Supriya Ghosh (Editor)

Tetrasomy

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Specialty
  
medical genetics

MeSH
  
D000782

ICD-10
  
Q97 - Q98

Orphanet
  
3305

A tetrasomy is a form of aneuploidy with the presence of four copies, instead of the normal two, of a particular chromosome.

Contents

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 tetrasomy of chromosome 22 is present
  • Pallister-Killian syndrome (tetrasomy 12p)
  • Tetrasomy 9p
  • Tetrasomy 18p

    • Sex-chromosome tetrasomies

  • 48, XXXX syndrome
  • 48, XXYY syndrome
  • Klinefelter's syndrome, where XXXY tetrasomy is present

    • References

    Tetrasomy Wikipedia
    (Text) CC BY-SA