tetrasomy
{{other uses|Tetrasomy (disambiguation)}}
{{Infobox medical condition (new)
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A tetrasomy is a form of aneuploidy with the presence of four copies, instead of the normal two, of a particular chromosome.
Causes
=Full=
Full tetrasomy of an individual occurs due to non-disjunction when the cells are dividing (meiosis I or II) to form egg and sperm cells (gametogenesis). This can result in extra chromosomes in a sperm or egg cell. After fertilization, the resulting fetus has 48 chromosomes instead of the typical 46.
=Autosomal tetrasomies=
- Cat eye syndrome where partial tetrasomy of chromosome 22 is present
- Pallister-Killian syndrome (tetrasomy 12p)
- Tetrasomy 9p
- Tetrasomy 18p
- Tetrasomy 21, a rare form of Down syndrome
=Sex-chromosome tetrasomies=
External links
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| ICD10 = {{ICD10|Q|97||q|97}} - {{ICD10|Q|98||q|98}}
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| MeshID = D000782
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{{Chromosomal abnormalities}}