Inclusion Criteria:  Patients genetically confirmed 5q SMA including types I, II and III, who are planning to initiate treatment with SPINRAZA® (nusinersen) as part of their clinical care plan. Non-5q SMA patients undergoing clinical standard lumbar puncture Non-SMA subjects including Asymptomatic carriers of SMA, relatives of SMA patients and carriers, and patients undergoing clinical standard lumbar puncture Participants or Parent(s)/legal guardian(s) willing and able to complete the informed consent process  Exclusion Criteria:  Contraindication for lumbar puncture Inability to access intrathecal space for nusinersen injection