Tay-Sachs Disease (HEXA) 7 Mutations
Ordering Recommendation

Molecular (DNA) test to confirm common pathogenic and pseudodeficiency mutations for Tay Sachs disease. For initial testing for Tay Sachs, refer to Hexosaminidase A Percent and Total Hexosaminidase in Leukocytes (2008125). For carrier screening of common Ashkenazi Jewish-related diseases, please refer to Ashkenazi Jewish Diseases (BLM, ASPA, IKBKAP, FANCC, GBA, MCOLN1, SMPD1, HEXA), Common Mutation Panel (0051415).

Polymerase Chain Reaction/Primer Extension
Tue, Thu
7-10 days
New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).  
Specimen Preparation
Transport 3 mL whole blood. (Min: 1 mL)  
Storage/Transport Temperature
Unacceptable Conditions
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable  
Reference Interval
By report
Interpretive Data
Background information for Tay-Sachs Disease (HEXA) 7 Mutations:
Lysosomal storage disease that in its severe form leads to loss of motor skills beginning at three to six months of age that progresses to blindness, seizures and total incapacitation and death by 4 years of age. A milder disease with later onset and slower progression is seen in affected adults. Adult-onset Tay-Sachs is associated with variable neurological findings including: progressive dystonia, spinocerebellar degeneration, motor neuron disease and bipolar form of psychosis.
1 in 3000 Ashkenazi Jewish individuals, unknown in other ethnicities.
Autosomal recessive.
PathogenicHEXA gene mutations.
Mutations Tested:
Four severe (7.6kb del, c.1073(+1)G>A, p.Y427Ifs (c.1274_1277dup TATC) c.1421(+1)G>C; one mild p.G269S (c.805G>A); and two pseudodeficiency alleles p.R247W (c.739C>T) and p.R249W (c.745C>T).
Clinical Sensitivity:
94 percent in Ashkenazi Jewish individuals, unknown in other ethnicities.
Multiplex polymerase chain reaction and Detection Primer Extension
Analytical Sensitivity and Specificity:
Greater than 99 percent.
HEXAmutations other than those specified above will not be detected. Diagnostic errors can occur due to rare sequence variations.

Compliance Statement C: For human genetic inheritable conditions and mutations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
CPT Code(s)
Component Test Code*Component Chart NameLOINC
0051430Tay-Sachs Disease (HEXA) 7 Mut, Allele 138900-7
0051431Tay-Sachs Disease (HEXA) 7 Mut, Allele 238900-7
0051432Tay-Sachs Disease (HEXA) 7 Mut, Interp51773-0
2001315Tay-Sachs Disease (GBA) 7 Mut, Specimen31208-2
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
  • Hexosaminidase A
  • Hexosaminidase A Deficiency DNA assay
  • TSD molecular assay