8 - 14 days (If cultured cells are needed, an additional 7-12 days may be required. Additional culture fee may be included.) Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Tay-Sachs disease mutation analysis tests for 8 mutations (6 disease-causing mutations and 2 pseudodeficiency alleles). We perform Tay-Sachs enzyme analysis (hexosaminidase A) in conjunction with Tay-Sachs mutation analysis to provide a carrier detection rate of 97–98% in the Ashkenazi Jewish population. disease occurs at an increased frequency in individuals of Ashkenazi Jewish and French-Canadian descent. It is a lysosomal storage disorder that results in untreatable neurological degeneration and, in the common infantile form, death by 5 years of age.
Prenatal testing: Integrated Genetics clients should call 800-848-4436 to speak to a laboratory genetic coordinator before collecting any specimens. In some circumstances, specimens from other family members may be required. All prenatal specimens (including cord blood) must be accompanied by a maternal blood or mouthwash specimen for analysis of possible maternal cell contamination. Discard first 2 mL; then 10 mL amniotic fluid in 15 mL orange-top polypropylene tube, 10-15 mg chorionic villi in laboratory-provided screw-top tubes with sterile transport medium or one T-25 flask of confluent cells. Additional sample must be obtained for back-up culture at one of our cytogenetics laboratories or another facility. If additional testing is desired, more amniotic fluid is needed. For example, chromosome analysis requires an additional 15-25 mL (see Cytogenetics – Amniotic Fluid Chromosome Analysis test page) and AFAFP requires an additional 2 mL (see Amniotic Fluid Alpha-Fetoprotein - AFAFP test page).
False-positive and false-negative results may occur for reasons that include genetic variants, blood transfusions, bone marrow transplantation, erroneous representation of family relationships, or contamination of a fetal sample with maternal cells.
Polymerase chain reaction (PCR); primer extension; flow-sorted bead array analysis
Couples who are planning a pregnancy or who are already pregnant may decide to have testing to find out if they are carriers and at risk of having a baby with Tay-Sachs disease. It is standard of care to offer carrier screening to individuals of Ashkenazi Jewish descent for Bloom syndrome, Canavan disease, cystic fibrosis, familial dysautonomia, Fanconi anemia group C, Gaucher disease, mucolipidosis type IV, Niemann-Pick disease type A and Tay-Sachs disease. If both parents are found to be carriers, prenatal diagnosis by CVS or amniocentesis is available. Our Tay-Sachs disease mutation analysis tests for 8 mutations (6 disease-causing mutations and 2 pseudodeficiency alleles). We perform Tay-Sachs enzyme analysis (hexosaminidase A) in conjunction with Tay-Sachs mutation analysis to provide a carrier detection rate of 97–98% in the Ashkenazi Jewish population.
Information on collection, storage, and volume
Whole blood or mouthwash (see specimen kit for detailed instructions), amniotic fluid, chorionic villi
Postnatal: 10 mL whole blood or mouthwash / Prenatal: 10 mL amniotic fluid in orange-top polypropylene tube, 10-15 mg chorionic villi in laboratory provided screw-top tubes with sterile transport medium or one T-25 flask of confluent cells.
Lavender-top (EDTA) tube or yellow-top (ACD-A) tube or mouthwash kit
Maintain specimen at room temperature.
Causes for Rejection
Frozen specimen; hemolysis; quantity not sufficient for analysis; improper container; unlabeled or mislabeled specimen
Mouthwash collection: Patient should not eat, drink, smoke or chew gum for at least one hour prior to collection. (See specimen kit for detailed instructions). Mouthwash samples can be sent when ordering up to two tests. When ordering more than two tests, blood samples are required. 10 mL of Scope® mouthwash that has been swished vigorously for at least 1 minute. Collect in orange-top 50 mL polypropylene tube.