SMA, or spinal muscle atrophy, is caused by a deficiency of the SMN1 protein necessary for the proper functioning of the motor neurons responsible for the work of skeletal muscles. This disease is caused by a gene mutation.
The course of the disease depends on the age at which the first symptoms of the disease appeared, as well as the level of the said protein in the body. On this basis, specialists distinguish four types of SMA. Type 1 manifests itself in the first weeks of life, usually up to the 6th month of life.This is the most severe and, unfortunately, the most common form of the disease . Types 2 and 3 are manifested in toddlers, children and adolescents. Children acquire certain skills that they gradually lose due to muscle wasting. Type 4 appears in adulthood and is mildest, but usually ends with the patient losing the ability to move independently.
SMA - a rare and dangerous disease
SMA, or spinal muscular atrophy, is a rare disease. It affects a small percentage of the population - in Poland it is about 1000 people. Statistics show thatannually this disease is detected in about 50 children.Most of them have died before the age of 2, because one of the effects of muscle wasting, which is the main symptom of the disease, is respiratory failure. In a child, the disease is usually aggressive, making it difficult not only to breathe, but also to eat, and leads to complete paralysis.
This situation is changing, all thanks to a new drug that appeared on the market a few years ago. From January 2022, it is also available in Poland as part of the drug program "Treatment of spinal muscular atrophy". All patients with SMA were included in the treatment program, without any age restrictions or the severity of the disease.
- For over a year, we have had a drug program in Poland, thanks to which patients with spinal muscular atrophy receive a preparation with nusinersen, which is designed to stimulate the SMN2 gene to produce the SMN protein - explains Prof. Maria Mazurkiewicz-Bełdzińska, neurologist, president of the Polish Society of Children's Neurologists. - Clinical trials with nusinersen show that this treatment produces surprisingly good results.Children who have been given the drug have significantly improved.Even those who are still not moving have lessdrooling, easier breathing. Patients with lighter varieties of SMA say that they can finally plan something, have stronger hands, they can hold the cup - these are things that are incredibly important for patients - adds the expert.
New treatment is success
The best effects of nusinersen treatment are when the drug is administered as early as possible, i.e. in patients with presymptomatic or very few symptoms. Therefore, specialists dealing with spinal muscular atrophy urge the Ministry of He alth to introduce mandatory screening tests for newborns for SMA.
- Neonatal screening will allow to identify the patient before clinical symptoms appear, and then to implement immediate treatment - says prof. Mazurkiewicz-Bełdzińska. - Such actions may prevent a child diagnosed in this way from developing SMA symptoms at all. On the other hand, the use of treatment in a patient whose disease is already in a very advanced state may stop its course, strengthen its muscle strength, but will not make the patient stand up and walk. Destroyed neurons do not rebuild.
The sense of introducing screening tests, according to Professor Mazurkiewicz-Bełdzińska, is indicated by the clinical trials of NURTURE, which were carried out on 25 young patients diagnosed in the prenatal period due to the presence of SMA in their older siblings. These children in the first weeks of life received nusinersen treatment, which brought excellent results.
- Most of these patients behave completely like he althy children or almost like he althy children - explains our expert. They reach their milestones in their development just like their he althy peers, and we must remember that a type 1 SMA patient has historically never been sitting. And here we have children who often stand and walk. This is a revolution, a complete breakthrough. It is hoping thatSMA will cease to be a fatal diseasethat those patients on ventilators for spinal muscular atrophy will simply not be. The only condition for this success is the introduction of newborn screening.
Pilot screening tests
A pilot testing of newborns for SMA is to be carried out at the beginning of next year. Such a promise was made some time ago by the then Minister of He alth, Łukasz Szumowski. Unfortunately, the coronavirus pandemic may delay the pilot, which specialists fear.
- The situation related to COVID is dynamic, additionally there have been changes in the Ministry of He alth - explains Prof. Maria Mazurkiewicz-Bełdzińska, president of PTND. - We havehowever hope that the pilot will be introduced. At the moment, we are the second country in Europe in terms of the number of patients included in the nusinersen treatment program.We have approximately 650 treated patients and 700 eligible for treatment in all age groups and forms of SMA . I must emphasize that this program works really fantastic.