A boy with Klinefelter syndrome (47,XXY) is born to a mother who ...

Question

A boy with Klinefelter syndrome (47,XXY) is born to a mother who is phenotypically normal and a father who has the X-linked skin condition called anhidrotic ectodermal dysplasia. The mother's skin is completely normal with no signs of the skin abnormality. In contrast, her son has patches of normal skin and patches of abnormal skin.

Which parent contributed the abnormal gamete?

Accepted Answer

Hi everyone, welcome back, let's look at the next question. It says clean filter syndrome is a condition in which an individual has an extra X chromosome, which of the following factors can cause Klinefelter syndrome. And so we recall that Klinefelter syndrome affects males. The person with client Felder syndrome has the genotype X. X. Y. And because the Y chromosome is the sex determining chromosome in humans, a person with Klinefelter syndrome is a typically male despite having two X chromosomes because they do have that Y chromosome with its S. R. Y. Gene that determines that male sex. So our question says which the following factors can cause Klinefelter syndrome? Notice that option D. Is all options are correct. So that is an option for us. So let's look at choice A. It says the male gamete carries an extra X chromosome. Well, this is correct in being a cause of Klinefelter syndrome. If there's an error in cell division in the formation the male gametes in the father of the individual client filters, we know that normally when those sperm are formed, they have either an X. Or a Y chromosome in them. So we'll draw normal sperm which combined with those egg cells of the female with an X chromosome. If there's an error in that cell division and it results in an uneven distribution. So you have some sperm that get no sex chromosomes and then you might have a sperm that gets bigger and X along with a Y inside it. When that combines with an egg, you end up with this genotype in the resulting embryo. So the male gamete having an extra X chromosome is indeed a possible cause of Klinefelter syndrome. Choice B says they're usually born to mothers of advanced maternal age. This also can be a cause of client filter syndrome. So we'll note that there just as you can have those errors in cell division in the mail formation, the male gametes. The same thing can happen in the formation of the egg cells and you might end up with an egg cell with two X chromosomes rather than just one. And these sorts of errors are more likely to occur with advanced maternal age. So a mother of advanced maternal age is more likely to have a child with Klinefelter syndrome, but we already have more than one correct answer. If I were on a test, I'd go ahead and select choice D. All options are correct, but to be thorough. Well look here at choice, C choice E says, cells divide incorrectly during fetal development and this can be at the third cause of Klinefelter syndrome. Um This results in mosaic climb filter syndrome because it means rather than the error and division occurring in the formation of the gamut, which would result in every cell in the individual's body having that extra X chromosome. If there's an error and division in the early fetal development, it occurs in just one cell, one somatic cell as that cell divides, it ends up getting an extra X chromosome due to a division error. Then all the the daughter cells, all the descendant cells that come from that particular cell have the extra X chromosome. But all cells descended from the other cells in the early embryo that did not have that error are normal. So in this case you have mosaic Klinefelter syndrome because it only affects a portion of the cells of the body. So that's usually a less severe effect on the individual than when the error occurred in the gametes. So again, which of the following factors can cause client filter syndrome. Um Choice D All options are correct. The male gamete can have an extra chromosome mothers of advanced maternal age, since that might cause errors to cause the egg cell to have an extra X. Chromosome or cells dividing incorrectly during fetal development. See you in the next video.

Key Concepts

Klinefelter Syndrome

X-linked Inheritance

Gametogenesis and Genetic Contribution

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