Webster's New World Medical Dictionary

chromosome inversion, pericentric
A basic
type of chromosome rearrangement in which a seg-
ment that includes the centromere (and is therefore
pericentric) is snipped out of a chromosome,
inverted, and inserted back into the chromosome.
The feature that makes it pericentric is that the
breaks are on both sides of the centromere.
chromosome map
The chart of the linear array
of genes on a chromosome. The Human Genome
Project contributes to the mapping of the human
chromosomes. See also 
Human Genome Project.
chromosomes in multiple miscarriages
Chromosome abnormalities (such as deletions,
additions, or translocations) that are responsible
for causing miscarriages. A couple that has had
more than one miscarriage has about a 5 percent
chance that one member of the couple is carrying
an irregular chromosome that is responsible for the
miscarriages.
chronic
In medicine, lasting a long time. A
chronic condition is one that lasts 3 months or
more. Chronic diseases are in contrast to those that
are acute (abrupt, sharp, and brief) or subacute
(within the interval between acute and chronic).
chronic arthritis, systemic-onset juvenile
See 
Still’s disease.
chronic bronchitis
See 
bronchitis, chronic.
chronic disease
A disease that persists for a long
time, typically 3 months or more. Examples of
chronic diseases include arthritis, diabetes, and
emphysema. In comparison, an acute illness is of
short duration. See also 
acute.
chronic fatigue syndrome
A debilitating and
complex disorder characterized by profound fatigue
that lasts 6 months or longer, is not improved by
bed rest, and may be worsened by physical or men-
tal activity. Abbreviated CFS. Persons with CFS most
often function at a substantially lower level of activ-
ity than they were capable of before the onset of the
illness. In addition to these key defining character-
istics, patients report various nonspecific symp-
toms, including weakness, muscle pain, impaired
memory and/or mental concentration, insomnia,
and postexertional fatigue lasting more than 24
hours. In some cases, CFS can persist for years. The
cause or causes of CFS have not been identified, and
no specific diagnostic tests are available. Moreover,
because many illnesses have incapacitating fatigue
as a symptom, care must be taken to exclude other
known and often treatable conditions before a diag-
nosis of CFS is made. Also known as chronic fatigue
and immune dysfunction syndrome (CFIDS) and
myalgic encephalomyelitis (ME).