Chromosomal inversion

Jump to navigation Jump to search

WikiDoc Resources for Chromosomal inversion

Articles

Most recent articles on Chromosomal inversion

Most cited articles on Chromosomal inversion

Review articles on Chromosomal inversion

Articles on Chromosomal inversion in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Chromosomal inversion

Images of Chromosomal inversion

Photos of Chromosomal inversion

Podcasts & MP3s on Chromosomal inversion

Videos on Chromosomal inversion

Evidence Based Medicine

Cochrane Collaboration on Chromosomal inversion

Bandolier on Chromosomal inversion

TRIP on Chromosomal inversion

Clinical Trials

Ongoing Trials on Chromosomal inversion at Clinical Trials.gov

Trial results on Chromosomal inversion

Clinical Trials on Chromosomal inversion at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Chromosomal inversion

NICE Guidance on Chromosomal inversion

NHS PRODIGY Guidance

FDA on Chromosomal inversion

CDC on Chromosomal inversion

Books

Books on Chromosomal inversion

News

Chromosomal inversion in the news

Be alerted to news on Chromosomal inversion

News trends on Chromosomal inversion

Commentary

Blogs on Chromosomal inversion

Definitions

Definitions of Chromosomal inversion

Patient Resources / Community

Patient resources on Chromosomal inversion

Discussion groups on Chromosomal inversion

Patient Handouts on Chromosomal inversion

Directions to Hospitals Treating Chromosomal inversion

Risk calculators and risk factors for Chromosomal inversion

Healthcare Provider Resources

Symptoms of Chromosomal inversion

Causes & Risk Factors for Chromosomal inversion

Diagnostic studies for Chromosomal inversion

Treatment of Chromosomal inversion

Continuing Medical Education (CME)

CME Programs on Chromosomal inversion

International

Chromosomal inversion en Espanol

Chromosomal inversion en Francais

Business

Chromosomal inversion in the Marketplace

Patents on Chromosomal inversion

Experimental / Informatics

List of terms related to Chromosomal inversion


A clay model showing why heterozygous inversion loops are visible in polytene chromosome preparations
An inversion loop in the A arm of a chromosome from an Axarus species midge

An inversion is a chromosome rearrangement in which a segment of a chromosome is reversed end to end. An inversion occurs when a single chromosome undergoes breakage and rearrangement within itself. Inversions are of two types: paracentric and pericentric.

Paracentric inversions do not include the centromere and both breaks occur in one arm of the chromosome. Pericentric inversions include the centromere and there is a break point in each arm.

Cytogenetic techniques may be able to detect inversions, or inversions may be inferred from genetic analysis. Nevertheless, in most species small inversions go undetected. In insects with polytene chromosomes, for example Drosophila, preparations of larval salivary gland chromosomes allow inversions to be seen when they are heterozygous. This useful characteristic of polytene chromosomes was first advertised by Theophilus Shickel Painter in 1933.[1]

Inversions usually do not cause any abnormalities in carriers as long as the rearrangement is balanced with no extra or missing genetic information. However, in individuals which are heterozygous for an inversion, there is an increased production of abnormal chromatids (this occurs when crossing-over occurs within the span of the inversion). This leads to lowered fertility.

Families that may be carriers of inversions may be offered genetic counseling and genetic testing. [2]

The most common inversion seen in humans is on chromosome 9, at inv(9)(p11q12). This inversion is generally considered to have no deleterious or harmful effects, but there is some evidence it leads to an increased risk for miscarriage for about 30% of affected couples.

References

  1. Painter T.S. 1933. A new method for the study of chromosome rearrangements and the plotting of chromosome maps. Science 78, 585-6.
  2. Gardner R.J.M. and Sutherland G.R. 2004. Chromosome abnormalities and genetic counselling. Oxford.

See also


de:Inversion (Genetik) it:Inversione (cromosoma) nl:Inversie (chromosomen)

Template:WH Template:WS