What are other Names for this Test? (Equivalent Terms)

• WGS (Whole-Genome Sequencing)

What is Whole-Genome Sequencing? (Background Information)

• Whole-Genome Sequencing (WGS) is a type of DNA sequencing, a specialized genetic testing technique used to detect chromosomal abnormalities that are too tiny to be detected using conventional microscopic studies
• In Whole-Genome Sequencing, an individual’s entire genome is sequenced. The results of this type of sequencing include the individual’s genes as well as the non-coding DNA
  • Non-coding DNA is composed of the same four letters as coding DNA, but it does not have the same meaning. Scientists are not completely sure of the function of non-coding DNA
  • A virtual panel can be used on the sequencing data so that analysis can be focused on variants in genes that are linked to the clinical features of the individual being tested
• The DNA in the cells is double-stranded. Each strand contains a mixture of four bases, namely A, T, C, and G. The bases of each strand bind with each other to hold the DNA together. The DNA is only able to bind if the bases on the two strands are complementary to each other
• Whole-Genome Sequencing is helpful in diagnosing complex diseases and disorders, cancers, and Mendelian diseases (such as cystic fibrosis, hemophilia, sickle cell anemia, etc.). WGS has also the potential to track disease outbreaks in real-time
• Whole-Genome Sequencing is a more expensive and time-consuming technique to detect genetic abnormalities. Also, presently, there may be only a limited number of labs offering this specialized genetic test

Note: Molecular testing has limitations due to the molecular method and genetic mutational abnormalities being tested. This can affect the results on a case-by-case basis. Consultation with your healthcare provider will help in determining the right test and right molecular method, based on individual circumstances.

What are the Clinical Indications for performing the Whole-Genome Sequencing?

Following are the clinical indicators for performing the Whole-Genome Sequencing analysis: 

• To assist (and in some cases, confirm) the initial diagnosis
• If there is a family history of the medical disorder/condition
• To help in determining treatment options
• When the results from whole exome sequencing are inconclusive 

WGS may be helpful in individuals with the following conditions/abnormalities:

• Craniofacial abnormalities
• Hearing and vision impairment
• Growth and developmental delays
• Speech and learning problems
• Intellectual disabilities - poor cognitive skills
• Skeletal abnormalities that involve the limbs, spinal cord, and skull
• Organ defects that involve the heart, lung, or brain
• Recurrent infections from poor immunity
• Unexplained illnesses

How is the Specimen Collected for the Whole-Genome Sequencing?

Following specimens may be collected for Whole-Genome Sequencing analysis:

• Blood
• Saliva
• Cheek swab cells

The specimen sample requirements may vary from lab to lab. Hence, it is important to contact the testing lab for exact specimen requirements, before initiating the testing process.

• Process of obtaining the sample: As outlined by the laboratory testing facility
• Preparation required: As outlined by the laboratory testing facility

Cost of Whole-Genome Sequencing:

• The cost of the test procedure depends on a variety of factors, such as the type of your health insurance, annual deductibles, co-pay requirements, out-of-network and in-network of your healthcare providers and healthcare facilities
• In many cases, an estimate may be provided before the test is conducted. The final amount may depend upon the findings during the test procedure and post-operative care that is necessary (if any)

What is the Significance of the Whole-Genome Sequencing Result?

The results of the Whole-Genome Sequencing (WGS) analysis may indicate if any of the following chromosomal anomaly has taken place:

• Deletion/microdeletion
• Duplication/microduplication
• Number and types of genes involved (such as deleted/duplicated)

The benefits of WGS include:

• It is helpful in the diagnosis of a condition; or, in understanding a condition better
• Personalized treatments may be provided
• Better prediction of long-term outcomes
• The information obtained through WGS may help determine if other family members have to be tested
• Understanding future risks for certain malignancies/disorders (not originally suspected by the healthcare provider)

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

Many laboratories may not have the capability to perform this test. Only highly-specialized labs with advanced facilities and testing procedures may perform this test.

Please visit our Laboratory Procedures Center for more physician-approved health information:

http://www.dovemed.com/common-procedures/procedures-laboratory/