From Wikipedia,
the free encyclopedia
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.
Special
cytogenetics techniques are
often needed to detect inversions.
Image:Inversions.jpg
Inversions usually do not cause
any abnormalities in carriers as
long as the rearrangment is
balanced with no extra or missing
genetic information. However,
there is an increased chance for
the production of unbalanced
chromosome rearrangements in the
offspring of carriers. Families
that may be carriers of inversions
may be offered
genetic counseling and
genetic testing.
The most common inversion seen
in humans is on chromosome 9, at
inv(9)(p11q12). This inversion has
no deleterious or harmful effects
and does not appear to lead to an
increased risk for miscarriage or
abnormalities in offspring.
