Gene therapy works by injecting healthy genes into cells to correct malfunctioning ones or replace disease-causing ones; however, its introduction may trigger immune rejection of new DNA strands introduced into cells.
To circumvent this obstacle, doctors inject genes directly into cells using vectors – most notably viruses like AAV and LIVs.
Cost-effective DNA sequencing
DNA sequencing technology that enables scientists to gain access inside cells has become more affordable in recent years. New single molecule technologies enable much longer sequences than earlier sequencing machines could offer; some can deliver as many as 10K reads per run – enough for scientists to detect gene rearrangements associated with colon cancer or determine an individual’s methylation status.
Researchers can now explore more complex questions and address larger challenges, like discovering genetic factors underlying common diseases or interpreting genome-wide association studies (GWAS). Unfortunately, this requires more time-consuming sampling methods like collecting blood from family members or procuring cancer patient tissues as samples.
Additionally, sequencing costs have not declined at the same rate as genomic variant interpretation costs, prompting some sequencing programs to proactively query more genes than would normally have been needed in search of secondary findings; although this might increase overall costs slightly; such costs likely pale in comparison to any medical procedures that arise as a result of sequencing findings.
Improved genetic testing
Scientists have made great advances in understanding which genes contribute to various medical conditions, leading them to create genetic tests to detect them. These tests may examine just one or many genes at the same time; others are complex enough that they provide data about potential “variants of uncertain significance,” which refers to changes in your genes that don’t currently have an impact on health but could contribute to future disease risk.
Technology now exists that can detect numerous inherited diseases in people without symptoms, as well as screen pregnant women for some that may have been passed along from parent to fetus.
Provide objective, timely and credible information regarding the benefits and harms of genetic testing is a daunting challenge. While the Task Force’s recommendations do not directly address this problem, they outline overarching principles which should be used as guides when making these decisions.
Gene-based diagnosis and treatment
Researchers have spent decades developing gene-based therapies as treatments for disease. These can include replacing disease-causing genes with healthy ones or silencing those that promote disease; or altering how a gene functions altogether.
Traditional gene therapy relies on viruses to transfer healthy genes directly into cells. But scientists have developed other means of getting these beneficial genes into cells without viruses – including using modified bacteria that don’t cause infectious disease as carriers for gene delivery; or directly using RNA which doesn’t need an intermediary carrier and can be given directly into cells.
These technologies could complement or replace current genetic tests used in clinical laboratories. Up until recently, genome sequencing cost had limited its availability but has dramatically dropped in recent years, opening access to DNA testing for rare disorders as well as uncovering complex disease traits through sequencing analysis.
The future
Imagine a world in which genetic disorders could be remedied by targeting their root causes directly. That is the promise – and present reality – of gene therapy, which involves adding or replacing genes within cells to treat disease.
As one example, gene editing (also known as CRISPR-Cas9) offers one potential solution to correcting cystic fibrosis genes by replacing them with normal ones; similarly, modified adeno-associated virus therapy delivering replacement genes has recently been approved to treat haemophilia, an inherited blood disorder which prevents cells from producing enough essential clotting proteins for healthy clotting processes.
Gene therapy has also recently made strides toward treating retinal diseases like macular degeneration and retinitis pigmentosa. Doctors use a virus to deliver healthy copies of genes directly into cells of the eye that are immune-privileged, thus shielding it from damaging local immune and inflammatory reactions.
