Clinical sequencing analyzes a person’s genetic material, such as DNA or RNA, to obtain information relevant to their medical care. This technology offers insights that guide diagnosis and treatment decisions. It represents a significant shift in how healthcare providers address individual patient needs.
Understanding Clinical Sequencing
Clinical sequencing involves “reading” the sequence of genetic material. This process deciphers the specific order of nucleotides in DNA or RNA, which carry instructions for building and operating the human body. By examining these sequences, healthcare professionals identify variations, mutations, or gene expression patterns linked to various health conditions.
This approach differs from traditional genetic tests, which typically focus on a single gene or a small set of genes. Clinical sequencing, particularly whole exome sequencing (WES) or whole genome sequencing (WGS), examines a much broader range of genetic information, including the approximately 1% of the genome that codes for proteins (exons) or even the entire genome. This comprehensive view helps uncover genetic changes that might otherwise be missed, providing a more complete picture of an individual’s genetic makeup.
Applications in Patient Care
Clinical sequencing offers several benefits for patient care, transforming how various diseases are diagnosed and managed. It provides detailed genetic insights that can lead to personalized and effective medical interventions.
One major application is diagnosing rare and undiagnosed diseases. For individuals with perplexing symptoms that have eluded diagnosis through conventional methods, sequencing can help identify the underlying genetic causes. This can lead to a definitive diagnosis, enabling appropriate management or treatment plans.
Clinical sequencing also guides cancer treatment, an area known as precision oncology. By sequencing tumor DNA, clinicians can identify specific genetic mutations or alterations in cancer cells. This information helps select targeted therapies designed to attack these genetic weaknesses, leading to more effective and less toxic treatments.
Another application is pharmacogenomics, which focuses on how an individual’s genetic makeup influences their response to medications. Sequencing can predict whether a patient will respond well to a particular drug, experience adverse side effects, or require a modified dosage. This allows providers to tailor drug choices and dosages, optimizing treatment efficacy and minimizing risks.
The technology also extends to reproductive health, used for carrier screening and prenatal diagnosis. Carrier screening identifies individuals who carry a gene for a specific genetic condition, even without symptoms, which can inform family planning. Prenatal diagnosis involves sequencing fetal DNA to detect genetic conditions before birth, providing families with important information for pregnancy management.
The Process and Interpreting Results
Clinical sequencing typically begins with sample collection from the patient. Common sample types include blood, saliva, or tissue biopsies, depending on the specific condition being investigated. For instance, tumor samples are often used for solid cancers, while blood samples are frequently used for rare diseases.
After collection, the sample is sent to a specialized laboratory for analysis. The genetic material is extracted and prepared for sequencing. This preparation involves fragmenting the DNA into smaller pieces and adding molecular tags before loading them into a sequencing machine. The machine then “reads” the order of the chemical bases in each fragment, generating vast amounts of raw data.
Interpreting this extensive genetic data is a complex process requiring specialized expertise. Bioinformaticians use sophisticated software to align sequenced fragments to a reference human genome, identify variations, and predict their functional effects. Geneticists then clinically interpret these variants to determine their significance in relation to the patient’s condition. This often involves cross-referencing findings with established medical literature and databases.
Genetic counselors help patients understand their sequencing results. They explain complex genetic information in an accessible way, discuss the implications for the patient’s health and family, and outline available options for medical management or further testing. This guidance ensures patients can make informed decisions based on their genetic insights.
Distinguishing Clinical from Research Sequencing
It is important to understand the distinctions between clinical and research sequencing, as they serve different purposes and operate under different frameworks. Both involve analyzing genetic material, but their objectives, regulatory environments, and reporting practices vary significantly.
The primary purpose of clinical sequencing is direct patient care. It is performed to diagnose an inherited disorder, guide treatment decisions, or provide actionable information for a patient’s medical management. In contrast, research sequencing aims to advance scientific discovery, explore how genes function, develop new tests, and deepen the understanding of genetic conditions at a population level.
Clinical sequencing adheres to strict regulatory standards to ensure accuracy, reliability, and patient privacy. Clinical laboratories performing these tests must comply with regulations that dictate specific quality control and assurance measures. Research sequencing, while still following ethical guidelines, may not be subject to the same rigorous clinical laboratory oversight.
Another difference lies in reporting results. Clinical sequencing results are actionable and reported back to the patient and their healthcare provider, influencing immediate medical decisions. Conversely, findings from research sequencing studies are typically not immediately relevant to individual patient care and are often not reported back to participants.