key concept 15.5 Genetic Diseases Can Be Treated

Most treatments for genetic diseases simply try to alleviate the patient’s symptoms. But to effectively treat these diseases—whether they affect all cells, as in inherited disorders such as PKU, or only somatic cells, as in cancer—physicians must be able to diagnose the disease accurately, understand how the disease works at the molecular level, and intervene early, before the disease ravages or kills the individual. There are two main approaches to treating genetic diseases:

  1. Modifying the disease phenotype

  2. Replacing the defective gene (modifying the genotype)

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  • Some genetic diseases are treated at the phenotype level.

  • Other genetic diseases can be treated at the level of the gene using gene therapy.