Written and peer-reviewed by physicians—but use at your own risk. Read our disclaimer.

banner image

amboss

Trusted medical answers—in seconds.

Get access to 1,000+ medical articles with instant search
and clinical tools.

Try free for 5 days

Chromosomal aberrations

Last updated: November 13, 2020

Summary

Structural and numerical chromosomal aberrations may affect either the autosomes or gonosomes and are a common cause of spontaneous abortions. Autosomal aberrations that are frequently observed are trisomy 13 (Patau syndrome), trisomy 18 (Edwards syndrome), and the most common and widely recognized chromosomal aberration, trisomy 21 (Down syndrome). These conditions have an extra copy of the chromosome to which their name refer. The risk of autosomal aberrations increases with maternal age. Characteristic features include facial and skeletal malformations, which are usually recognizable at birth. The conditions are further associated with congenital heart defects and malformations of other internal organs. Turner syndrome and Klinefelter syndrome are gonosomal aberrations in which individuals have a missing X chromosome or an additional X chromosome, respectively. These conditions are primarily characterized by impaired development of secondary sexual characteristics and infertility secondary to gonadal dysgenesis. The diagnosis for all chromosomal aberrations is confirmed via karyotyping.

General information

Definitions

Epidemiology

  • Chromosomal aberrations are the most common cause of spontaneous abortions (accounting for 60% of cases).
    • Approx. 50% of anomalies are trisomies.
    • Approx. 20% of anomalies are triploidies.

Overview of viable numerical chromosomal aberrations

Trisomy 13 (Patau syndrome)

The age of Puberty onset is 13: Patau syndrome is caused by trisomy 13.

7 Ps of Patau syndrome: holoProsencephaly, cleft liP and Palate, Polydactyly, Pump disease (congenital heart disease), Polycystic kidney disease, cutis aPlasia.

References:[3][4][5]

Trisomy 18 (Edwards syndrome)

PRINCE Edward turned 18: Prominent occiput, Rocker-bottom feet, Intellectual disability, Nondisjunction (in meiosis), Clenched fists, low-set Ears, and chromosome 18.

References:[3][5]

Down syndrome (trisomy 21)

See article on “Down syndrome.

47,XYY syndrome and 47,XXX syndrome

References

  1. XYY Syndrome. https://rarediseases.org/rare-diseases/xyy-syndrome/. Updated: January 1, 2012. Accessed: March 6, 2017.
  2. Trisomy X. https://rarediseases.org/rare-diseases/trisomy-x/. Updated: January 1, 2014. Accessed: March 6, 2014.
  3. 47,XYY syndrome. https://ghr.nlm.nih.gov/condition/47xyy-syndrome#statistics. Updated: February 14, 2017. Accessed: February 16, 2017.
  4. triple X syndrome. https://ghr.nlm.nih.gov/condition/triple-x-syndrome#statistics. Updated: February 14, 2017. Accessed: February 16, 2017.
  5. Otter M, Schrander-stumpel CT, Curfs LM. Triple X syndrome: a review of the literature. Eur J Hum Genet. 2009; 18 (3): p.265-271. doi: 10.1038/ejhg.2009.109 . | Open in Read by QxMD
  6. Data & Statistics on Birth Defects. https://www.cdc.gov/ncbddd/birthdefects/data.html. Updated: January 23, 2020. Accessed: June 29, 2020.
  7. Meyer RE, Liu G, Gilboa SM, et al. Survival of children with trisomy 13 and trisomy 18: A multi-state population-based study. American Journal of Medical Genetics Part A. 2015; 170 (4): p.825-837. doi: 10.1002/ajmg.a.37495 . | Open in Read by QxMD
  8. Benacerraf BR. Sonographic Findings Associated with Fetal Aneuploidy. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/sonographic-findings-associated-with-fetal-aneuploidy.Last updated: March 27, 2017. Accessed: May 10, 2017.
  9. Weremowicz S. Congenital Cytogenetic Abnormalities. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/congenital-cytogenetic-abnormalities.Last updated: August 24, 2016. Accessed: May 10, 2017.
  10. Messerlian GM, Palomaki GE. Laboratory Issues Related to Maternal Serum Screening for Down Syndrome. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/laboratory-issues-related-to-maternal-serum-screening-for-down-syndrome.Last updated: February 4, 2016. Accessed: May 10, 2017.