All about Spinal Muscular Atrophy (SMA)

Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is the combination of inherited disorders in which specific nerve cells, i.e., motor neurons present in the spinal cord, are missing. Motor neurons of anterior horn cells are essential for creating movements in the muscles as they receive nerve impulses from the brain. Then, through peripheral nerves, they transmit signals towards the effector organs (muscles) to create a response. In SMA, there is progressive and gradual muscle wasting, medically known as atrophy. Muscle weakness also occurs due to the loss of motor neurons due to some fault in the genes. Recent researches depict that the prognostic factors for the life expectancy of people suffering from spinal muscular atrophy include the age of onset and the severity of the symptoms.

Moreover, the muscle neurons’ loss usually occurs in the body’s proximal muscles, mostly in body parts such as the back, hips, and shoulders. As the proximal muscles are involved in the body’s voluntary movements like head control, walking, crawling, and sitting, their progressive weakness results in disabilities for the kids and adults. The leading cause of spinal muscular atrophy development is the mutation in the genes, which results in the inheritance of this deadly disorder to the next generations. This neuromuscular disorder’s mortality and morbidity inversely correlate with the degree of damage appearing to the respiratory muscles.

Most of the cases of spinal muscular atrophy develop in babies and newborns. Overall, almost 68% of the children die because of spinal muscular atrophy before reaching the age of one year, and almost 80% die before reaching their fourth birthday. The survival of infants is becoming more and more possible because of innovative equipment and technology. The improvements in nutritional and respiratory care assure the expanded life expectancy of the children.

1Spinal Muscular Atrophy Symptoms

The curvature of the spinal cord (Scoliosis)

As the research indicates, most patients who suffer from spinal muscular atrophy are children and newborns, while a small number of patients are adults. The signs and symptoms of spinal muscular atrophy usually depend on the type and severity of a person’s disorder. Sometimes, the children between the ages of six and twelve starts showing noticeable spinal muscular atrophy symptoms indicating the disorder’s severity. While on the other hand, some children having the mild type of SMA don’t show any symptom even after two years of their lives.

However, the symptoms of each type of SMA are specific to the type. Here are some of the definite symptoms of spinal muscular atrophy:

The curvature of the spinal cord (Scoliosis)

The curvature of the spine or scoliosis is one of the most common spinal muscular atrophy symptoms, and the severity of the curve depends on the type of SMA a patient has. Almost 50% of the type 3 SMA patients have scoliosis and can barely walk on their own. The patients of type 1 and type 2 SMA patients also suffer from the symptom of scoliosis. There is sideways curving and bending of the spinal cord, which leads to poor posture and causes many difficulties for the patients. The curvature of the spinal cord or medically known as scoliosis usually happens in the children before the advent of puberty and just during the days of a growth spurt. The patients with mild spinal curvature do not need additional medical help, but the daily routine works suffer from their scoliosis as they are in constant pain.

Moreover, scoliosis affects the other body organs, especially those in the abdominal cavity, as the spine tends to bend, and the organs are coming together. Most of the scoliosis cases are mild, but there is a possibility of spine deformities in severe cases. Children mostly have severe scoliosis at the growing age, and only 3% of the adults have scoliosis. As the spine tends to bend in spinal muscular atrophy patients, there is not enough space left for the lungs to function correctly, thus causing breathing problems. Patients with severe SMA tend to acquire disabilities with scoliosis progression and make life harder for them.