The disease affects people of different ages, however, in more than 90% of cases, symptoms appear in infancy or early childhood. In Poland, one in 7,000 newborns has a genetic defect underlying SMA and at some point in their lives will develop symptoms of the disease.
SMA is the result of a genetic defect – mutation in the SMN1 gene. This person receives this mutation from both parents, who are usually unaware of having it.
By the time modern methods of respiratory care and pharmacological treatment were introduced, SMA was the most common genetic cause of death for children up to two years of age.
SMA has no effect on cognitive and intellectual development. Children with SMA are mostly highly intelligent, cheerful and they enjoy life.
Traditionally, the disease is divided into four types or forms depending on the stage of motor development at which it was observed, that is, directly from age. In infants and young children, the first symptoms usually appear suddenly, and the state of health worsens week by week. If treatment is not introduced immediately, children stop in physical development, do not acquire the ability to sit independently, gradually lose the ability of breathing and swallowing independently exposing themselves to severe infections. They require 24/7 care. It is the most severe, infantic form of SMA, the so-called. SMA type 1.
If it appears in older children or later, the disease proceeds more leniently. At the time of the first symptoms, children are already able to sit (SMA type 2) or even walk (SMA type 3), or even the disease appears in adulthood (SMA type 4). However, SMA always causes progressive paresis, muscle contractions and impairs the ability to move independently. Almost all SMA patients are wheelchair-bound.
Proper medical care, especially physiotherapy, can significantly slow down the progression of the disease. Modern drug treatment not only stops the progression of the disease but brings a measurable improvement in health. Treatment introduced before the onset of the first symptoms of the disease, e.g. shortly after birth, is able to completely prevent the disease, and therefore it is most beneficial to conduct screening of newborns for the presymptomatic start of treatment.
SMA develops due to a genetic defect (mutation) in the gene responsible for SMN coding – a protein necessary for the functioning of motor neurons. One in 35 people has a mutation in Poland. If both parents are carriers of this defect, there is a 25% risk that their child will have an SMA.
The prevalence of spinal muscle atrophy in Poland is not exactly known. It is estimated that there are currently around 800-1000 SMA patients living in our country, and every year about 40 children with spinal muscular atrophy are born in Poland, including about 30 with its heaviest Type 1 form.