Spinal muscular atrophy (SMA) is a rare genetic disease that affects the motor neurons due to a protein deficiency as a consequence of a mutation in the SMN1 gene. When the central nervous system receives a stimulus, it produces an appropriate response to the information processed, which can be endocrine or muscular in nature, depending on the stimulus. The degradation of these important cells results in problems related to movement and muscle pain.
Depending on the symptoms that the patient presents, we can differentiate between several categories of spinal muscular atrophy.
Also known as Werdnig-Hoffmann’s disease, the symptoms appear before six months of age. The individual stops developing during the growth stages and presents great muscle weakness (hypotonia). This alteration, together with the abnormal secretion of other substances, causes great difficulty in breathing. The most striking symptom is the position of the legs (called frog legs) that appears with a generalized lack of reflexes. In addition, involuntary jerking of a muscle (fasciculation) can occur.
The symptoms appear between six and eighteen months of age. Subjects have difficulty standing and sitting up but can stay erect or seated on their own; they are not able to walk without assistance. Tremors may appear, especially when the patient extends the fingers.
It is called Kugelber-Welander disease. The symptoms appear between childhood and puberty. Patients can walk and sit on their own but can experience pain when they lean. In some cases, tremors and scoliosis (deviation of the spine) may appear together with alterations in the joints.
Also known as Kennedy’s disease. Symptoms appear during adulthood, usually at the age of 35. The patient experiences weakness of the facial muscles and serious dietary issues. Muscle atrophy extends and aggravates with the passage of time, along with a loss of sensitivity in the hands and feet. Fasciculation is also frequent and other neuropathies can develop.
As mentioned before, this disorder has a genetic origin where there is an alteration in the SMN1 gene, this means that the patient is not able to synthesize certain proteins essential for the maintenance of the motor neurons. The degeneration of these correlates to the weakness of the skeletal muscle. For this mutation to be present in the children, both parents must be carriers of the defective gene.
The tests most used to identify this pathology are:
A DNA analysis of the patient through the extraction of blood and its examination in the laboratory. This way, the gene in question is observed and identified
Electromyography and studies of nerve conduction velocity, which serve to analyze the efficacy of the electrical activity of the central nervous system.
A muscle biopsy to detect neuromuscular diseases
Other routine tests such as urinalysis to detect metabolic waste abnormalities.
To this day, no effective cure for this disease has been discovered. Within the therapeutic arsenal used, there are numerous treatments focused on alleviating the symptoms that the patient may present, among them we include medication to control spasms and analgesics that alleviate muscle pain. Physiotherapy sessions are also useful to avoid other complications. Some orthopedic devices such as a wheelchair, help the patient to better perform activities of daily life. It is also important to establish control of pulmonary ventilation and appropriate diet. In some cases, individuals must be intubated because they have difficulty swallowing.