Related Experiment Video
Updated: Nov 24, 2025
Electrophysiological Motor Unit Number Estimation MUNE Measuring Compound Muscle Action Potential CMAP in Mouse Hindlimb Muscles
Published on: September 25, 2015
Clinical features of spinal muscular atrophy (SMA) type 2
C Cancès1, C Richelme2, C Barnerias3
1AOC (Atlantique-Occitanie-Caraïbe) Reference Centre for Neuromuscular Disorders, Neuropaediatric Department, Toulouse University Hospital, Toulouse, France.
Insights
Spinal muscular atrophy (SMA) type 2, an intermediate form of SMA, presents with muscle weakness and hypotonia in infants. Standardized care and new therapies are improving quality of life and outcomes for affected children.
Area of Science:
- Neurology
- Pediatrics
- Genetics
Background:
- Infantile spinal muscular atrophy (SMA) type 2, also known as intermediate SMA, is characterized by specific developmental milestones and early clinical signs.
- Motor neuron degeneration in SMA type 2 leads to a range of functional, orthopedic, respiratory, nutritional, and psychosocial challenges.
Purpose of the Study:
- To provide an overview of infantile spinal muscular atrophy (SMA) type 2.
- To highlight the impact of standardized care and emerging therapies on patient outcomes.
Main Methods:
- Review of clinical presentation and disease progression in SMA type 2.
- Discussion of current management strategies and therapeutic advancements.
Main Results:
- Patients typically achieve normal psychomotor development until 6-8 months, followed by muscle weakness, hypotonia, and areflexia, primarily in lower limbs.
- Standardized care recommendations have enhanced patient quality of life and survival rates.
Conclusions:
- The clinical evolution of SMA type 2 is significantly influenced by the implementation of standardized care.
- Innovative therapies offer further potential to improve the long-term prognosis and clinical trajectory for individuals with SMA type 2.
Abstract:
Infantile spinal muscular atrophy (SMA) type 2 is sometimes called intermediate SMA to indicate the disease severity. Generally, psychomotor development is normal until the age of 6 to 8 months, with the acquisition of a stable sitting position. The early signs are muscle weakness, mostly affecting the lower limbs, generalized hypotonia and areflexia. The consequences of motor neuron degeneration are functional and orthopaedic, respiratory, nutritional, socio-professional, and psychological. The implementation of standardized care (i.e., standard of care recommendations) has improved the quality of life and survival outcome of patients. The emergence of innovative therapies, some of which are now available, should further improve the clinical evolution of this disease. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.
Related Concept Videos
01:28Disorders of the Skeletal Muscle
Musculoskeletal disorders
Musculoskeletal disorders involve injuries and conditions affecting the skeletal muscles and associated connective tissues. These disorders can arise from acute biomechanical stresses or chronic overuse and can occur across different age groups. Common injuries include sprains, fractures, and muscular strains, often resulting from...
01:21Satellite Stem Cells and Muscular Dystrophy
01:20Myasthenia Gravis: Overview and Treatment
These antibodies interfere with the function of the nicotinic receptors in three ways: by binding to the receptor and disrupting acetylcholine binding; by causing cross-linking of receptors which...
01:15Myasthenia Gravis: Diagnostic Tests
The edrophonium test is a diagnostic tool for myasthenia gravis. It involves...
01:26Cross-bridge Cycle
01:26Chemical Synapses
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...