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Tay-Sachs Disease

Alternate test name
  • TSD
  • Hexosaminidase A deficiency
  • HEXA deficiency
Gene name / Alternate gene name
  • HEXA
  • TSD
Hexosaminidase A
Lab area
Genome Diagnostics - Molecular Genetics
Method and equipment
Targeted analysis of recurrent mutations; Sequencing
Expected turn-around time
Pregnancy/STAT: 2-3 weeks Routine: 4-6 weeks
Specimen type

Blood; gDNA. 

For details about specimen requirements, please refer to: Specimen Type & Requirements (PDF).

Specimen requirements
  • Blood: 5-10 mL in EDTA, 0.5 mL in EDTA (neonate); 
  • DNA-minimum 10 ug in 100 uL low TE (pH8.0)
Storage and transportation

Room Temperature

For details about specimen requirements, please refer to: Specimen Type and Requirements

Special requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment >48 hours, ship on ice.

Shipping information
The Hospital for Sick Children
Division of Genome Diagnostics
555 University Avenue, Black Wing, Room 3416
Toronto, ON
M5G 1X8
Phone: 416-813-7200 ext. 2
Hours: Monday to Friday, 8 a.m. to 4:30 p.m.
Off hours: Please send to Rapid Response Laboratory, 555 University Avenue, Room 3642
Email Molecular Lab:
Email Cytogenetics:
Background and clinical significance

Tay-Sachs disease (TSD) is characterized by progressive weakness and loss of motor skills beginning between three and six months of age. Over time, signs of progressive neurodegeneration occur, such as seizures, blindness, and paralysis, usually leading to death before the age of four. TSD is caused by a deficiency of the enzyme hexosaminidase-A (Hex-A). Deficiency of the Hex-A enzyme can also be identified by biochemical enzyme tests. TSD is an AR disorder caused by mutations in the HEXA gene, located on chromosome 15 (15q23-q24). Three mutations in the HEXA gene account for more than 99% of the mutations seen in AJ individuals affected with TSD. TSD is also seen at a comparable frequency in other ethnic groups including French Canadians and Cajuns. Two mutations that are seen more frequently in the French Canadian population are also screened for as part of this panel.

See related information sheet:  Ashkenazi Jewish Screening Panel

Disease condition

Tay-Sachs Disease (part of the Ashkenazi Jewish screening panel)

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