Spinal muscular atrophy (hereinafter referred to as "SMA") is a motor neuron disease, i.e. a disease of the neurons that are responsible for conscious muscle movements, such as running, head movements and swallowing. The disease occurs in approximately 1 in 6,000 births in the population, and about 1 in 40 people are carriers of the disease. SMA affects all skeletal muscles, while the so-called proximal muscles (shoulders, hips, back muscles) are often affected the most. Weakness in the lower limbs is generally larger than the arms. Swallowing muscles, neck muscles and masticatory muscles can also be affected due to the disease. Sensory perception and skin sensitivity are not affected. The patients' intellectual abilities are also not affected. Conversely, SMA patients are often observed to be unusually mentally alert and friendly.

We divide patients into 4 groups, according to the motor development they have achieved:

Type I – acute infantile form (Werdnig-Hoffmann syndrome)
The diagnosis is usually established in children before reaching the 6th month of life. Disease progression occurs in the first months of life. Spontaneous momentum is limited to a minimum. Children suffering from SMA I usually do not survive 2 years of life.

Type II – transient late infantile form (chronic type of Werdnig-Hoffmann disease)
The diagnosis of this type of atrophy is usually established before the child reaches the age of 2. These children usually learn to sit, sometimes they can even stand on their own or take the first few steps. However, they are never able to walk on their own, as the achieved level of motor development, including the ability to stand, soon declines. If people with SMA II. type secured quality care, they live an average of 30-50 years.

Type III – juvenile form (Kugelberg-Welander syndrome)
SMA III. type usually begins in preschool or school age. The disease is usually first manifested by gait disturbances caused by increasing leg muscle weakness. Gradually, the mobility of the hands also deteriorates and the strength of the trunk muscles decreases. Between 20 and 40 years of age, patients lose mobility.

Type IV – own adult form (Aran-Duchenne syndrome)
At SMA IV. type, the first symptoms of the disease usually appear only after the age of 35. The progression of the disease is often very slow.

More information you can find at: spinalnisvalovaatrofie.cz and smaci.cz