Scientific developments in the field of genetics are being referred to as a “revolution.” One demonstration of that revolution is the recent dramatic growth in the number and availability of genetic tests. Today, more than 1,500 clinically applicable genetic tests are available. Many experts tout our developing genetic testing capability as the dawning of a new age in medicine's ability to diagnose, treat, and prevent illness, whereas others fear its abuse. This chapter discusses basic concepts in genetics, addresses more focused questions relating to genetic testing, and makes recommendations about whether genetic testing is right for you and, if so, how to proceed.

The Basics

Genetic testing has both benefits and limitations, and the decision whether to be tested is personal and complex. It is important to start with an understanding of the basics.

• Cells are basic building blocks of all living things. The human body is composed of trillions of cells, which provide structure for the body, take in nutrients and convert these to energy, carry out specialized functions, and contain the body's hereditary materials.

• DNA (deoxyribonucleic acid) residing within the nucleus of each cell constructs the blueprint for making proteins that build cells, tissues, and enzymes that trigger biochemical reactions in cells. The structure of DNA is a two-stranded, spiraled double-helix. Every cell in your body (except for mature red blood cells, which have no nucleus) contains the same DNA.

• RNA, or ribonucleic acid, receives instructions from DNA and carries them to the ribosome, the site of protein synthesis in the cell.

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