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Leading the Fight to treat and cure
Tay-Sachs, Canavan, Sandhoff, GM1 and related diseases

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Tay-Sachs is a genetic disorder caused by the absence of beta-hexosaminidase (HexA). This missing enzyme causes cells to become damaged, resulting in progressive neurological disorders. A cure for Tay-Sachs does not yet exist but there are many strategies for managing life with Tay-Sachs.

There are 3 forms of Tay-Sachs:

The form is determined by the age of the individual when symptoms first appear. Only one form of Tay-Sachs occurs in a family. If a child has Infantile, older siblings are not at risk to develop Juvenile or Late Onset Tay-Sachs later in life.

 Classic Infantile Tay-Sachs -Symptoms appear around 6 months of age.

 Juvenile Tay-Sachs -Symptoms typically appear between ages 2 and 5, but can occur anytime during childhood.

 Late Onset Tay-Sachs -Symptoms typically appear in adolescence or early adulthood, but can appear later.

Who is at risk?

Anyone can be a carrier of Tay-Sachs. When both parents are carriers, each child has a 25% of having the disease. The carrier rate for the general population is 1/250. Some evidence suggests people of Irish / British Isle descent have an increased risk over the general population between 1/50 to 1/150. French Canadians, Louisiana Cajuns and Ashkenazi Jews are all considered high risk with a carrier rate of 1/27.

Talk to your doctor about Genetic Counseling to discuss your options before starting your family.

Explore More:

 Causes - the missing HexA enzyme

Research - ongoing research

 History of Tay-Sachs Disease - named for Warren Tay and Bernard Sachs

Infantile & Juvenile Family Support

Late Onset Support

Symptoms

The First Signs - A baby with classic Infantile Tay-Sachs appears normal at birth and typically continues to develop normally for the first six months of age. Around 6 months of age, development slows. Parents may notice a reduction in vision and tracking and the baby does not outgrow normal startle response.

A Gradual Loss of Skills - Infantile Tay-Sachs children gradually regress, losing skills one by one. Over time they are unable to crawl, turn over, sit or reach out. Other symptoms include loss of coordination, progressive inability to swallow and difficulty breathing.

By Age 2 and beyond - Most children experience recurrent seizures by age 2 and eventually lose muscle function, mental function and sight, becoming mostly non-responsive to their environment.

Diagnosis

Tay-Sachs disease is diagnosed through a blood test to check the level of Hexosaminidase A (HexA). A follow-up DNA test may be recommended.  Any doctor can order the Tay-Sachs HexA blood test. Often, diagnosis is made by a neurologist or geneticist.

Babies affected by the infantile forms of Tay-Sachs, Sandhoff, GM-1 and similar related allied diseases are frequently diagnosed by the cherry-red spot on the retina of the eye.  Initially many parents notice developmental delays but pediatricians often dismiss these concerns by stating "every baby develops differently" and "the baby will catch up." Often at about 10-14 months of age, children may start to exhibit trouble tracking and/or focusing with their eyes, so parents schedule an appointment for an eye exam.   The cherry-red spot is quickly seen and an initial diagnosis of Tay-Sachs or similar devastating disease is made.

Diagnosis can also be made by a neurologist or geneticists and the completion of a metabolic evaluation.

Management

There is no treatment or cure for Tay-Sachs disease but there are ways to manage symptoms. These range from life-extending interventions like a feeding tube to comfort measures like massage to promote relaxation.

Respiratory health and seizure management are the two main symptom management challenges in Infantile Tay-Sachs. Recommendations for managing the symptoms appear in Find Support.

Newly diagnosed families should read Finding Your Philosophy of Care, available through NTSAD. It will help parents develop a care plan and care goals to aid in major care choices.

Symptoms

First signs - Early symptoms of Juvenile Tay-Sachs include lack of coordination or clumsiness and muscle weakness such as struggling with stairs. A child may also exhibit slurred speech, swallowing difficulties and muscle cramps.

Gradual Loss of skills - Over time, children with Juvenile Tay-Sachs slowly decline, losing their ability to walk, eat on their own and communicate. Children are prone to respiratory infections and often experience recurrent bouts of pneumonia. Many have seizures.

Range of Severity - Juvenile Tay-Sachs has a broad range of severity. In most cases, the earlier the first signs are observed, the more quickly the disease will progress. For example, a child with first symptoms at age 2 will decline faster than a child with first symptoms at age 5.

Diagnosis

Tay-Sachs disease is diagnosed through a blood test to check the level of Hexosaminidase A (HexA). A follow-up DNA test may be recommended.  Any doctor can order the Tay-Sachs HexA blood test. Often, diagnosis is made by a neurologist or geneticist.

Diagnosis can also be made by a neurologist or geneticists and the completion of a metabolic evaluation.

Juvenile Tay-Sachs does not always exhibit the cherry-red spot, which can make the road to diagnosis long and challenging. Unfortunately many healthcare providers are not aware of the rare juvenile forms of these diseases and dismiss the initial diagnosis due to the age of the child. 

Management

There is no treatment or cure for Tay-Sachs disease but there are ways to manage symptoms. These range from life-extending interventions like a feeding tube to comfort measures like massage to promote relaxation. Each new diagnosis of Tay-Sachs is a unique journey.

Progressive loss of ambulatory skills followed by respiratory health and seizure management are the main symptom management issues in Juvenile Tay-Sachs. Recommendations for managing the symptoms appear in Find Support.

Newly diagnosed families should read Finding Your Philosophy of Care, available through NTSAD. It will help parents develop a care plan and care goals to aid in major care choices.

Symptoms

First signs - Early symptoms of Late Onset Tay-Sachs (LOTS) include clumsiness and muscle weakness in the legs. Once diagnosed, adults often reflect back to their childhood and realize they experienced symptoms much earlier such as not being athletic, speech difficulties and/or a stutter as a child or teenager.

Mental health symptoms may present first which can lead to an especially long road to diagnosis. About 40% of affected adults experience mental health symptoms such as bi-polar or psychotic episodes.

Gradual Loss of skills - Over time adults with Late Onset Tay-Sachs slowly decline. Adults frequently require more mobility assistance, i.e. cane to walker to wheelchair. Many experience speech and swallowing difficulties but few require a feeding tube.

Long Road to Diagnosis

Late Onset Tay-Sachs may be hard to diagnose. Some adults go five or more years before learning their true diagnosis. In some cases it may be misdiagnosed as Multiple Sclerosis or ALS.

Adults affected by the adult form of Tay-Sachs do not exhibit the tell-tale cherry-red spot, which can contribute to a challenging and long road to diagnosis. Unfortunately many healthcare providers are not aware of the rare adult forms of these diseases and dismiss the initial diagnosis due to the age of the patient.

Adults that display mental health symptoms before physical symptoms often experience the longest road to diagnosis.

Tay-Sachs disease is diagnosed through a blood test to check the level of Hexosaminidase A (HexA). A follow-up DNA test may be recommended.  Any doctor can order the Tay-Sachs HexA blood test. Often, a diagnosis is confirmed by a neurologist and/or geneticist, and after the completion of a metabolic evaluation.

Many affected adults express mixed emotions when finally receiving their diagnosis. After years of not knowing the cause of their progressive symptoms, they may experience a certain amount of relief when an accurate diagnosis is determined. At the same time, Tay-Sachs is a difficult diagnosis to receive and there can be a sense of regret and frustration.

Living with Late Onset Tay-Sachs

There is no treatment or cure for Tay-Sachs disease but there are ways to manage.

Mobility, speech and mental health are the primary symptom management issues of Late Onset Tay-Sachs. These symptoms frequently lead to other challenges related to employment, housing and communication. Click here to learn more about living with the disease.

Late Onset Tay-Sachs is a challenging and debilitating disorder but doesn't always shorten life span like the childhood forms of Tay-Sachs. 

Read the "Topic of the Week" featuring the stories of two patients with Late Onset Tay-Sachs here.

 

Explore More:

 Research - the latest in Late Onset research  

 Support - symptom management, where and how to find help, and how to cope. 

 Causes - the missing HexA enzyme

 History of Tay-Sachs Disease - named for Warren Tay and Bernard Sachs

Tay-Sachs Causes

It's about a missing enzyme.

Tay-Sachs disease is caused by the absence or significantly reduced level of a vital enzyme called beta-hexosaminidase. It is the Hexosaminidase A (HEXA) gene in the DNA that provides instructions for making this enzyme. Without the correct amount of the HexA enzyme, a fatty substance or lipid called GM2 ganglioside accumulates abnormally in cells, especially in the nerve cells of the brain. This ongoing accumulation, also called "substrate", causes progressive damage to the cells.

Infantile Tay-Sachs is typically the absence of the HexA enzyme. This differs from the Juvenile and Late Onset forms of Tay-Sachs when the mutations allow the HexA enzyme to function a little bit. Just a small increase in HexA activity is enough to delay the onset and slow the progression of symptoms.

Inheritance

Tay-Sachs is an autosomal recessive genetic disorder. Autosomal means it affects males and females equally and recessive means both parents must be a carrier for the children to be at risk. If both parents are carriers, there is a 25% chance with each pregnancy that the child will be affected. Carriers of recessive diseases do not experience any adverse health effects. ANYONE can be a carrier of Tay-Sachs but French Canadians, Louisiana Cajuns and Ashkenazi Jews are at high risk with an carrier rate of 1/27. Some data suggests people of British Isle and Irish descent are at increased risk between 1/50 to 1/150. The Tay-Sachs gene occurs in the general population at a rate of 1/250.

Tay-Sachs "breeds true" in a family. If one child is diagnosed with Infantile Tay-Sachs, the other children are only at risk for the infantile form. One set of parents could not have children with both the infantile and juvenile forms of the disease.

Gene Location

The gene that causes Tay-Sachs is located on chromosome 15, specifically 15q23-q24.

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