What are other Names for this Test? (Equivalent Terms)
- Bilirubin-Specific UDPGT Isozyme 1 Mutation Analysis Test
- UDP Glucuronosyltransferase 1 Family, Polypeptide A1 Mutation Analysis Test
- UGT1.1 Mutation Analysis Test
What is UGT1A1 Mutation Analysis Test? (Background Information)
- UGT1A1 mutation refers to an alteration in the UGT1A1 gene. It is associated with jaundice and disorders of bilirubin metabolism
- The UGT1A1 gene gives instructions for the UGT1A1 protein. The UGT1A1 protein helps convert a compound called bilirubin into a stable, nontoxic form and removes it from the body
- Bilirubin is a compound produced from the breakdown of a chemical in red blood cells called heme. Heme helps bind red blood cells that bind oxygen and transport it throughout the body
- When red blood cells get damaged, or worn, they are recycled. Their heme is converted into bilirubin in the liver and, in normal conditions, excreted through the bile and urine
- Before being able to be excreted, bilirubin must first be converted into a nontoxic form - conjugated bilirubin. The process of bilirubin conversion is called glucuronidation
- The UGT1A1 protein is responsible for bilirubin glucuronidation. UGT1A1 stands for UDP-glucoronosyltransferase 1A1. The process takes place in the liver
- Abnormalities in the UGT1A1 gene may result in a UGT1A1 protein that is defective. The defective UGT1A1 protein may be unable to process bilirubin
- Accumulations of bilirubin may cause jaundice, a yellowing of the whites of the eyes. It may lead to nervous system damage (as bilirubin is toxic to neurons), as well as liver damage
- The UGT1A1 Mutation Analysis Test is used to detect abnormalities in the UGT1A1 gene. It helps investigate the cause of jaundice and detect bilirubin metabolism disorders
Molecular testing, in general, can be performed using a variety of methods. Some of these methods include:
- In situ hybridization techniques, such as fluorescence in situ hybridization (FISH)
- Immunohistochemistry (IHC)
- Next-generation sequencing (NGS)
- Methylation profiling
- Polymerase chain reaction (PCR)
- Comparative genomic hybridization (CGH)
- Karyotyping including spectral karyotyping
- mRNA analysis
- Tissue microarrays (TMAs)
- Southern blot test
- Northern blot test
- Western blot test
- Eastern blot test
The methodology used for the test may vary from one laboratory to another.
Note: Molecular testing has limitations depending on the method being used, 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 UGT1A1 Mutation Analysis Test?
- The clinical indications for performing the UGT1A1 Mutation Analysis Test include yellow skin and eyes in newborns and adults
In general, the molecular genetic testing is undertaken in the following situations:
- To assist (and in some cases, confirm) the initial diagnosis
- To check for or ascertain a family history of the condition
- To distinguish other conditions that have similar features (signs and symptoms)
- To help determine treatment options
How is the Specimen Collected for UGT1A1 Mutation Analysis Test?
The type and source and specimen sample requirements will depend on the preference of the individuals and the preference of the testing lab. Thus, it may vary from one individual to another and from one lab to another. Therefore, it is important to contact the testing lab for exact specimen requirements, before initiating the collecting and testing process.
Following is the specimen collection process for UGT1A1 Mutation Analysis Test:
- Sample on which the test is performed may include:
- Peripheral blood in individuals showing signs and symptoms suspected of the condition
- Bone marrow biopsy specimen
- For mitochondrial DNA testing, usually a muscle biopsy or a liver biopsy is preferred
- In case of expectant mothers, prenatal testing through amniotic fluid and chorionic villi sampling
- Fetal cord blood
- Fresh tissue from biopsy
- Fresh tissue from autopsy sample
- Fresh tissue from fetal demise
- Buccal brushes: Using the kit that is provided by the testing laboratory, buccal brushes can be used to collect the specimen, by scraping the inner cheek lining (buccal mucosa)
- Oral rinse specimens
- Body fluids such as saliva, tears, and semen
- Dried blood spots: This specimen type is usually requested in situations where the collection and/or shipping of whole blood is not practical
- In some cases, hair samples (with attached roots), finger nails, and buccal swabs, may be acceptable
- Formalin-fixed paraffin-embedded solid tumor tissue (FFPE tumor tissue), often referred to as paraffin block of the tumor
- Products of conception sample from aborted pregnancy
- Process of obtaining the sample: As outlined by the laboratory testing facility
- Preparation required: As outlined by the laboratory testing facility
Limitations of specimen while testing for the condition
- For blood specimens: Individuals, who have received platelet transfusions, red blood transfusion, or white blood (leukocyte) transfusion, should wait at least 4 weeks before providing a blood specimen
- The following specimens may not be acceptable in individuals who have received heterologous bone marrow transplant (in the past):
- Peripheral blood samples
- Oral rinse specimens
- Bone marrow biopsy specimens
- Testing should not be performed on a transplanted organ/specimen, since the genetic material belongs to the donor and not to the individual being tested
- Formalin-fixed paraffin-embedded solid tumor tissue: In many cases, FFPE tissue blocks are usually not acceptable. Please contact the testing lab to ascertain, if it is an acceptable sample specimen
- In some cases, a different source of specimen may be acceptable to the laboratory performing the test
Occasionally, additional samples may be required to either repeat the test or to perform follow-up testing.
Turnaround time for test results
- Depending on the location of testing, it may take from 2 to 8 weeks from the time of sample collection, to obtain the test results
Sample storage information
- Many hospitals preserve the paraffin blocks for at least 7 years
- In general, older paraffin blocks (over 5 years) may affect the detection of specific mutations, due to degradation of the tissue specimen over time
Cost of UGT1A1 Mutation Analysis Test:
- 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, whether your healthcare provider/facility is in-network or out-of-network of your insurance company
- 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, if required
What is the Significance of the UGT1A1 Mutation Analysis Test Result?
The presence of a mutation in the UGT1A1 gene indicates a positive result for the UGT1A1 Mutation Analysis Test. This may point to a diagnosis of any of the following:
- Crigler-Najjar syndrome
- Gilbert syndrome
- Warfarin resistance
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:
- The UGT1A1 gene resides on a position of the chromosome called 2q37.1 i.e., the long (q) arm of chromosome 2 in location 37.1
- Many laboratories may not have the capability to perform this test. Only highly-specialized labs with advanced facilities and testing procedures may offer this test
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.
What are some Useful Resources for Additional Information?
The following DoveMed website link is a useful resource for additional information:
Please visit our Laboratory Procedures Center for more physician-approved health information:
References and Information Sources used for the Article:
https://ghr.nlm.nih.gov/primer/testing/genetictesting (accessed on 05/10/2017)
https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5806a1.htm (accessed on 05/10/2017)
http://www.nature.com/gim/journal/v10/n5/full/gim200852a.html (accessed on 05/10/2017)
http://pediatrics.aappublications.org/content/106/6/1494 (accessed on 05/10/2017)
Alaee, E. (2016). The Association between Prolonged Jaundice and UGT1A1 Gene Polymorphism (G71R) in Gilbert's Syndrome. JOURNAL OF CLINICAL AND DIAGNOSTIC RESEARCH. doi:10.7860/jcdr/2016/19004.8810
UGT1A1 gene - Genetics Home Reference. (n.d.). Retrieved from https://ghr.nlm.nih.gov/gene/UGT1A1#
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