Tetrasomy
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A Tetrasomy is a kind of aneuploidy that implicates an extra chromosome pair as a result of the presence of four copies of a specific chromosome, in an otherwise diploid cell. (Tetrasomic Chromosome Formula 2N + 2) [1][2].
Tetrasomy occurs due to nondisjunction in meiosis when both parents produce a gamete each that presents two copies of an individual chromosome, while all other chromosomes in the set present only one copy. The result is a fetus that contains 48 chromosomes, instead of the common 46 chromosomes [3].
Examples of tetrasomies abnormalities for autosomes and for sex chromosomes found in humans:
Sex-chromosome tetrasomies: [4]
- 48, XXYY and 48, XXXY: variations of the Klinefelter syndrome (occur in 1 in 18,000–50,000 male births) [5].
- 48, XXXX syndrome
Autosomal tetrasomies[6]
- Cat eye syndrome
- Pallister-Killian syndrome (tetrasomy 12p)
- Tetrasomy 18p
- Tetrasomy 9p
References
- ↑ http://ghr.nlm.nih.gov/glossary=tetrasomy
- ↑ Genetics, Rusell (Fifth Edition), Peter J. Rusell). P (207-209)
- ↑ Genetics, Rusell (Fifth Edition), Peter J. Rusell). P (207-209)
- ↑ https://en.wikipedia.org/wiki/Tetrasomy
- ↑ https://en.wikipedia.org/wiki/Klinefelter_syndrome
- ↑ https://en.wikipedia.org/wiki/Tetrasomy