Chromosome disorders can arise when sex cells are formed

Chromosome disorders in sex cells cause infertility, miscarriage and irregular numbers of chromosomes (aneuploidy) in neonates.

A new study from Karolinska Institutet published in the scientific journal Nature Genetics shows how chromosome disorders can arise when sex cells are formed.

Sex cells contain a control station for monitoring the mechanism that ensures that the correct numbers of chromosomes are distributed during cell division. Scientists have now shown that there is an alternative distribution mechanism in female sex cells that cause chromosome disorders. Aberrant chromosomes orientate themselves like normal chromosomes, and this ability to adopt double identities protects them from detection by the control centre.

"We believe that this new fundamental mechanism can help to explain why chromosome disorders are so common in female sex cells," says Professor Christer Hg, leader of the study.

The research might eventually lead to new medical treatments able to reduce the risk of foetal damage.

Over 0.3 per cent of children are born with some kind of chromosome disorder. Most develop Downs Syndrome, or obtain the wrong number of sex chromosomes and develop Turner's or Klinefelter's syndrome. Turner's syndrome only occurs in females and is caused when one of the two X chromosomes is missing. Girls with Turner's have arrested development and if no treatment is given do not enter puberty. Klinefelter's syndrome affects males, who receive an extra X chromosome. Symptoms include concentration difficulties, poor motor skills and infertility.

Comments

  1. Graeme Tucker Graeme Tucker New Zealand says:

    "Over 0.3 per cent of children are born with some kind of chromosome disorder."

    The numbers have actually been quantified, I am amazed.

    "Most develop Downs Syndrome"

    But Downs is not a sex chromosome disorder, so why mention it?  You don't mention Fragile X that does cause mental retardation, and this article is about sex chromosome aneuploidy.

    "or obtain the wrong number of sex chromosomes and develop Turner's or Klinefelter's syndrome."

    Whilst it is true that Turners is present at birth it is not true of Klinefelters syndrome.
    Klinefelters syndrome only develops after the onset of puberty.

    "Turner's syndrome only occurs in females"

    That is not entirely true.  There are such people as Turner Mosaic Males.   And to be realistic, the missing chromosome can be a Y.   Most people just assume the missing chromosome was another X

    "Girls with Turner's have arrested development and if no treatment is given do not enter puberty."

    They are short in stature but mentally normal.  I think "arrested development" gives the wrong impression.  

    "Klinefelter's syndrome affects males, who receive an extra X chromosome."

    Or who can have ANY degree of additional X  genetic material, even just a mere repeat sequence of and X, on their one and only X.  XY males can develop Klinefelters syndrome, and I know a man with just this karyotype so, expand your knowledge!  

    "Symptoms include concentration difficulties"

    Utter rubbish.  See males and females with Kallmann syndrome and you won't find any such thing.  Hypogonadism is what Klinefelters syndrome is, and a primary cause.  Kallmann  syndrome is a  secondary cause, and evident prenatally yet no educational difficulty or memory difficulty is found.  

    XXY and Klinefelters Syndrome are not the same things  

    "poor motor skills"

    Not related to hypogonadism'

    "infertility."

    One out of three, you can do better.

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News-Medical.Net.
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