The Human Genome Project is an international effort to identify human genes and find genes for various genetic diseases. There are nearly 4,000 known genetic disorders and countless diseases whose origin may be due in part to genetic malfunctions. Thus far, scientists have estimated there are 50,000 to 100,000 human genes. Scientists hope that projects such as the Human Genome Project will enable scientists, in the indeterminate future, to identify and treat all diseases to which humans are susceptible. Much attention has been focused on the so-called genetic metabolic diseases in which a defective gene causes an enzyme to be either absent or ineffective in causing a particular metabolic reaction effectively.
Gene therapy is a potential approach to the treatment of genetic disorders in human beings.
This is a technique whereby a working gene replaces the absent or faulty gene, so that the body can make the correct enzyme or protein and consequently eliminate the root cause of the disease. The American Society of Gene Therapy defines gene therapy as the treatment of disease by either replacing damaged or abnormal genes with normal ones or providing new genetic instructions to help fight disease. Gene therapy is the extension of conventional medicine to treat disease by administering genetic material rather than a drug. A multitude of ethical, legal and social issues must be addressed in gene therapy. Preliminary attempts at gene therapy are exorbitantly expensive.