Tay-Sachs Disease

Tay-Sachs disease (TSD) is a lysosomal storage disorder with symptoms ranging from an acute infantile form (classic TSD) to subacute juvenile and adult onset forms with later onset and slower disease progression. Infants with classic TSD generally appear normal at birth. At 3-6 months of age motor weakness, myoclonic jerks and an exaggerated startle reaction are usually the presenting features followed by developmental retardation and regression, paralysis, dementia and blindness with death by the second or third year of life. A cherry-red macula is a typical fundoscopic finding and, histologic examination reveals the lysosomal accumulation of GM2 gangliosides represented as distended, ballooned neurons in the central nervous system. The juvenile and adult forms have more variable neurologic findings, including progressive dystonia, spinocerebellar degeneration, motor neuron disease, and in some individuals with the adult onset form, a bipolar form of psychosis. The juvenile and adult onset forms differ from each other primarily by the impact of the disease on intelligence, which is minimal through much of the course of the adult form. The carrier frequency in Ashkenazi Jews is approximately 1 in 30, while the carrier in Sephardic Jews and non-Jews is approximately 1 in 250 to 1 in 300. Other groups that are relatively genetically isolated have also been found to have carrier frequencies similar to or higher than that observed in Ashkenazi Jews including French Canadians from eastern Quebec, Cajuns from Louisiana and the Old Order Amish in Pennsylvania.

Tests Available

Forms and Documents

Test Details

HEXA
  • Confirmation of biochemical diagnosis especially in those with borderline enzyme activity
  • Full sequence analysis for non-Jewish partners of individuals who are known to be a mutation carrier
  • Carrier testing
  • Prenatal diagnosis in at risk pregnancies
  • Capillary Sequencing Reflex to Exon Array CGH

Ordering

519
4-5 weeks
2-5 mL Blood - Lavender Top Tube
Oral Rinse (30-40 mL)|Buccal Swabs

Billing

81406x1
No
Yes
  • 330.1 Tay-Sachs disease hexosaminidase A deficiency; Cerebral lipidoses
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References

  1. Kaback, M. (Updated [May 19, 2006]) Hexosaminidase A Deficiency In: GeneReviews at Genetests: Medical Genetics Information Resource (database online). Copyright, University of Washington, Seattle. 1997- 2007. Available at http://www.genetests.org.
  2. Maegawa et al., (2006) Pediatrics 118:e1550-e1562.
  3. Giraud et al., (2010) Biochem Biophys Res Commun 392:599-602.
  4. Montalvo et al., (2005) Hum Mutat 26:282.
  5. Park et al., (2010) Pediatr Res 67:217-20.
  6. Myerowitz, R. And Hogikyan, N. (1986) Science 232:1646-1648.
  7. Hechtman et al., (1992) Hum Genet 90:402-406.
  8. Triggs-Raine et al., (1990) N Engl J Med 323:6-12.
  9. Akerman et al., (1992) Hum Mutat 1:303-309.
  10. Cao et al., (1997) J Biol Chem 272:14975- 14982.
  11. Braekeleer et al., (1992) Hum Genet 89:83-87.