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Genetic Labs

Houston, Texas

Genetic Laboratory
Medical Genetics Laboratories
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Medical Genetics Test Details

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Whole Exome Sequencing
Test Information: Indications for Testing
The Whole Exome Sequencing (WES) test is ordered by a physician and must be accompanied with a consent form and detailed clinical information. In general, the test is used when a patient's medical history and physical exam findings strongly suggest that there is an underlying genetic etiology. In some cases, the patient may have had an extensive evaluation consisting of multiple genetic tests, without identifying an etiology. In other cases, a physician may opt to order the Whole Exome Sequencing test early in the patient's evaluation in an effort to expedite a possible diagnosis. See (FAQ) for additional details.

- Patient with undiagnosed genetic syndrome

Note: Parental samples are required to interpret proband WES results. See requisition for sample requirements and further details.
Test Details
Test Code: 1500
Special Notes: The Whole Exome Sequencing test is a highly complex test that is newly developed for the identification of changes in a patient's DNA that are causative or related to their medical concerns. In contrast to current sequencing tests that analyze one gene or small groups of related genes at a time, the Whole Exome Sequencing test will analyze the exons or coding regions of thousands of genes simultaneously using next-generation sequencing techniques.

The exome refers to the portion of the human genome that contains functionally important sequences of DNA that direct the body to make proteins essential for the body to function properly. These regions of DNA are referred to as exons. There are approximately 180,000 exons in the human genome which represents about 3% of the genome. These 180,000 exons are arranged in about 22,000 genes. It is known that most of the errors that occur in DNA sequences that then lead to genetic disorders are located in the exons. Therefore, sequencing of the exome is thought to be an efficient method of analyzing a patient's DNA to discover the genetic cause of diseases or disabilities. Additionally, the WES includes a mitochondrial genome sequencing. Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA. This genetic material is known as mitochondrial DNA or mtDNA. In humans, mitochondrial DNA represents a small fraction of the total DNA in cells. Many genetic conditions are related to changes in particular mitochondrial genes.

The principle of the test is to sequence nucleotide by nucleotide, the human exome of an individual to a depth of coverage necessary to build a consensus sequence with high accuracy. This consensus sequence is then compared to standards and references of what is normal in the population and the result is interpreted by board-certified laboratory directors and clinicians. By sequencing the exome of a patient and comparing it to normal reference sequence, variations in an individual's DNA sequence can be identified and related back to the individual's medical concerns in an effort to discover the cause of the medical disorder.
Technical Information
Methodology: Exome Capture and Next Generation Sequencing
Sample & Shipping Information
Test Requisition: Whole Exome Sequencing
Specimen Type: Blood
Requirements: Draw blood in an EDTA (purple-top) tube(s). Send at least 5cc (children) or 10cc (adults).
Shipping Conditions: Ship at room temperature in an insulated container by overnight courier. Do not heat or freeze. Sample must arrive within 48 hrs.

Specimen Type: Cultured Skin Fibroblast
Requirements: Send 2 T25 flasks at 80-100% confluence.
Shipping Conditions: Ship at room temperature in an insulated container by overnight courier. Do not heat or freeze.

Specimen Type: Purified DNA
Requirements: Send at least 20ug of purified DNA (minimal concentration of 50ng/uL; A260/A280 of ~1.7).
Shipping Conditions: Ship at room temperature in an insulated container by overnight courier. Do not heat or freeze.

Turn Around Time: 15 weeks
Billing Information
List Price: *For Insurance or Institutional Prices, please call.
CPT Codes: 81400x1, 81401x1, 81402x1, 81403x1, 81404x1, 81405x1, 81406x1, 81407x1


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