"Why doesn't she age?"

Discussion in 'Biology & Genetics' started by PieAreSquared, Jun 24, 2009.

  1. Xylene Valued Senior Member

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    It's a tragic business--I noticed when I read the article that one of the doctors said she was aging, but that the aging process was 'out of sync'. It occurred to me that she could be suffering from a very basic fault with the homeobox genes. The hox genes determine the physical makeup of the different parts of the body--skin colour, hairyness, limb-length etc. There must be a mechanism in normal growth by which the different parts of the body all age at the same pace, and there must be genes that contol this overall aging process. It seems that the controlling gene (or set of genes) that oversees this combined change, is missing in these people. This is my best guess at the problem...
     
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  3. PieAreSquared Woo is resistant to reason Registered Senior Member

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  5. Xylene Valued Senior Member

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  7. Hercules Rockefeller Beatings will continue until morale improves. Moderator

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    Good try. :thumbsup: But I very much doubt Hox gene mutations are involved. Hox genes act early in embryonic development to establish the basic body plan and segments. All those things you mentioned - skin colour, hairyness, limb-length – are determined later in development (once the body plan has been established) by a variety of other genes. She’s seemingly normally formed, just not developing properly as a teenager. Organisms with Hox gene abnormalities tend to develop gross malformations during embryonic development.
     
  8. Nasor Valued Senior Member

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    That's actually the biggest question that the scientists who are following her case are interested in answering. One theory of aging is that it's related to the some "master control" mechanism that causes organisms to grow and mature continuing to be active after the organism has reached maturity and doesn't actually need to grow or develop any more. There is some evidence to support that theory; for example, there's a strong correlation between how quickly people reach sexual maturity and how quickly they begin to experience the symptoms of old age. There are also correlations between raw growth rates and aging rates later in life. Under that theory, it might be possible to greatly delay the onset of "old age" by somehow halting the mechanism responsible for growth and maturity in early adulthood.

    The fact that this sort of disorder is even possible seems like evidence that such a master control mechanism might at least exist, and that it is indeed possible to have someone develop to a certain point and them switch the mechanism off, halting or slowing further development. She was found to be growth hormone deficient, but nothing happened when they started giving her growth hormones, even though so far as they can tell she isn't non-receptive to it in any known way; implying that there was some higher-level switch that was responsible for both the triggering of growth hormone production, and also the triggering of other factors that need to be "switched on" before growth hormones can cause anything to happen.

    Now age researchers are curious to see whether her apparent slow development will be correlated to a slow rate of aging, or if she'll begin to develop geriatric problems at the same time as everyone else, albeit in the body of a child.
     
  9. Xylene Valued Senior Member

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    I heard recently that someone had worked out which genes were involved in the progress of progeria, ie the onset of premature aging--which is oten associated with various types of dwarfism...could this syndrome from which the girl is suffering be somehow associated with the genes that cause progeria?:scratchin:

    http://en.wikipedia.org/wiki/Progeria
     
  10. Hercules Rockefeller Beatings will continue until morale improves. Moderator

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    I very much doubt it. I’m not aware of any such occurrence in mammals. Calorie restriction or genetic engineering can extend the lifespan of mammals but always by only small fractions of a lifetime.


    Yes, this will almost certainly be the case.
     
    Last edited: Jun 27, 2009
  11. Hercules Rockefeller Beatings will continue until morale improves. Moderator

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    I remember reading that mutations in extracellular matrix genes were the cause of progeria. eg. laminin, fibronectin, etc


    Again, I doubt it. Some sort of gain-of-function mutation in an ECM gene might result in a more stable or “better functioning” ECM protein, but this wouldn’t let the cells escape their genetic aging program. Our cells are programmed to die – we can’t escape that.
     
  12. Nasor Valued Senior Member

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    No, they checked all the genes associated with progeria and other "accelerated aging" diseases, and they're all normal. Pretty much any explanation you could think of, they checked - that's part of what makes the whole thing so puzzling. Apparently there is some sort of currently-unknown, very high level control mechanism that regulates virtually all aspects of growth and development that is malfunctioning in her.
     
  13. tuberculatious Banned Banned

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