Understanding Type 3
Spinal Muscular Atrophy (SMA)
Type 3 Spinal Muscular Atrophy (SMA), also known as Kugelberg-Welander disease, is a form of SMA that typically manifests in early childhood, often between the ages of 2 and 17 years. It is a progressive genetic disorder that affects the motor neurons, resulting in muscle weakness and motor function impairments.
Individuals with Type 3 SMA usually experience a gradual onset of symptoms. They may initially present with mild muscle weakness, difficulty with certain movements, and an unsteady gait. Over time, muscle weakness progresses, leading to limitations in mobility and physical activities. Despite the muscle weakness, individuals with Type 3 SMA can often walk independently, although they may require assistance, such as braces or mobility aids, as the condition progresses.
Type 3 SMA is caused by mutations in the survival motor neuron 1 (SMN1) gene, leading to a deficiency of the survival motor neuron (SMN) protein. The reduced levels of this protein impair the functioning of motor neurons, resulting in the progressive muscle weakness and motor impairments observed in Type 3 SMA.
Diagnosing Type 3 SMA involves clinical evaluation, genetic testing to identify mutations in the SMN1 gene, and sometimes electromyography (EMG) to assess muscle and nerve function.
The progression of Type 3 SMA can vary among individuals. Some may experience a relatively slow progression of symptoms and maintain functional independence for many years, while others may have a more rapid decline in muscle strength and mobility. Regular medical monitoring and management are important to optimize mobility and quality of life.