Spinal Muscular Atrophy Type III, also commonly referred to as SMA Type III or Kugelberg-Welander disease, is a hereditary neuromuscular disorder characterized by degeneration and loss of motor neurons in the spinal cord and brainstem. This condition falls under the broader category of spinal muscular atrophy (SMA), which encompasses a group of genetic disorders affecting the control of muscle movement.
SMA Type III typically manifests later in childhood, with symptoms appearing between the ages of 2 and 17 years. The hallmark of this condition is progressive muscle weakness and atrophy, predominantly affecting the limbs, particularly the legs. However, the severity and progression of symptoms can vary significantly among affected individuals.
Common signs of SMA Type III include difficulty in sporting activities, mild gait abnormalities, frequent falls, and difficulties in performing certain motor tasks. It is important to note that intellectual and cognitive abilities are generally preserved in individuals with this condition.
SMA Type III is inherited in an autosomal recessive manner, meaning that both parents must carry a mutation in the SMN1 gene for a child to be affected. This gene is responsible for producing a protein called survival motor neuron (SMN), which is crucial for the health and proper functioning of motor neurons.
While there is currently no cure for SMA Type III, various treatments and supportive measures can help manage symptoms and improve quality of life. These may include physical therapy, assistive devices, and medications targeting symptom control. Genetic counseling is essential for affected individuals and their families to understand the risks of inheritance and to provide support and guidance.
