brown eye and green-grey eye

Discussion in 'Health and medical' started by Craig Feinstein, Feb 25, 2004.

  1. I tried to find a genetics chatroom but I thought maybe someone could answer me. My son who is 2
    months old has one brown eye and one green-grey eye. It turns out my wife's aunt has the same thing.
    Is this common? This gene would probably be recessive, so does this mean I'm also a carrier? I have
    brown eyes and my wife has green eyes. My son's twin sister has two lighter brown eyes.

    I think David Bowie has this and I heard Alexander the Great also had this. Any other famous people?

    Craig
     
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  2. Wirt Atmar

    Wirt Atmar Guest

    Craig asks:

    >I tried to find a genetics chatroom but I thought maybe someone could answer me. My son who is 2
    >months old has one brown eye and one green-grey eye. It turns out my wife's aunt has the same
    >thing. Is this common? This gene would probably be recessive, so does this mean I'm also a carrier?
    >I have brown eyes and my wife has green eyes. My son's twin sister has two lighter brown eyes.
    >
    >I think David Bowie has this and I heard Alexander the Great also had this. Any other
    >famous people?

    This is a recurring question here on this newsgroup. Enclosed below is how I answered the question
    approximately four years ago:

    ======================================

    From: Wirt Atmar ([email protected]) Subject: Re: Human eye -- weird pigmentation Newsgroups:
    sci.bio.evolution Date: 2000/01/05

    Louann Miller asks:

    >Just a quick question, probably not controversial in any way but an oddity I've been wondering
    >about over time.
    >
    >I had a college classmate whose left eye was two different colors. The iris was divided into two
    >distinct half-circle shapes, blue on one side and light brown on the other. The dividing line
    >(vertical) was sort of greenish. Her right eye was the same shade of blue as the blue half of her
    >left eye.
    >
    >She said it had always been like that, it didn't hurt, and she didn't have any vision problems. I
    >didn't think to ask if anyone else in the family had it. It was weird enough to be memorable. I've
    >never met or heard of anyone else with the same condition (except a fictional character in George
    >MacDonald Frazier's "Flashman" novels, which hardly counts.)
    >
    >So: what is the name of this condition? Is it genetic or something in the prenatal environment? Is
    >is related to the more common condition where a person (or a cat or dog) can have each eye a single
    >different color? Etc. I'm interested in any information anyone has.

    The general morphological description is called "heterochromia irides", which means nothing more in
    plain English than "differently colored irises."

    In that, the condition is not normal, and even though the bearer may be completely non-impeded by
    its presence, it is a genetic "defect." However, it is often more serious than that. Heterochromia
    irides, especially when it refers to eyes of two different colors -- but sometimes in eyes where one
    iris is either splotchy with both blue and green/brown colors or evenly divided into two differently
    colored hemispheres -- is a primary diagnostic character for Waardenburg Syndrome (see:
    http://www.icondata.com/health/pedbase/files/WAARDENB.HTM ), a developmental abnormality that is
    common to many large mammals, exactly as you suggest.

    Humans, cats and dogs that exhibit eye colors that are quite markedly differently colored, where one
    eye is blue and the other green or brown, are often mildly to profoundly deaf. The abnormality
    appears to be due to a point defect in the pax-3 gene, a homeo box gene that is widely expressed
    during early embryogenesis, thus explaining the wide range of effects that the gene has.

    Waardenburg Syndrome is inherited dominantly, however it is suspected that only perhaps 20% of those
    bearing some form of the defect are actually aware of it, its effects being so mild in most people.

    More information can be found at:

    http://www.boystown.org/deafgene.reg/waardsx.htm

    Wirt Atmar

    ======================================

    Wirt Atmar
     
  3. Craig Feinstein wrote:

    > I tried to find a genetics chatroom but I thought maybe someone could answer me. My son who is 2
    > months old has one brown eye and one green-grey eye. It turns out my wife's aunt has the same
    > thing. Is this common? This gene would probably be recessive, so does this mean I'm also a
    > carrier? I have brown eyes and my wife has green eyes. My son's twin sister has two lighter
    > brown eyes.
    >
    > I think David Bowie has this and I heard Alexander the Great also had this. Any other
    > famous people?

    My dad's eyes were like that. It seems much more "special" than common.

    --Jeff

    --
    A man, a plan, a cat, a canal - Panama!

    Ho, ho, ho, hee, hee, hee and a couple of ha, ha, has; That's how we pass the day away, in the merry
    old land of Oz.
     
  4. Ron Okimoto

    Ron Okimoto Guest

    Craig Feinstein wrote:

    > I tried to find a genetics chatroom but I thought maybe someone could answer me. My son who is 2
    > months old has one brown eye and one green-grey eye. It turns out my wife's aunt has the same
    > thing. Is this common? This gene would probably be recessive, so does this mean I'm also a
    > carrier? I have brown eyes and my wife has green eyes. My son's twin sister has two lighter
    > brown eyes.
    >
    > I think David Bowie has this and I heard Alexander the Great also had this. Any other
    > famous people?
    >
    > Craig

    This is usually due to mitotic recombination producing a gynadromorph. Your son inherited one brown
    eyed allele (dominant) and one blue eyed allele (recessive). Most of his cells have homologous
    chromosomes, one of which has the brown allele and the other has the blue allele. There was a mix up
    with the chromsomes sometime during the early development of the embryo when cells of the head were
    being generated. The two homologous chromosomes recombined and one daughter cell of a mitotic
    division got two chromosomes each with the recessive blue allele. Cells descended from that
    recombinant would produce blue eyes. The normal heterozygous cells would produce brown eyes. There
    is probably nothing wrong with your son. You quite often see this event in the eye itself where
    people have pie wedge cuts of different color. The pie cut is due to this event and the further cell
    divisions as the iris develops. This means that the cells of the iris start to develop near the
    pupil and more division occurs as the eye grows.

    There are rarer instances where other chromosomal abnormalities occur like translocations and
    deletions. In these cases there could be detrimental consequences where large chunks of the
    chromosome may be missing in the cells of the blue eyed kind. Essentially they are missing the brown
    allele due to partial or full chromosome loss. These are usually lethal to the cells so you do not
    often see them. I really wouldn't worry about it, but if you see signs that your son has vision
    problems I would not ignore them. You would have to get really unlucky to have something like that
    happen. The most common cause is mitotic recombination.
     
  5. Irr

    Irr Guest

    Marilyn Manson comes to mind, but I'm guessing that's not quite the same :).

    In any case, Scientific American has a short but good "Ask the Experts" response on so-called
    heterochromia iridium: picID=12 A bit more technical but referenced and linked description can be
    found on the Online Mendelian Inheritance in Man (OMIM) compendium:
    http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=142500

    Lastly the madsci.org archives have some detailed Q&A descriptions of heterochromia, the search
    engine is a good place to start (search: "heterochromia" produces several relevant threads):
    http://www.madsci.org/MS_search.html

    Hope this is helpful to you.

    "Craig Feinstein" <[email protected]> wrote in message news:[email protected]...
    > I tried to find a genetics chatroom but I thought maybe someone could answer me. My son who is 2
    > months old has one brown eye and one green-grey eye. It turns out my wife's aunt has the same
    > thing. Is this common? This gene would probably be recessive, so does this mean I'm also a
    > carrier? I have brown eyes and my wife has green eyes. My son's twin sister has two lighter
    > brown eyes.
    >
    > I think David Bowie has this and I heard Alexander the Great also had this. Any other
    > famous people?
    >
    > Craig
     
  6. On 2004-02-26, Wirt Atmar <[email protected]> wrote:
    >
    [snip]
    > The general morphological description is called "heterochromia irides", which means nothing more
    > in plain English than "differently colored irises."
    >

    In plain English, this condition is referred to (at least in horses) as "wall-eyed".

    AC

    --
    Using Linux GNU/Debian - Windows-free zone http://www.acampbell.org.uk (book reviews and articles)
    Email: replace "www." with "[email protected]"
     
  7. R.Schenck

    R.Schenck Guest

    [email protected] (Craig Feinstein) wrote in message news:<[email protected]>...
    > I tried to find a genetics chatroom but I thought maybe someone could answer me. My son who is 2
    > months old has one brown eye and one green-grey eye. It turns out my wife's aunt has the same
    > thing. Is this common? This gene would probably be recessive, so does this mean I'm also a
    > carrier? I have brown eyes and my wife has green eyes. My son's twin sister has two lighter
    > brown eyes.
    >
    > I think David Bowie has this and I heard Alexander the Great also had this. Any other
    > famous people?
    >
    > Craig

    whatsername? doctor quinn medecine woman has this too. Apprently its not uncommon.
     
  8. Ron Okimoto

    Ron Okimoto Guest

    [email protected] (Wirt Atmar) wrote in message news:<[email protected]>...
    > Craig asks:
    >
    > >I tried to find a genetics chatroom but I thought maybe someone could answer me. My son who is 2
    > >months old has one brown eye and one green-grey eye. It turns out my wife's aunt has the same
    > >thing. Is this common? This gene would probably be recessive, so does this mean I'm also a
    > >carrier? I have brown eyes and my wife has green eyes. My son's twin sister has two lighter
    > >brown eyes.
    > >
    > >I think David Bowie has this and I heard Alexander the Great also had this. Any other famous
    > >people?
    >
    > This is a recurring question here on this newsgroup. Enclosed below is how I answered the question
    > approximately four years ago:
    >
    > ======================================
    >
    > From: Wirt Atmar ([email protected]) Subject: Re: Human eye -- weird pigmentation Newsgroups:
    > sci.bio.evolution Date: 2000/01/05
    >
    > Louann Miller asks:
    >
    > >Just a quick question, probably not controversial in any way but an oddity I've been wondering
    > >about over time.
    > >
    > >I had a college classmate whose left eye was two different colors. The iris was divided into two
    > >distinct half-circle shapes, blue on one side and light brown on the other. The dividing line
    > >(vertical) was sort of greenish. Her right eye was the same shade of blue as the blue half of her
    > >left eye.
    > >
    > >She said it had always been like that, it didn't hurt, and she didn't have any vision problems. I
    > >didn't think to ask if anyone else in the family had it. It was weird enough to be memorable.
    > >I've never met or heard of anyone else with the same condition (except a fictional character in
    > >George MacDonald Frazier's "Flashman" novels, which hardly counts.)
    > >
    > >So: what is the name of this condition? Is it genetic or something in the prenatal environment?
    > >Is is related to the more common condition where a person (or a cat or dog) can have each eye a
    > >single different color? Etc. I'm interested in any information anyone has.
    >
    > The general morphological description is called "heterochromia irides", which means nothing more
    > in plain English than "differently colored irises."
    >
    > In that, the condition is not normal, and even though the bearer may be completely non-impeded by
    > its presence, it is a genetic "defect." However, it is often more serious than that. Heterochromia
    > irides, especially when it refers to eyes of two different colors -- but sometimes in eyes where
    > one iris is either splotchy with both blue and green/brown colors or evenly divided into two
    > differently colored hemispheres -- is a primary diagnostic character for Waardenburg Syndrome
    > (see: http://www.icondata.com/health/pedbase/files/WAARDENB.HTM ), a developmental abnormality
    > that is common to many large mammals, exactly as you suggest.
    >
    > Humans, cats and dogs that exhibit eye colors that are quite markedly differently colored, where
    > one eye is blue and the other green or brown, are often mildly to profoundly deaf. The abnormality
    > appears to be due to a point defect in the pax-3 gene, a homeo box gene that is widely expressed
    > during early embryogenesis, thus explaining the wide range of effects that the gene has.
    >
    > Waardenburg Syndrome is inherited dominantly, however it is suspected that only perhaps 20% of
    > those bearing some form of the defect are actually aware of it, its effects being so mild in
    > most people.
    >
    > More information can be found at:
    >
    > http://www.boystown.org/deafgene.reg/waardsx.htm
    >
    > Wirt Atmar
    >
    > ======================================
    >
    > Wirt Atmar

    There is no reason to panic. Waardenburg is not the only reason for these eye color changes. I
    worked with MITF a couple of years ago and if there were a reason to panic you would know already.
    There would be a family history of this disease unless you had one of the mild alleles. It is
    inherited as a dominant trait. Not only that, but only 2% of the cases of genetic deafness are
    Waardenburg. This is a significant portion of deaf cases, but it isn't a significant portion of the
    population.

    >From what I recall not all Waardenburg patients exhibit this
    phenotype. Certain MITF mutations have a 5 to 8 times higher rate of showing occular color changes.
    This tells me that most of the Waardenburg patients may not have the eye color change. It is
    associated with the disease. The reason for the occular color changes is just what I posted. It may
    be a dominant for clinical symptoms, but it isn't a dominant for pigmentation changes. It probably
    shows a higher than normal rate of these color changes because PAX and MITF are very important genes
    and messing them up affects a lot of genes. There are very many more somatic mutations that will
    cause a color shift for MITF than the normal blue eyed alleles found among humans. There are orders
    of magnitude more normal (nonlethal) blue eyed heterozygotes than MITF or PAX blue eyed
    heterozygotes. MITF and PAX mutations are not often found in the homozygous condition and when they
    are they exhibit extreme phenotypes as well as blue eyes.

    What seems to be happening is that one good copy of MITF is all you need to produce melanin, but in
    some of your cells mutants or recombinants happen and you get two bad copies or you lose the good
    copy. When this happens in the eye you get blue instead of brown. In the case of MITF, messing up
    some other gene like tyrosinase is known to cause the color shift. So color shifting will probably
    occur at a higher frequency than for other blue eyed alleles.

    I have never seen the number of normal people with occular color shifting compared to Waardenburg
    patients. I am sure that the frequency will be much higher in Waardenburg patients, but it will not
    be zero among normals because of the high frequency of normal (nonlethal) blue eyed alleles in the
    population. I expect the overall frequency of color shift due to normal blue eyed heterozygotes to
    be higher in the population than those due to Waardenburg because Waardenburg is such a low
    frequency in the population, but I've never seen the numbers.

    If you are worried about this. Check out an expert on Waardenburg.
     
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