Treatment of Spinal Muscular Atrophy (SMA) with Gene Therapy (TH)
- Context: A gene therapy costing ₹16 crore is the only shot at life for nearly 200 children with Spinal Muscular Atrophy (SMA) Type 1, a rare genetic disease.
- The current treatment options range from medicines, which increase these proteins, to replacing the faulty gene.
- Zolgensma by Novartis, the Swiss drugmaker is a revolutionary treatment, which works by supplying a healthy copy of the faulty gene, which allows nerve cells to then start producing the needed protein. That halts deterioration of the nerve cells and allows the baby to grow more normally.
Spinal Muscular Atrophy (SMA)
- SMA is a disease caused by loss of nerve cells, which carry electrical signals from the brain to the muscles.
- The protein needed for this signalling is coded by a gene for which everyone has two copies – one from the mother and the other from the father.
- A child develops this disorder only if both the copies are faulty.
- Without treatment, this disease is ultimately fatal – The disease as it progresses, makes it extremely difficult for the babies to carry out basic activities like sitting up, lifting their head or swallowing milk.
What is Gene Therapy?
- Gene therapy is when DNA is introduced into a patient to treat a genetic disease.
- The new DNA usually contains a functioning gene to correct the effects of a disease-causing mutation.
- The DNA is carefully selected to correct the effect of a mutated gene that is causing disease.
- Gene therapy may be a promising treatment option for some genetic diseases, including muscular dystrophy and cystic fibrosis.
- There are two different types of gene therapy depending on which types of cells are treated:
- Somatic gene therapy: transfer of a section of DNA to any cell of the body that doesn’t produce sperm or eggs. Effects of gene therapy will not be passed onto the patient’s children.
- Germline gene therapy: transfer of a section of DNA to cells that produce eggs or sperm. Effects of gene therapy will be passed onto the patient’s children and subsequent generations.
How is DNA transfer done?
- A section of DNA/gene containing instructions for making a useful protein is packaged within a vector, usually a virus, bacterium or plasmid.
- The vector acts as a vehicle to carry the new DNA into the cells of a patient with a genetic disease.
- Once inside the cells of the patient, the DNA/gene is expressed by the cell’s normal machinery leading to the production of the therapeutic protein and treatment of the patient’s disease.