gemfibrozilA drug that lowers the
level of fats in the blood. Gemfibrozil is
usually given to people with hyper-
lipidaemia after dietary measures have
failed to reduce blood fat. Gemfibrozil
may cause nausea and diarrhoea, and
should not be taken by people with
kidney or liver disease.
gender identityThe inner feeling of
maleness or femaleness. Gender identity
is not necessarily the same as biologi-
cal sex. It is fixed within the first 2–3
years of life and is reinforced during
puberty; once established, it cannot
usually be changed. Gender identity prob-
lems, such as transsexualism, occur when
a person has persistent feelings of dis-
comfort about his or her sexual identity.
geneA unit of the material of heredity.
A gene corresponds to a particular area
of DNAwithin a chromosome. There are
about 30,000 different genes arranged
on the 23 pairs of chromosomes. These
genes control the development and
functioning of organs and body systems,
providing an “instruction manual” for an
individual’s growth, survival, reproduc-
tion, and possibly also for aging and
death. Genes also play a part, together
with environmental factors, in determin-
ing a person’s intelligence, personality,
and behaviour.
Genes fulfil these functions by direct-
ing the manufacture of proteins. Many
proteins have a structural or catalytic
role in the body. Others switch genes
“on” or “off”. The genes that make these
regulatory proteins are called control
genes. The activities of control genes
determine the specialization of cells;
within any cell some genes are active
and others idle, according to its particular
function. If the control genes are disrupt-
ed, cells lose their specialist abilities
and multiply out of control; this is the
probable mechanism by which cancers
form (see carcinogenesis; oncogenes).
Each of a person’s body cells contains
an identical set of genes because all the
cells are derived, by a process of division,
from a single fertilized egg, and with
each division the genes are copied to
each offspring cell (see mitosis; meiosis).
Occasionally, a fault occurs in the copy-
ing process, leading to a mutation.The
gene at any particular location on a
chromosome can exist in any of various
forms, called alleles. If the effects of an
allele mask those of the allele at the
same location on its partner chromo-
some, it is called dominant. The masked
allele is recessive. (See also genetic
code; inheritance.)
generalized anxiety disorderA psy-
chiatricillness characterized by chronic
and persistent apprehension and ten-
sion that has no particular focus. There
may also be physical symptoms such as
trembling, sweating, lightheadedness,
and irritability. The condition can be
treated with psychotherapy or with
drugs such as beta blockers, sedatives or
tranquillizersthat relieve symptoms but
do not treat the underlying condition.
(See anxiety; anxiety disorders.)
general paralysis of the insaneAn
outdated term used to describe the
stage of mental and physical deterior-
ation that occurs in untreated or
unsuccessfully treated syphilis.
general practiceThe term used in the
UK to describe the provision of personal
medical care outside a hospital setting.
The term is now more commonly known
as primary care.
generic drugA medicinal drug marketed
under its official medical name (its
generic name) rather than under a
patented brand name.
gene therapy A technique used for the
treatment of certain genetic disorders,
such as cystic fibrosis, and certain types
of cancer. In gene therapy, copies of a
normal geneare inserted, using genetic
engineeringtechniques, into the DNA
of cells to counter the effects of a faulty
gene or to produce substances that
help fight cancer.
genetic codeThe inherited instructions,
contained in genes, that specify the
activities of cells and thereby the de-
velopment and functioning of the whole
body. Each gene in a chromosomecon-
tains the coded instructionsfor a cell to
make a particular protein, which may
have a specific structuralor catalytic
function in the body.
The DNA that makes up genes con-
sists of 2 long intertwined strands, each
consisting of a sequence of 4 differentGEMFIBROZIL GENETIC CODE
G