Whole Exome Sequencing | My Genetic DNA Center

Introduction to Whole Exome Sequencing (WES):

Whole exome sequencing (WES) is utilized when medical and family histories indicate a potential genetic origin for the observed signs and symptoms. It is often performed after previous genetic tests have failed to identify the underlying genetic cause of the patient’s condition.

What Is Whole Exome Sequencing?

Whole Exome Sequencing (WES), it is a genetic testing method that focuses on analyzing all the protein-coding regions of the genome, known as exons. These regions contain the majority of clinically significant genetic variations that can be linked to inherited disorders, rare diseases, and complex medical conditions. At My Genetic DNA Center, we use advanced sequencing technology and stringent quality standards to perform WES tests, ensuring highly accurate and reliable results. Our team of experts interprets the findings to provide actionable insights, helping patients and healthcare providers make informed decisions regarding diagnosis, treatment, and personalized healthcare planning.

It is a molecular diagnostic technique that specifically sequences all the protein-coding regions (exons) of the genome. Although the exome comprises only 1–2% of the entire human genome, it nonetheless carries approximately 85% of all known disease-related mutations. Therefore, it serves as an especially valuable and efficient target for genetic analysis in clinical diagnostics. WES selectively sequences these regions to uncover alterations (mutations) that may be responsible for a patient’s medical condition.

Why Focus on the Exome in WES?

The exome consists of all protein-coding regions of the genome, which make up about 1–2% of the total DNA but contain approximately 85% of disease-causing genetic variations. By focusing on the exome, Whole Exome Sequencing (WES) efficiently identifies clinically significant mutations without sequencing the entire genome, saving time and resources.

At My Genetic DNA Center, we use advanced WES technology to target these regions, ensuring accurate detection of genetic variations that are most relevant for diagnosing inherited disorders, rare diseases, and complex medical conditions. This targeted approach provides precise, actionable insights while maintaining efficiency and reliability.

How Does Whole exome sequencing Work?

Step by Step process of WES test is,

Sample Collection : The healthcare provider collects a small sample of blood or saliva from the patient.
DNA Extraction : The laboratory extracts genetic material (DNA) from the sample.
Sequencing : Using high-throughput next-generation sequencing (NGS), the lab sequences the exonic regions of the genome.
Bioinformatics Analysis : Experts analyze the sequence data and compare it with reference genomes to detect genomic variants, mutations, or pathogenic alterations.
Clinical Interpretation : Genetic specialists analyze the findings and match them with the patient’s symptoms to determine whether the genetic variants cause the medical condition.

Types of Variants Detected by Whole exome sequencing

WES can detect various types of genetic alterations, including:

Missense and nonsense mutations
Frameshift insertions and deletions
Splice site alterations

When Is Whole exome sequencing Recommended?

At My Genetic DNA Center, the doctors recommend WES when:

A patient presents with unexplained developmental delays, neurological symptoms, or congenital anomalies.
Previous tests failed to provide a diagnosis.
The patient’s family history shows signs of suspected inherited disorders.
The symptoms are complex, overlapping, or suggest a rare genetic condition.

Benefits of Whole Exome Sequencing:

Focused and High-Yield :

By targeting the exome, WES avoids scanning non-coding regions and focuses on the sections most likely to contain clinically relevant mutations.

Faster Diagnosis :

WES can help shorten the diagnostic odyssey by identifying the cause of a condition more efficiently than traditional single-gene or panel tests.

Supports Precision Medicine :

WES provides valuable insights that help physicians create personalized treatment plans tailored to the patient’s unique genetic profile.

Family Planning and Risk Assessment :

Results from WES can help families understand inheritance patterns and make informed decisions about future pregnancies or testing for other relatives.

Limitations of Whole Exome Sequencing:

It may miss mutations in non-coding regions, introns, or regulatory elements.
Structural variants and large deletions may be difficult to detect.
Some detected variants may be of uncertain clinical significance (VUS).
Genetic specialists may reveal incidental or secondary findings that do not relate to the original reason for testing, which raises both ethical and emotional considerations for patients and providers.

Whole Exome Sequencing vs. Whole Genome Sequencing:

Although Whole Exome Sequencing (WES) primarily focuses on protein-coding regions, by comparison, Whole Genome Sequencing (WGS) analyzes the entire genome, including introns, regulatory sequences, and non-coding DNA. Furthermore, WGS delivers a more comprehensive view of genetic information. Nevertheless, it tends to be more costly and time-consuming. Consequently, healthcare professionals must carefully consider the advantages and drawbacks of each method in relation to the patient’s specific clinical requirements.

Exome sequencing focuses solely on the coding regions of genes—areas that directly influence protein production. While it effectively identifies variants within these exons, it does not capture changes in non-coding or structural regions of the genome, which may also contribute to disease. These broader types of variants are detectable through Whole-Genome Sequencing (WGS). Since exons represent just about 1% of the entire human genome, exome sequencing does not cover the remaining 99%.

What is the Difference between Exome and Genome?

DNA serves as a unique blueprint for an individual’s existence. The genome encompasses the entirety of a person’s DNA, encompassing both the introns and exons. On the other hand, the exome solely comprises the exons, which are the specific regions utilized in protein synthesis. The introns and other non-coding DNA sequences are not considered part of the exome.

What is the method used to perform the test?

The method that is used to perform the WES test is Next-generation sequencing (NGS). This advanced technology actively determines the order of nucleotides in entire genomes or targeted regions of DNA or RNA.

Applications of Whole Exome Sequencing (WES):

Diagnosis of Genetic Disorders: Whole Exome Sequencing is an effective tool for identifying the genetic basis of diseases with multiple possible genetic causes, especially when traditional methods fail to pinpoint a diagnosis.
Prenatal Genetic Screening: It helps detect genetic abnormalities in a fetus that may result in developmental issues or congenital conditions, allowing early assessment of inheritance patterns.
Detection of Inherited Mutations: Whole Exome Sequencing is valuable in identifying genetic mutations responsible for Mendelian disorders passed down through families.
Research on Rare and Novel Variants: It supports the discovery of uncommon or newly identified variants that may be linked to various diseases, aiding in the development of targeted therapies.
Pharmacogenomics and Drug Development: By analyzing how genetic differences affect drug response, Whole Exome Sequencing contributes to the creation of personalized treatments tailored to an individual’s genetic makeup.
Cancer and Complex Disease Studies: Whole Exome Sequencing is widely used in cancer research to uncover mutations driving tumor growth and in exploring the genetic basis of complex disorders involving multiple genes.

In how many days the WES test reports will come?

At My Genetic DNA Center, You can expect the delivery of your results in 3 to 4 weeks, providing you with valuable insights into your genetic profile. Furthermore, we will include the raw data alongside the results, enabling you to actively explore and analyze the information.

Conclusion:

Whole Exome Sequencing (WES) represents a breakthrough in the field of molecular diagnostics, offering a detailed look into the most critical parts of our DNA. Whole Exome Sequencing (WES) has transformed the understanding and management of rare genetic diseases and unexplained conditions. As genomic technologies advance, clinicians increasingly adopt WES due to its growing accessibility, affordability, and integration into routine medical care.