Tay-Sachs Disease

What is UNITY Fetal Risk™ Screen for Tay-Sachs disease?

UNITY Fetal Risk Screen is a carrier screening and fetal risk assessment for your pregnancy all in one convenient blood test. The first step is identifying if you are a carrier for Tay-Sachs disease. If you are not a carrier for Tay-Sachs disease, your baby’s risk of having Tay-Sachs disease is extremely low. If you are a carrier and currently pregnant, UNITY Fetal Risk Screen will automatically perform a fetal risk assessment using cfDNA to tell you if your baby’s risk of having Tay-Sachs disease is high or low.

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The American College of Obstetricians and Gynecologists recommends Tay-Sachs disease carrier screening for anyone planning to start a family or those who are already pregnant that have Ashkenazi Jewish, French-Canadian or Cajun ancestry and/or family history of Tay-Sachs disease.

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What is Tay-Sachs disease?

Tay-Sachs disease is an inherited condition that affects the nervous system. It occurs when the body is unable to break down a specific type of fat, causing it to build up in the brain and nerve cells. Common symptoms of Tay-Sachs disease include muscle weakness that worsens over time, loss of motor skills, difficulty swallowing, and seizures. 

There are three types of Tay-Sachs disease: infantile, juvenile, and late-onset. The range of symptoms can be broad. Genetic testing can sometimes predict which condition is more likely, however, it cannot always provide definitive answers. 

The infantile form is the most common and most severe type of Tay-Sachs disease, with symptoms typically appearing around six months of age. The disease progresses quickly and most children with the infantile form of Tay-Sachs Disease do not live beyond four or five years of age. 

The juvenile form of Tay-Sachs disease usually appears in children between ages 2 and 10 and progresses more slowly but still leads to a shortened lifespan. The late-onset type is the mildest, with symptoms that can start in adolescence or adulthood and progress slowly, sometimes allowing for a typical lifespan. 

Currently, there is no cure for Tay-Sachs Disease, but treatments focus on managing symptoms and providing supportive care. This may include medications to help control seizures, physical therapy, and nutritional support to ensure proper feeding.

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How is Tay-Sachs disease inherited?

Tay-Sachs disease is an autosomal recessive condition. This means that a person must inherit two non-functional HEXA genes, one from each of their parents, to be affected with Tay-Sachs disease. Parents who carry one functional gene and one non-functional gene are known as carriers and typically show no symptoms.

If both parents are carriers of Tay-Sachs disease, there is 25% chance with each pregnancy that their child will inherit two non-functional genes and develop Tay-Sachs disease, a 50% chance that their child will inherit one non-functional gene and be a carrier like their parents, and a 25% chance that their child will inherit two functional genes and not be affected or a carrier.

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Who should consider screening for Tay-Sachs disease? 

Carrier screening for Tay-Sachs disease is recommended for anyone planning to start a family or those who are already pregnant that have Ashkenazi Jewish, French-Canadian or Cajun ancestry and/or family history of Tay-Sachs disease. UNITY Fetal Risk Screen is a simple blood test to determine your carrier status and the risk of having a baby with Tay-Sachs disease. If your results show a high risk of any of the conditions screened, you can discuss additional testing either before or after your delivery with your healthcare provider or one of our genetic counselors. 

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UNITY Fetal Risk Screen Carrier Screening & Fetal Risk Assessment (cfDNA for recessive conditions) workflow

Test as early as 9 weeks‍

Your blood sample can be collected in the doctor’s office, at a local lab, or through our mobile services. Your blood sample is shipped to our CAP/CLIA certified laboratory in northern California.

UNITY Aneuploidy™  Screen + UNITY Fetal RhD™  and Fetal Antigen™  results as early as 10 weeks‍

Within about one week from lab receipt, your doctor will receive the baby’s risk score for aneuploidies (chromosome conditions) and fetal RhD and fetal antigens (if added). You will receive a text or email indicating your results are available on our portal, or your healthcare provider may call you with the results.

Carrier status + fetal risk assessment results as early as week 11‍

Within about two weeks from lab receipt, your doctor will receive the results of your maternal carrier status testing and fetal risk assessment. If you were found to be a carrier for any of the recessive conditions, fetal risk assessment is automatically run to determine your baby’s risk of being affected. You will receive a text or email indicating your results are available on our portal, or your healthcare provider may call you with the results.

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What do Tay-Sachs disease screening results mean?

Your UNITY Fetal Risk Screen results will tell you if you are a carrier for Tay-Sachs disease, or other recessive conditions. Then, if you are currently pregnant and a carrier for one or more of the conditions screened, a fetal risk assessment using cfDNA will automatically be performed on your sample. Your UNITY Fetal Risk Screen report  will show your baby's risk for being affected with Tay-Sachs disease.  

If your results show a high-risk, your healthcare provider will discuss the recommended confirmatory testing that can be performed before or after delivery.

UNITY Fetal Risk Screen results are not diagnostic, so there is always the option for additional confirmatory testing to be performed. You can discuss your options and recommendations with your provider or one of our genetic counselors:

• Before Birth:
  Testing during pregnancy can be performed by obtaining a sample of placenta (chorionic villus sampling or CVS) or fluid around your baby (amniocentesis) which both contain DNA that is representative of your baby.  A CVS is ideally performed between 10 to 13 weeks in pregnancy while an amniocentesis is typically performed between 15 to 24 weeks in pregnancy.  Both procedures are generally safe, but have a small risk for pregnancy complications, including miscarriage.

• After Birth: 
  Testing for your baby can be performed after birth through a blood test as a newborn or with your baby’s pediatrician.

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Frequently Asked Questions

Is there a cure for Tay-Sachs disease? 

Currently, there is no cure for Tay-Sachs disease. However, clinical trials are ongoing for gene and enzyme replacement therapies to slow progression of the disease. 

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How is Tay-Sachs disease treated? 

Treatment is supportive and mainly focuses on managing the symptoms of Tay-Sachs disease with medications, therapies and nutrition support. Individuals with Tay-Sachs disease are managed by a multidisciplinary care team, including neurologists, gastroenterologists, and other healthcare providers.

What are the different forms of Tay-Sachs disease? ‍

Infantile form: This is the most common and severe type of Tay-Sachs disease, with symptoms typically appearing in the first three-six months of age. Progression is typically quick and results in early death in childhood. Common symptoms include muscle weakness, loss of motor skills, seizures and other neurological concerns. 

Juvenile form:  This form of Tay-Sachs disease usually appears in children between ages 2 and 10 and progresses more slowly, but still leads to a shortened lifespan. Common symptoms include poor muscle control, progressive speech problems and loss of speech, seizures and other neurological concerns. 

Late-onset form: This is the mildest form of Tay-Sachs disease, with symptoms starting in adolescence or adulthood. Progression is slow, sometimes allowing for a typical lifespan. Common symptoms include poor coordination, speech problems, tremors and other neurological concerns.

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Treatment & Resources

• National Organization of Rare Diseases
• Medline Plus
• National Tay Sachs and Allied Diseases Association