spinal muscular atrophy

Spinal muscular atrophy is a motor neuron disease that primarily affects the muscles, leading to progressive weakness and muscle wasting. It results from the degeneration and loss of lower motor neurons in the spinal cord and brain stem, which impairs mobility and the ability to control the head and trunk. The condition is typically observed in infants and young children although different subtypes can have variable ages of onset. It affects approximately 1 in 8,000 to 10,000 live births, and its severity varies considerably between individuals.

Individuals with spinal muscular atrophy often experience progressive proximal muscle weakness and hypotonia, which can present as a 'floppy' appearance in severe early-onset forms. Other characteristic features include reduced or absent deep tendon reflexes and tongue fasciculations, while cognitive development remains normal. In many cases, early signs such as poor head control and difficulties with mobility prompt further evaluation. Not all individuals experience all features, and severity varies considerably.

The underlying cause of spinal muscular atrophy is linked to disruptions in the production of essential proteins necessary for motor neuron survival. Although a specific genetic alteration is frequently involved, the precise genetic basis is not explicitly defined in the available data and remains under investigation. In a small percentage of cases, approximately 2% arise from genetic changes that are new, meaning they are not inherited from either parent, which influences recurrence risk for families.

Management of spinal muscular atrophy begins with foundational therapies that support respiratory function, nutritional status, and physical abilities. Foundational care includes respiratory support using non-invasive ventilation, nutritional management to address feeding difficulties, physical therapy to maintain muscle function and prevent contractures, and surgical intervention for scoliosis if required. In addition to these supportive measures, targeted therapies play an important role. Currently, FDA-approved treatments include SPINRAZA (nusinersen) and EVRYSDI (risdiplam), with Zolgensma also available as an FDA-approved gene therapy for eligible patients. A multidisciplinary team including neurologists, pulmonologists, orthopedic surgeons, physical therapists, respiratory therapists, geneticists, and genetic counselors collaborates to provide individualized care. Patients should discuss treatment options with their healthcare team to determine the most appropriate approach for their situation.

The outlook for individuals with spinal muscular atrophy varies widely, with the disease course ranging from gradual progression to periods of relative stability. With current standards of care, many individuals experience improved quality of life and extended survival compared to historical outcomes. Outcomes described in medical literature continue to evolve as standards of care improve, and regular monitoring is essential to address emerging complications early. Families are encouraged to connect with genetic counselors, neurologists, and specialized care centers to better understand the condition and explore ongoing support resources.

Spinal muscular atrophy remains an active area of research, with numerous clinical trials currently underway to explore combination therapies, novel gene therapy approaches, muscle-directed interventions, and neuroprotective strategies. Individuals interested in learning more about ongoing studies or considering participation in clinical trials are encouraged to search ClinicalTrials.gov or consult their care team regarding eligibility.