Background <p>Spinal muscular atrophy (SMA) is a severe genetic neuromuscular disorder characterized by muscle atrophy and weakness due to motor neuron loss. It results from mutations in the SMN1 gene, leading to insufficient SMN protein, which is essential for motor neuron survival. SMA manifests in varying degrees of severity, with subtypes classified based on the age of symptom onset and motor function impairment. SMA type 1 is the most severe, with early onset and significant respiratory and motor complications, while SMA types 2 and 3 have later onset and less severe symptoms. Recent advancements, such as the approval of Nusinersen, offer new hope in altering the disease’s progression and improving motor functions, respiratory outcomes, and survival rates across SMA types.</p> Results <p>This systematic review included 10 studies. Significant improvements in motor function were observed, particularly in patients with SMA types 1, 2, and 3, as measured by scales, such as CHOP INTEND, HFMSE, and 6MWT. Respiratory function and survival outcomes were mixed, with some patients requiring ongoing ventilation support despite motor function improvements. The safety profile of Nusinersen was generally favorable, with mild to moderate adverse events such as headaches and back pain being the most common. Severe adverse events, though rare, included cases of aseptic meningitis and increased intracranial pressure, highlighting the need for careful monitoring during treatment.</p> Conclusions <p>This review confirms that Nusinersen is safe and effective for treating SMA across different types and severities. It improves motor and respiratory functions with manageable side effects. The findings support Nusinersen’s role in SMA treatment and provide valuable guidance for both clinical practice and future research. Early treatment initiation and attention to individual patient needs are emphasized to achieve the best outcomes.</p>