used is pretty big. They screened over 1 million kids. I suppose one from Denmark would be the most appropriate. But their reference isn't an obscure reference to match their numbers.

    Lonstein JE, Bjorklund S, Wanninger MH, et al. Voluntary school screening
    for scoliosis in Minnesota. J Bone Joint Surg Am 1982;64:481–8.




    Originally posted by Pooka1 View Post
    Before the devil himself took over with fertility drugs and IVF, the MZ rate was about 1/3 that of the DZ rate IIRC. AFter, it would be lower. They got 0.48 MZ IIRC which is would be waaaaay too high. That actually shocked me that it wasn't low because in real life, I would say I have met at least as many folks who deny the (apparent) MZ status of their twins as who accept it. Researchers who aren't walking around meeting parents of twins will never have a clue about the extent of MZ denial and how that might screw up their questionnaire-based research (please pardon that possible oxymoron).

    So they discuss why their MZ rate is way off?
    I'm not sure why you think this is a negative. The clinical studies have MZ outnumbering DZ.
    Scoliosis in twins. A meta-analysis of the literature and report of six cases. - this study has 37 MZ and 31 DZ cases. What part of your argument am I missing here?


    Originally posted by Pooka1 View Post
    They deny MZ status. I think the reason is ignorance. They see different freckle locations or different hair whorls or different drug allergies and just assume the kids can't be identical. The Olsen twins of TV and movie fame have used some fallacious reasons for denying their obvious MZ status. All of these things (freckle pattern, etc.) and many more are completely specious.
    Why do you think they deny the MZ status?



    Originally posted by Pooka1 View Post
    I don't know how or why you conclude that.



    I am not sure how you know that more severe scoliosis has a measurable genetic component. It could be that the people with milder curves have more protective genes. Nobody knows.
    We had a similar exchange before. http://www.scoliosis.org/forum/showt...ht=#post116523 I re-read what your point was on the other thread about the 'measurable genetic component' and I understand the distinction you're making.

    But the oversampling of more severe curves is definitely the case. From that thread:

    I'm stating that they ARE more severe. The meta-analysis you posted confirms that. So the patients being counted in these studies, not only have scoliosis, but are being treated for it. Only 4 pairs of the monozygotic twins both had curves <20° (none of the dizygotic). The remainder had at least one, and most were both, curves >25°. So this is a decidedly biased group toward more severe curves. So the concordance rate being higher for more severe curves makes sense to me in light of the scoliscore data.

    It's true, what you're saying, that less severe curves might have a protective genetic link as well. Nobody knows for sure. But it doesn't take away from my point that, for many curves that are in need of clinical follow-up have a measurable genetic link. Thus, MZ twins needing clinical follow-up would have higher concordance since their scoliscore would be the same.

    Comment


    • #17
      Originally posted by skevimc View Post
      I'm not sure why you think this is a negative. The clinical studies have MZ outnumbering DZ.
      Scoliosis in twins. A meta-analysis of the literature and report of six cases. - this study has 37 MZ and 31 DZ cases. What part of your argument am I missing here?
      Two things:

      1. The fact that more MZ twins both have scoliosis compared to DZ twins in these studies in itself is some evidence that genetic inheritance is responsible (to the extent twins studies are even appropriate for a mid-line disorder - an open question per Ogilvie). But the concordance rate is too low compared to virtually all other studies.

      2. They apparently had no sets of DZ twins where both had scoliosis. That strains credulity since they had a few hundred sets of which about half self-identified as DZ. It seems like some folks thought if both twins had scoliosis and they were the same gender then they assumed they were MZ.

      Why do you think they deny the MZ status?
      The Olsen twins? I have read they think they are fraternal because one is taller than the other and they have different freckle patterns. I have heard others claim they have different teeth and needed to wear something so that the viewers of the TV show wouldn't notice. My kids who are MZ have different orthodontic problems and their teeth look different. All such reasons are stem to stern specious. You'll note they never claim they have DNA tests to prove they are fraternal.

      It's true, what you're saying, that less severe curves might have a protective genetic link as well. Nobody knows for sure. But it doesn't take away from my point that, for many curves that are in need of clinical follow-up have a measurable genetic link. Thus, MZ twins needing clinical follow-up would have higher concordance since their scoliscore would be the same.
      I agree that the few severe cases are atypical of the great run of milder cases and that the proper studies are weighted towards the severe cases. It is hard say whether what you gain in absolute facts about incidence of scoliosis and zygosity in a proper study is outweighed by that bias or not. It just seems to me that it still has to be far superior than the complete bunny grab bag of questioning folks about both zygosity and scoliosis which we know is probably wrong in the Danish study in terms of scoliosis and is definitely wrong in the case of zygosity. See this... (emphasis added)

      http://www.neoteny.org/neoteny/a/twins.html

      "The rate of monozygotic twinning is very much the same throughout the world: about 3 twin births per 1000. The dizygotic twinning rate, however, varies considerably. Thus, some older data showed that in Japan there was approximately 1 dizygotic twin birth out of 165, whereas in the northern countries of Ireland and Scotland the rate was about three times as high. The rates in northern Europe are generally of this order, and those in southern Europe are lower (Bulmer 1970).
      So apparently the rate of DZ twins in Denmark should have been (before the devil's fertility ways) about 3 in 165 or 18 in 1000 which is SIX(!) times the rate of MZ twins (which is constant). Thus if the Danish bunnies were accurate about their zygosity the rates would have been:

      MZ: 0.167
      DZ: 0.833

      But they got:

      MZ: 0.48(!)
      DZ: 0.52

      The problem is if that is so screwed up then what else is screwed up?
      Sharon, mother of identical twin girls with scoliosis

      No island of sanity.

      Question: What do you call alternative medicine that works?
      Answer: Medicine


      "We are all African."

      Comment


      • #18
        Originally posted by Pooka1 View Post

        Before the devil himself took over with fertility drugs and IVF,

        If you don't believe in God, you can't believe in the Devil. It's all science.
        Be happy!
        We don't know what tomorrow brings,
        but we are alive today!

        Comment


        • #19
          Originally posted by Pooka1 View Post
          Two things:

          1. The fact that more MZ twins both have scoliosis compared to DZ twins in these studies in itself is some evidence that genetic inheritance is responsible (to the extent twins studies are even appropriate for a mid-line disorder - an open question per Ogilvie). But the concordance rate is too low compared to virtually all other studies.
          No argument from me that these studies show a clear genetic influence.

          That the results, taken from a different population, don't agree with other studies does not immediately discount the study for me. Especially when the number of pairs in the Danish study outnumber all other studies. Of course, this doesn't mean the Danish study is the correct one based solely on numbers. But at this point, I think we're just arguing in circles, i.e. population based versus clinical based.

          Originally posted by Pooka1 View Post
          2. They apparently had no sets of DZ twins where both had scoliosis. That strains credulity since they had a few hundred sets of which about half self-identified as DZ. It seems like some folks thought if both twins had scoliosis and they were the same gender then they assumed they were MZ.
          I agree with this point. That there were no DZ pairs definitely suggests mis- or under-reporting. I'm not sure how the Danish twin registry verifies pairs' classification, i.e. are the people enrolled in the database just listed as 'twins' or are they listed as DZ or MZ? And if the later, then how is that verified? It would not seem to be really useful if that data were not accurate.


          Originally posted by Pooka1 View Post
          The Olsen twins?
          :> No... Just in general. Why would people deny their MZ status?


          Originally posted by Pooka1 View Post

          So apparently the rate of DZ twins in Denmark should have been (before the devil's fertility ways) about 3 in 165 or 18 in 1000 which is SIX(!) times the rate of MZ twins (which is constant). Thus if the Danish bunnies were accurate about their zygosity the rates would have been:

          MZ: 0.167
          DZ: 0.833

          But they got:

          MZ: 0.48(!)
          DZ: 0.52

          The problem is if that is so screwed up then what else is screwed up?
          But the number you are quoting are for the general population. The Danish study didn't report the overall MZ and DZ rate. Their 0.48 and 0.52 are for twins with both answering and with AIS. In this way, their zygosity rates are similar to other published studies. There's no reason to believe that the number of twins that responded to their survey did not fit ~0.17 MZ and ~0.83 DZ.

          Comment


          • #20
            Originally posted by rohrer01 View Post
            If you don't believe in God, you can't believe in the Devil. It's all science.
            I know. It's all nonsense. You are one of the only people ever to immediately see that what I wrote was a non-sequitor.

            The great run of religious folk think atheists BELIEVE in the the devil as far as I can tell.

            What can you say?
            Sharon, mother of identical twin girls with scoliosis

            No island of sanity.

            Question: What do you call alternative medicine that works?
            Answer: Medicine


            "We are all African."

            Comment


            • #21
              Originally posted by Pooka1 View Post
              I know. It's all nonsense. You are one of the only people ever to immediately see that what I wrote was a non-sequitor.

              The great run of religious folk think atheists BELIEVE in the the devil as far as I can tell.

              What can you say?
              Excuse me...but why do you think you're the only one allowed to talk about religion on this site? You shut up anyone else. Please take your trash talk to your fellow new atheist Christian bashing sites and leave this site for the discussion of scoliosis and other interesting science discoveries.

              Comment


              • #22
                Originally posted by skevimc View Post
                It would not seem to be really useful if that data were not accurate.
                There's an understatement. :-)

                :> No... Just in general. Why would people deny their MZ status?
                Are you asking me to do psychology? Without a net? :-)

                Okay then! I think most cases are ignorance that MZ twins can differ in height, teeth, scolsiosi curve type, hair whorl direction, handedness, hair tone freckle pattern, drug allergies, etc. etc. and STILL be MZ twins. My MZ twins differ on many of these points and probably more.

                A few cases I think are just due to the strangeness of having identical individuals so they deny it and hang their hat on anything to do so. Just a guess.

                But the number you are quoting are for the general population. The Danish study didn't report the overall MZ and DZ rate. Their 0.48 and 0.52 are for twins with both answering and with AIS. In this way, their zygosity rates are similar to other published studies. There's no reason to believe that the number of twins that responded to their survey did not fit ~0.17 MZ and ~0.83 DZ.
                Ah that's a misunderstanding. I was asking you about the entire population of twins enrolled in the Danish registry, not the few hundred in this study. I wanted to use that as a way to gage the GIGO-ness of zygosity in the study.

                I certainly would expect the numbers to be at least 50-50 for both MZ twins having scoliosis and more likely 75-25.

                So basically about half of the almost 300 sets (is that correct?) in this AIS study were DZ twins and in no case did both have AIS? That's lower than what is known for any sibling-sibling-pair which is on the order of ~11-33%. You would expect at least 15 sets would have both DZ twins with AIS.

                Are you ready to toss the study yet?
                Sharon, mother of identical twin girls with scoliosis

                No island of sanity.

                Question: What do you call alternative medicine that works?
                Answer: Medicine


                "We are all African."

                Comment


                • #23
                  Originally posted by Ballet Mom View Post
                  interesting science discoveries.
                  Science and religion are not compatible.
                  Sharon, mother of identical twin girls with scoliosis

                  No island of sanity.

                  Question: What do you call alternative medicine that works?
                  Answer: Medicine


                  "We are all African."

                  Comment


                  • #24
                    Originally posted by Pooka1 View Post
                    Science and religion are not compatible.
                    What an ass.

                    Comment


                    • #25
                      Originally posted by Ballet Mom View Post
                      What an ass.
                      I'd like to apologize. I'm sorry you called me an ass. :-)
                      Sharon, mother of identical twin girls with scoliosis

                      No island of sanity.

                      Question: What do you call alternative medicine that works?
                      Answer: Medicine


                      "We are all African."

                      Comment


                      • #26
                        And by the way, it's just my opinion!
                        Sharon, mother of identical twin girls with scoliosis

                        No island of sanity.

                        Question: What do you call alternative medicine that works?
                        Answer: Medicine


                        "We are all African."

                        Comment


                        • #27
                          Originally posted by Pooka1 View Post

                          So basically about half of the almost 300 sets (is that correct?) in this AIS study were DZ twins and in no case did both have AIS? That's lower than what is known for any sibling-sibling-pair which is on the order of ~11-33%. You would expect at least 15 sets would have both DZ twins with AIS.
                          Based on the other studies, you are correct. But again, other studies were clinic based not population based.


                          Originally posted by Pooka1 View Post
                          Are you ready to toss the study yet?
                          No. There's a lot more in the study than what's printed in the abstract.

                          Comment


                          • #28
                            Originally posted by Pooka1 View Post
                            Science and religion are not compatible.
                            Pooka1,
                            Just remember, not everyone feels that way. That is your opinion. I have found no conflicts in what I believe and science. I have no problem believing that the Earth is ~5.4 billion years old. Scoliosis is the result of genetic mutation and/or negative "environmental" causes. That is science. We don't need to bash other people's ideas when they don't pertain to the discussion at hand. Just remember that most of the world's greatest scientists were also theologians, Sir Isaac Newton, for example. Many were hunted down and martyred by the "Churches" for heresy, when, in fact, what they discovered had no conflict with the Bible, but had great conflict with Church Doctrine, which by the way, was mostly politically motivated. It is statements like this that start the arguments that are weaved throughout legitimate threads. Besides respecting other people, no matter what they "believe", even if it is nonsense, promotes peace. Making sweeping statements as you do, is far less convincing than showing the scientific process. It just makes you look like a hater, which I don't believe you are. I can honestly say, from reading your posts, that you really do care about people and you are a genuinely nice person. That's my opinion, anyway.
                            Be happy!
                            We don't know what tomorrow brings,
                            but we are alive today!

                            Comment


                            • #29
                              Originally posted by rohrer01 View Post
                              Pooka1,
                              Just remember, not everyone feels that way. That is your opinion. I have found no conflicts in what I believe and science.
                              The conflict is in claiming there are other ways to know besides evidence. Either you admit evidence is the only way to know a damn thing (science) or you don't admit it (not science). It is fine to say you believe something just because it makes you feel good.

                              It is no coincidence that belief in personal gods goes down as achievement in science goes up culminating in ~93% of the National Academy of Science members (cream fo the cream) rejecting the idea of a personal god.

                              I have no problem believing that the Earth is ~5.4 billion years old.
                              I do because the earth is ~4.55 billion years old. :-)

                              Scoliosis is the result of genetic mutation and/or negative "environmental" causes. That is science. We don't need to bash other people's ideas when they don't pertain to the discussion at hand. Just remember that most of the world's greatest scientists were also theologians, Sir Isaac Newton, for example. Many were hunted down and martyred by the "Churches" for heresy, when, in fact, what they discovered had no conflict with the Bible, but had great conflict with Church Doctrine, which by the way, was mostly politically motivated. It is statements like this that start the arguments that are weaved throughout legitimate threads.
                              Newton is widely regarded as the most productive thinker ever and yet he had some demonstrably wacky ideas. Other famous scientists also held some very wacky beliefs. The point is they didn't let it contaminant their science. Were they living today they might be in the 7% of the National Academy members who don't reject a personal god or they might just be in the 93% who do since society has advanced in thought since their time.

                              Besides respecting other people, no matter what they "believe", even if it is nonsense, promotes peace. Making sweeping statements as you do, is far less convincing than showing the scientific process. It just makes you look like a hater, which I don't believe you are. I can honestly say, from reading your posts, that you really do care about people and you are a genuinely nice person. That's my opinion, anyway.
                              Well I am of the opinion that you can and SHOULD criticize wacky beliefs that harm innocent people like laws against gay marriage and embryonic stem cell research and limiting choice in abortion of non-viable fetuses. People are not their ideas and these are not criticisms of the persons. The problem is folks can't separate themselves from what they believe. I do NOT respect the social taboo against criticizing sacred beliefs because if people don't do that, society can't advance and innocent people will continue to be harmed. All these things are just ideas and they should all be on the table for criticism.
                              Sharon, mother of identical twin girls with scoliosis

                              No island of sanity.

                              Question: What do you call alternative medicine that works?
                              Answer: Medicine


                              "We are all African."

                              Comment


                              • #30
                                Originally posted by Pooka1 View Post

                                I do because the earth is ~4.55 billion years old. :-)




                                However old the earth is, neither of us were there when it was formed...
                                Respecting someone and forcing a harmful act or idea on someone are two different things. You believe what you want, I believe what I want and we can still be good neighbors, others believe what they want, let's all get along. I happen to base my beliefs on facts, despite what you may think, and am very interested in science not pseudoscience. I would never publicly attack you for your beliefs or call you stupid if you didn't concur with mine. Discussions are another matter. But unfortunately people do feel attacked and even leave the forum, which is sad. You have a lot to offer and more people would listen if you would just tone it down a bit. This is a place where people with scoliosis or family with scoliosis come for support and information. Let the like-minded people "support" each other and the ones that want straight facts about scoliosis related topics come here without fear of being attacked. PLEASE.
                                Be happy!
                                We don't know what tomorrow brings,
                                but we are alive today!

                                Comment

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