When you think of genetic disorders, what do you think of? Probably disorders like down syndrome, sickle cell anemia, cystic fibrosis, etc., but have you ever heard of Tay-Sachs disease?

Introduction

Tay-Sachs disease is a relatively rare genetic disorder where it is passed down from parents to offspring. According to the Mayo Clinic, Tay-Sachs disease occurs when there is an absence of an enzyme, Hex A(Beta-Hexosaminidase A), which helps with breaking down fatty substances called gangliosides [1]. This accumulation of gangliosides results in build up of toxic levels in the brain and spinal cord and affect the function of nerve cells.

Figure 1: All patients with Tay-Sachs disease have a cherry-red spot, easily observable by a physician using an ophthalmoscope, in the back of their eyes.Tay-Sachs Disease

Treatments

As of today, there has been no cure for Tay-Sachs disease nor has there been proven treatments to slow it down. However, there are treatments like anti-seizure medications, antibiotics for infection, and different types of therapy ranging from both physical and mental, that have been developed to manage symptoms that come with Tay-Sachs, those being seizures, vision and hearing loss, paralysis, etc. [1].

Diagnosis and Survival

Diagnostic tests, including blood and genetic tests, can identify Tay-Sachs disease. Despite these diagnostic advancements, due to the limited treatment options available, many diagnosed individuals typically survive for only 3 to 4 years.

Population Risk Factors

In many studies it has been found that the gene change that causes Tay-Sachs is found more often in certain groups of people. These being Ashkenazi Jews, certain French Canadian communities in Quebec, Cajun communities of Louisiana, and old order Amish communities in Pennsylvania [1].

Figure 2: Hex A The Hexa gene is the effected chromosome in the Tay-Sachs disease

Genetic Mutation and Its Impact

Tay-Sachs disease arises from a flaw in the gene coding for Hex A. This enzyme, situated on the 15th chromosome, breaks down gangliosides. A mutation in the Hex A gene, involving base nucleotide insertion or deletion, leads to its malfunction. While having at least one active Hex A gene prevents ganglioside accumulation, two inactive genes result in Tay-Sachs disease. Having one active gene allows the transmission of the faulty gene to offspring.

Research

As of today, there are many ongoing research projects all dedicated to finding a cure to Tay-Sachs.

Figure 3: Enzyme replacement therapy being studied for potential cure for Tay-Sachs disease. (Source)

Enzyme Replacement Therapy

One very notable project that has been going on is scientists beginning to explore the possibility of enzyme replacement therapy to provide Hex A in people lacking it. This involves giving people purified enzymes from human, animal, or plant cells, usually intravenous infusion. This, if it works, will be able to help correct Hex A deficiencies and prevent further damage to the body. However, enzyme replacement therapy will not be able to affect neurological features as it cannot cross the blood-brain barrier [5].

Figure 4: Details and steps of a bone marrow transplantation. (Source)

Bone Marrow Transplantation

Other avenues of research include bone marrow transplantation, which has limited success in reversing or slowing central nervous system damage, and gene therapy. Gene therapy involves replacing abnormal genes with normal ones, potentially leading to the production of normal Hex A enzymes, reducing lysosomal storage, and restoring neurological development. [6].

Figure 5: Affects to neurons after gene transfer First Human Gene Therapy Trial Planned For Deadly Tay-Sachs Disease | WBUR News

Gene Therapy

Another avenue of research that is being looked at is gene therapy. This is where scientists transfer a normal gene into cells to replace an abnormal gene. Once inside the cells, the normal genes will be able to direct the production of normal Hex A enzymes. This, in theory, will be able to eliminate the lysosomal storage in the brain and possibly the resumption of normal neurological development [7].

Conclusion

Predicting the future of Tay-Sachs disease treatment is challenging. While more study and research are necessary, gene therapy holds promise. Regardless of opinions, it's evident that Tay-Sachs disease is a pressing issue that requires attention, and with ongoing efforts, our society's creativity and hard work will likely pave the way for effective solutions.

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References

1. Tay-Sachs disease - Symptoms and causes - Mayo Clinic

2. Tay-Sachs Disease

3. About Tay-Sachs Disease

4. Cost of bone marrow transplant in India

5. Transplanting for Tay-Sachs, It's a Decision to Have Hope – The Forward

6. First Human Gene Therapy Trial Planned For Deadly Tay-Sachs Disease

7. Gene Therapy.

_By: Jerry Lou_

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of Elio Academy.