Which approach might be considered a challenge for gene therapy?

The potential for unintended effects on other genes is a significant challenge for gene therapy. This issue, often referred to as "off-target effects," occurs when the gene editing tools, such as CRISPR-Cas9, intended to correct a specific genetic defect inadvertently modify other parts of the genome. These unintended modifications can lead to a variety of issues, including the potential to disrupt normal gene function, which could cause new health problems or exacerbate existing conditions.

In gene therapy, where precise manipulation of genetic material is crucial for successful treatment, the risk of influencing other genes poses a major hurdle. Ensuring the specificity and accuracy of the gene-editing process is paramount to avoid adverse effects and to achieve the desired therapeutic outcomes.

Other factors like the ease of obtaining human tissue samples, the ability to replace all damaged cells, and the high cost of therapeutic enzymes, while they can present challenges in different contexts, do not directly pertain to the core issue of gene modification accuracy and safety that is essential in gene therapy.