Clinical WES

Has your doctor suggested a test called Whole-Exome Sequencing (or WES) for you or a family member?


 This guide is designed to give you more information about WES. If you have questions about the information contained here, please ask your doctor or contact us directly (phone number: +48 22 644 60 19).

Genetics

Every living organism stores its genetic information in deoxyribonucleic acid, known as DNA. Genetic information is encoded in the order in which the four units (nucleotides - the letters of the genetic code: A, C, G, T) that make up the DNA chain  occur. Our human genome consists of 3 billion of these letters, written down on pieces of paper it takes up as many as 400 volumes of encyclopaedias that instruct our body how to grow and function.

Our DNA is organised into 23 pairs of chromosomes, each pair containing one chromosome from each parent. These chromosomes contain genes, which are divided into exons and introns. Exons are the coding regions that contain the instructions for the production of proteins essential to our bodies. Introns, on the other hand, are non-coding regions that can also contain important information about how and where a gene should be used. The entire set of genes, including both exons and introns, is our genome. Exons make up only a small percentage of this total (about 1%-2%). Our exome, which is the set of all exons, is different from other people's exome, which makes each of us unique. Sometimes, however, we may have one or more genetic differences, or genetic variants, which cause one or more genes to stop working or work differently than expected. When this happens, these genetic variants can cause a genetic disease.

What is whole-exome sequencing (WES)?

Most of the genetic variants that cause genetic diseases are located in the exome, so WES involves sequencing, or reading the exome, which is the protein-coding part. This is the most diagnostically relevant information due to the fact that approximately 85% of genetic variants responsible for the occurrence of genetic diseases are located within it. One could say that with WES, it is possible to identify the presence of spelling mistakes or typos in the text of a book. WES is a genetic test that examines the genetic information contained in all our 20 000 genes in a single test. This makes a fundamental difference to other genetic tests, which can only analyse one gene (or a small number of genes) at a time.

WES testing is performed using a technology called Next-Generation Sequencing (NGS). A sample of the patient's blood or saliva is taken and DNA is isolated from it. The patient's DNA is then compared to a reference genome sequence, which represents a 'healthy' human DNA sequence, to detect any differences between the patient's DNA and the reference DNA. If there are any differences, they are analysed by our experts i.e. diagnosticians, geneticists and experienced clinical geneticists.

Who should have WES testing?

WES testing can be carried out during pregnancy, in childhood or in adulthood. It is usually recommended for the following reasons:
- in clinically unclear cases or when the estimated cost of targeted diagnostics is higher than the cost of WES;
- a specific genetic disease is suspected, but available, targeted genetic tests have failed to confirm the diagnosis;
- when there is a suspicion that you or your child has a genetic disease;
- when there are many different genes that may be causing your or your child's symptoms;
- if you or your child has a complex medical history that affects multiple organs and/or body systems.

Who should not undergo WES testing?

WES may not be the ideal test for you or your child if the condition does not have a genetic basis, or if you or your child have a known genetic disorder that is or is likely to be caused by a damage to a single gene. Talk to your doctor about which test is right for you or your child.

What makes the WES offered at Genomed SA different from WES at other laboratories?

Many genetic laboratories offer WES testing. Sometimes it can be difficult to decide why you should choose one laboratory over another. At Genomed SA, we guarantee the highest quality of analysis and interpretation of results, thanks to the experience of our specialists. For more than 15 years, we have supported doctors and patients, having issued results of more than 60,000 genetic tests. We are the main creator of the first Polish reference database POLGENOM. It is the only genomic database for the Polish population, which is unique due to the combination of clinical and genomic data, based on the complete genomes of 126 healthy, long-lived Poles (aged over 90), containing an individual set of clinical and biochemical data for each genome. Having access to such data allows an extensive analysis of genetic variants and exclusion of variants common in the Polish population. In our WES analysis, we first check for the presence of known pathogenic variants registered in databases.  Our testing additionally includes the analysis of changes in gene structure - so-called copy number variants (CNVs) and clinically relevant variants in non-coding regions, which are not covered by standard WES testing.
During pre- and post-test genetic counselling, we carefully explain any limitations that WES may have. We confirm a pathogenic genotype by another method and investigate the carriership of pathogenic variants in other family members (if we have a suitable material). We report your results in a comprehensive and easy-to-understand manner.


Our offer:


Clinical Exome
Test code: EXOME-1


Clinical Exome MAXIMUM
 The most comprehensive clinical WES including the mitochondrial genome analysis

Test code: EXOME-MAX