La diferencia en una frase
Gene therapy adds a working copy of a gene and leaves the faulty one alone. CRISPR gene editing changes the DNA that is already in the cell. Both are usually given once, both are permanent for the cells they reach, and both are routinely called 'gene therapy' in ordinary conversation — but they are different interventions with different risks.
| Aspecto | Gene therapy (gene addition) | CRISPR gene editing |
|---|---|---|
| What it does | Delivers a working copy of a gene | Changes the DNA sequence already present |
| The faulty gene | Left in place, still faulty | Disabled, corrected or removed |
| Where the new DNA goes | Wherever the vector puts it, or as a separate episome | Nowhere — the existing sequence is altered |
| Best suited to | A missing or non-functional protein | A harmful protein, or the wrong amount of a normal one |
| Durability | Can fade as cells divide, with non-integrating vectors | Inherited by every daughter cell |
| Main risks | Vector immunity, liver toxicity at high doses, insertional mutagenesis with integrating vectors | Off-target edits, chromosomal rearrangements at cut sites |
| Approved products | Several | One |
| Example | Zynteglo, Luxturna | Casgevy |
Why the confusion persists
Both are regulated under the same category, both are administered once, both cost millions, and both are described in press coverage as 'gene therapy'. The FDA approved Casgevy (editing) and Lyfgenia (addition) for the same disease on the same day, which made the conflation almost inevitable — and also created the clearest available side-by-side comparison.
Sources
- U.S. Food and Drug Administration
Approved cellular and gene therapy products ↗