As per NINDS (National Institute of Neurological Disorders and Stroke, USA), Spinal muscular atrophy (SMA) is a group of hereditary diseases that progressively destroys motor neurons—nerve cells in the brain stem and spinal cord that control essential skeletal muscle activity such as speaking, walking, breathing, and swallowing, leading to muscle weakness and atrophy. Motor neurons essentially control movement in the arms, legs, chest, face, throat, and tongue. When there are disruptions in the signals between motor neurons and muscles, the muscles gradually weaken, begin wasting away and develop twitching (called fasciculations).
What causes SMA?
The most common form of SMA is caused by defects in both copies of the survival motor neuron 1 gene (SMN1) on chromosome 5q. This gene produces the survival motor neuron (SMN) protein which maintains the health and normal function of motor neurons. Individuals with SMA have insufficient levels of the SMN protein, which leads to loss of motor neurons in the spinal cord, producing weakness and wasting of the skeletal muscles. This weakness is often more severe in the trunk and upper leg and arm muscles than in muscles of the hands and feet. Below is a picture of an SMA patient:
How is SMA inherited?
SMA is inherited in an autosomal recessive manner, meaning that the affected individual has two mutated genes, often inheriting one from each parent. Those who carry only one mutated gene are carriers of the disease without having any symptoms. Autosomal recessive diseases may affect more than one person in the same generation (siblings or cousins).
SMA is categorized in 4 categories:
1) SMA Type I: In infants usually before 6 months of age. Without any treatment, affected children never sit or stand and the vast majority usually die of respiratory failure before the age of 2 years.
2) SMA Type II: In infants from 6 to 18 months of age. They can sit without support but are unable to stand or walk unaided, and some may lose the ability to stay seated independently over time without treatment. They may have respiratory difficulties in sleep. The progression of disease is variable without treatment. Life expectancy is reduced but most individuals live into adolescence or young adulthood.
3) SMA Type III: Develop after 18 months of age. Individuals with SMA type III may be prone to respiratory infections, but with care most have a normal lifespan.
4) SMA Type IV: Develop after 21 years of age, with mild to moderate proximal muscle weakness and other symptoms. It is not considered life threatening. It is reported that Prof. Stephen Hawking too had an adult onset of SMA Type IV.
As per above categorization, SMA Type I and SMA Type II can be life threatening for babies.
SMA and India
Recently, there was a news of a Bengaluru couple seeking Rs. 16 crores via an online crowd funding platform. Their daughter who is suffering from SMA Type I disease never crossed her 2nd milestone. Given the little knowledge about SMA in India, the parents could not figure out anything until they rushed to a pediatrician who referred their daughter to a hospital with SMA diagnosis.
Such is the shortage of knowledge about SMA in India that online search engines like Google do not have relevant data and figures related to it. As per reports, SMA is one of the most frequent serious genetic disorders in children with an estimated birth prevalence of 1 in 10,000 births and a carrier frequency of 1 in 45 individuals.
All the fuss about Rs. 16 crore funding needed
Recently, NHS England approved the most expensive drug in the world, Zolgensma priced at INR 18 crores. Zolgensma, a drug manufactured by Swiss drug-maker Novartis is life saving for babies. It can enable mobility in babies and children younger than 2 years of age. In studies, Zolgensma has been reported to help babies reach milestones such as breathe without a ventilator, sit up on their own and crawl and walk after a single infusion treatment. The latest data suggested that Zolgensma can provide rapid and sustained improvement in motor function for young children with type 1 SMA and prolong their lives. As per a specialist, “The therapy is a one-time infusion that takes about an hour. Zolgensma 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 develop more normally.” However, Zolgensma has a shelf life of 14 days only and there have been reported cases of delay in customs processes which can have a life-threatening impact on the treatment of a patient.
Measures for India to take
India has always been on the fore-front of eradicating diseases and taking the bull by its horns. However, in case of SMA, little knowledge is available to the common people. As the Government has already done in the case of polio, Covid-19 and pursuing in the case of Tuberculosis, it must bring SMA under its ambit as well. Given the research available in the international drug industry, India can sign treaties with Switzerland and USA to share the results and analysis of their researches and then use the knowledge to get patents registered in India in agreement with Swiss and US companies. Such medicines can then be made available for the babies having SMA-I and SMA-II. The corpus already allocated to R&D into the field of medicine can be utilized for developing SMA drugs as well. After all, it is the babies who might become the Kalams, the Bachchans, the Modis and the Maneckshaws of tomorrow.
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