Inversion, pericentric chromosome
A basic type of chromosome rearrangement in which a segment that includes the centromere (and so is pericentric) has been snipped out of a chromosome, turned through 180 degrees (inverted), and inserted back into its original location in chromosome. The feature that makes it pericentric is that both breaks are on either side of the centromere (the point at which the chromosome attaches to the spindle).
Any chromosome inversion can be inherited and have come from one of the parents to a child. Or the inversion can appear for the first time in a child.
An inversion can be “balanced”, meaning that it has all the genes present in the normal uninverted chromosome. Or an inversion can be “unbalanced”, meaning that genes been have deleted (lost) or duplicated.
A balanced inversion in a child causes no problems. An unbalanced inversion is abnormal and is often associated with problems such as development delay (and later, mental retardation) (substitute intellectual disability anywhere that mental retardation appears in glossary) and multiple congenital anomalies (birth defects).
Inversions can also be acquired in a body cell (a somatic cell) and be a step involving that cell in a precancerous and cancerous process.
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1) To turn inward. To invert the foot is to move its forepart toward the midline of the body. 2) To turn upside down or inside out. Inversion of the nipple can be normal or be a sign of an underlying tumor. 3) To reverse in position or order. A DNA sequence may be inverted. […]
- Invest
In medicine, to envelop, cover, or embed. For example, a dentist might invest a patient’s teeth with a wax material in order to form a mold of it.
- Involuntary
Done other than in accordance with the conscious will of the individual. The opposite of voluntary. The terms “voluntary” and “involuntary” apply to the human nervous system and its control over muscles. The nervous system is divided into two parts — somatic and autonomic. The somatic nervous system operates muscles that are under voluntary control. […]
- Involute
1. Literally, to turn inward or roll inward. 2. To decrease in size after an enlargement. The uterus involutes after pregnancy. The thymus involutes after adolescence. 3. To undergo a retrograde change. After treatment, a tumor may involute. 4. To shrink physically and emotionally with advancing age. From the Latin involutio, from in- meaning into […]
- Involution
A retrograde change. After treatment, a tumor may involute; with advancing age, there may be physical and emotional involution.