Tay-Sachs (infantile Onset)
Affected Jewish population(s):
Ashkenazi
Carrier frequency in affected Jewish population(s):
1 in 25 to 30 Ashkenazi Jews.
Presence in other population groups:
Celtic (Irish), French & French Canadian, Cajun and Pennsylvania Dutch. Carrier frequency 1 in 250 to 1 in 300.
Symptoms:
Progressive weakness, loss of motor skills, decreased attentiveness, increased startle response with progressive evidence of neurodegeneration, including seizures, blindness, spasticity, and eventual total incapacitation and death.
Age of onset of symptoms:
3 to 6 months of age
Impact on lifespan:
Average lifespan less than 4 years
What causes the features of the disease:
Deficiency in the enzyme Hexosaminidase A (HEX A), which leads to the buildup of harmful substances in the brain.
Treatment or management:
Supportive, protection of airway, control of seizures.
Carrier screening:
DNA analysis by blood test: in Ashkenazi Jewish individuals three common mutations account for between 92% and 94% of carriers. Enzyme analysis, in addition to DNA analysis, is recommended for Tay-Sachs carrier screening.
Tay-Sachs Disease (Late Onset)
Affected Jewish population(s):
Ashkenazi
Carrier frequency in the affected Jewish population(s):
Unknown
Presence in other population groups:
All ethnic, racial and religious groups
Symptoms:
Poor coordination, tremor, slurred speech at onset, and, with advancing age, slow progression with development of variable neurological symptoms including ataxia, loss of coordination, unsteady gait, muscle weakness, and progressive dystonia. In the 4th decade of life, mental and behavioral abnormalities include bipolar disorder and psychoses.
Age of onset of symptoms:
Childhood to adolescence
Impact on lifespan:
Long term survival to adult years
What causes the features of the disease:
Hexosaminidase A deficiency with residual but low activity of the HEX A enzyme, which leads to the buildup of harmful substances in the brain.
Treatment or management:
For older individuals who have psychiatric manifestations, conventional antipsychotic or antidepressant therapy may be used, but the clinical response is unpredictable and generally poor. Treatment with lithium salts and electroconvulsive therapy has been reported to be beneficial in temporarily reducing the episodes of psychotic depression.
Carrier screening:
Hexosaminidase A (HEX A) enzyme analysis will accurately detect the deficiency of HEX A and the low activity of the enzyme. DNA analysis by blood test identifies two mutations linked with late-onset Tay-Sach disease. Many of the carriers of the late onset form of Tay-Sachs disease have been detected during screening programs for Infantile Tay-Sachs Disease.
For more information:
National Tay-Sachs & Allied Diseases Association New York Area, Inc.: www.ntsad-ny.org
212-431-0431 or 888-354-7788
National Tay-Sachs and Allied Diseases Association: www.ntsad.org
Mathew Forbes Romer Foundation:
www.mfrfoundation.org
561-477-0337
Cure Tay-Sachs Foundation: http://www.curetay-sachs.org
Tay-Sachs Gene Therapy Consortium / National Human Genome Research Institute
http://www.genome.gov/10001220
Wikipedia: http://en.wikipedia.org/wiki/Tay-Sachs_disease
Cameron & Hayden Lord Foundation: http://www.lordfoundation.org
NIH: http://ghr.nlm.nih.gov/condition/tay-sachs-disease
