Spinal Muscular Atrophy (SMA)

SMA is an autosomal recessive neuromuscular disease caused by SMN1 gene deletions or mutations leading to degeneration of anterior horn cells. Severity correlates with SMN2 copy number. Newborn screening now enables early treatment, dramatically improving outcomes.

Types & Presentation

• Type 0: prenatal onset, severe weakness, respiratory failure at birth
• Type 1 (Werdnig-Hoffmann): onset <6 months, never sit unsupported
• Type 2: onset 6–18 months, sit but never walk independently
• Type 3 (Kugelberg-Welander): onset >18 months, walk initially but may lose ability
• Type 4: adult onset, mild weakness

Diagnosis

• SMN1 gene testing (homozygous deletion/point mutation)
• SMN2 copy number informs severity
• Electromyography and CK supportive but not required
• Newborn screening identifies affected infants before symptoms

Disease-Modifying Therapies

• Nusinersen (Spinraza): antisense oligonucleotide administered intrathecally to increase SMN protein via SMN2 splicing modulation
• Onasemnogene abeparvovec (Zolgensma): AAV9 gene therapy delivering functional SMN1 (single IV infusion, weight-limited)
• Risdiplam (Evrysdi): oral SMN2 splicing modifier for infants to adults
• Choice depends on age, weight, SMN2 copies, access, and comorbidities
• Combination/sequence therapy being studied

Supportive Care

Respiratory

• Airway clearance (cough assist, suction), noninvasive ventilation, pulse oximetry
• Vaccinations (influenza, pneumococcal, RSV monoclonal)
• Monitor for sleep-disordered breathing

Orthopedic & Rehab

• Physical/occupational therapy, positioning, stretching to prevent contractures
• Orthoses, standing frames, scoliosis monitoring (spinal fusion if needed)
• Adaptive equipment (power chairs, robotic arms)

Nutrition & GI

• Swallowing assessments, gastrostomy feeding for aspiration risk
• Manage reflux, constipation
• Monitor weight to maintain dosing eligibility for therapies

Psychosocial & Transition

• Educational accommodations, assistive communication
• Mental health support, respite for caregivers

Living with SMA

• Track motor milestones, respiratory metrics, therapy dosing schedules, imaging, labs
• Plan for procedures requiring sedation/anesthesia (intrathecal access, port)
• Coordinate multidisciplinary SMA clinic visits
• Advocate for insurance coverage and clinical trial access

Complications

• Respiratory infections and failure
• Scoliosis, hip dislocation
• Joint contractures, osteoporosis
• Fatigue, limited independence

Research & Future Directions

Gene editing, combination therapy, muscle-directed treatments, and digital biomarkers are expanding options.

Experimental & Emerging Treatments

• Gene Editing (CRISPR): Direct SMN1 correction in preclinical models.
• Myostatin Inhibitors: Boost muscle mass alongside SMN therapy.
• Neuroprotective Agents: Target downstream neuromuscular junction health.
• Digital Mobility Tracking: Wearables to objectively measure therapy response.

Track SMA with Diagnoza.care

Coordinate Every Therapy Milestone – Log nusinersen/risdiplam doses, gene therapy status, respiratory support, imaging, PT/OT sessions, orthopedic procedures, nutrition plans, and equipment; capture side effects; and let the AI companion remind you of surveillance and infusions.

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Medical Disclaimer: Informational only. Work with a certified SMA center for therapy selection, dosing, and multidisciplinary management. Sources: Cure SMA, Muscular Dystrophy Association, American Academy of Neurology