Table 1.

Subsidiary categories of gene therapy.

Type of Gene Therapy	Definition	Example
Direct	The intentional modification of a specific somatic gene in order to correct defective genes or to fix an allele's malign function.	Single-base pair editing to resolve insertions or deletions that lead to defective proteins.
Compensatory	The induction of expression of genetic material that compensates for lost or aberrant cellular function.	Editing of gene to increase or decrease expression in target cell, or induce expression normally turned off.
Augmenting	The introduction of a novel function that would not otherwise be present in the target cell type.	Editing of a gene to provide a different function from what is typical; insertion of a new version of a gene into the genome (as opposed to editing the existing version)