Homosaurus Vocabulary Site

Mosaicism involving "sex" chromosomes (https://en.homosaurus.org/v3/homoit0001020)

homoit0001020

Mosaicism involving "sex" chromosomes

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People with mosaic chromosomes have different chromosome patterns in some cells of their body than in others. Mosaicism results from random differences in how cells divide while an embryo is growing, resulting in different numbers of chromosomes in different cells (such as 45X/46XX or 45X/46XY, which are both variants of Turner syndrome, or 46XY/47XXY or 46XX/47XXY, which are both variants of Klinefelter syndrome). If someone specifically has 46XX chromosomes in some cells and 46XY in others, their variation is probably chimerism instead of mosaicism. Having mosaic chromosomes can cause someone to develop variations in their genitals, gonads, or hormone function. For example, if they have at least one Y chromosome, they may have both ovarian and testicular tissue, or genital differences like hypospadias, or they may develop some secondary sex characteristics at puberty that are not expected for the sex they were assigned. People who have mosaicism without a Y chromosome (e.g., 45X/46XX, or 46XX/47XXX) may have streak gonads or ovaries that stop functioning at an earlier age than typical, which can affect development during puberty and fertility. Other people may not have any noticeable signs of their mosaicism at all.

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History Note

Term updated in collaboration with interACT: Advocates for Intersex Youth, 2022-2023.

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Contributors

Revised during an extended collaboration with interACT: Advocates for Intersex Youth, 2022-2023.

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Issued (Created)

2019-05-14 07:04:13 UTC

Modified

2025-02-23 07:10:24 UTC

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