Spinal muscular atrophies (SMA)

Spinal muscular atrophies (SMA) are a group of congenital clinically and genetically very different diseases characterized by progressive weakness and muscular atrophy caused by the death of the 2nd motor neuron in the spinal cord and brainstem.

The most common and best known form is proximal chromosome 5q-associated spinal muscle atrophy (SMA5q), which is caused by autosomal recessive mutation in the survival motor neuron gene (SMN1). The SMA5q and is differentiated into 4 phenotypes based on the onset and achievement of motor milestones. Less than 5% of childhood SMA cases are not caused by deletion of the SMN1 gene. Additional neurological and non-neurological symptoms may occur.

Although SMA is significantly more common in children, adult SMAs occur with proximal and distal distribution patterns depending on the gene involved.

For chromosome 5q-associated spinal muscular atrophy, antisense oligonucleotide therapy was already approved in 2017 (Spinraza). Further therapeutic options are gene replacement therapy (Zolgensma), which has been conditionally approved by the European Medicines Agency (EMA) since 2020, and the splice modifier Risdiplam (Evrysdi, approved in the US since 2020, in Europe at an advanced stage of approval).

Patients with SMA and suspected SMA can contact our motor neuron outpatient clinic for diagnostics, therapy and medical care.