Physicians
Dramatic advances in human genetics have recently provided powerful
tools for identifying the specific genes that cause susceptibility to
psychiatric illness. Genes explain 50-70 percent of the cause of most
psychiatric disorders. Environmental factors explain the rest. Disease
may result from the interaction of genes and environment as shown below.
In addition, mutations in different genes in different physiological
pathways may lead to susceptibility to illness. Dysfunction in one or
more distinct biological pathways may underlie illness that behaviorally
appears the same. For example, several different biological abnormalities
may each lead to mania. These different pathways then interact with environmental
factors or stresses to produce illness. However, each different pathophysiological
abnormality represents a biologically distinct disease. These diseases
differ in etiology and differ in prognosis and treatment response. These
are the diseases that will form the basis of a new biology- and etiology-based
diagnostic system.
The task of identifying all the genes involved is
large as there are likely dozens. Science is presently just at the
beginning of this process of discovery. However, already several genes
have been discovered for bipolar disorder and schizophrenia. Psynomics’ vision
is to bring these discoveries to the clinic to aid the physician in
the process of diagnosis and treatment.
Pharmacogenetics is a related and rapidly advancing field. Pharmacogenetics
refers to the study of genes that influence response to medications. It
is a common clinical experience that patients with very similar clinical
presentations may have very different responses to medications. It is likely
that much of this variation in response is genetically based. The figure
below illustrates some of the possible relationships of these genes. Disease
resulting from different susceptibility genes may manifest different response
to medications. The different biologies involved may be affected by some
drugs and not others. Alternatively, other genetic variation in pharmacodynamic
genes may influence drug response but not susceptibility to illness. Variation
in genes influencing bioavailability may also influence drug response.
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