K.K. Jain, Textbook of Personalized Medicine, DOI 10.1007/978-1-4939-2553-7_16, 529
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Chapter 16
Personalized Management of Genetic
Disorders
Introduction
Classical genetics has blended with molecular biology to produce the revolutionary
new fi eld called molecular genetics. A large number of diseases have a genetic com-
ponent: they are either called genetic disorders (single gene defect) or have a genetic
predisposition as a part of multifactorial etiology. Role of genetics in the develop-
ment of personalized medicine has been discussed in Chap. 1. Molecular diagnostic
technologies provide the possibility of preimplantation diagnosis and prevention of
birth of affected offspring. Those missed at this stage could be detected in prenatal
diagnosis giving the parents an option in decision making for continuation of the
pregnancy. Specifi c treatments for correction of effects of genetic defects are avail-
able for some diseases and gene therapy is being developed for single gene disor-
ders. Some of the genetic disorders are described in other chapters dealing with
various systems such as the nervous system.
Molecular Diagnosis of Genetic Disorders
Currently, there are >2,500 genetic tests to detect the risk of disease but the number
is much smaller for approved and marketed tests. Several are used in clinical
research, many more are in various stages of development, and some are expected
to be available in the near future. The term diagnosis should be distinguished from
screening, which is integral to all medical evaluations. Conventional genetic screen-
ing has severe limitations. Clinical features can be ambiguous and may take years
to evolve. The biochemical tests are expensive and often give equivocal results.