Side effects of the onasemnogene abeparvovec (OA), the gold standard for gene therapy of infants with SMA, are rare but potentially worrying. Italian clinicians report the case of a child diagnosed at three weeks of age, treated first with nusinersen and then with OA at 5.5 months of age.
- The patient presented a febrile episode with vomiting and loss of appetite shortly after the injection of OA.
- The CPK level rose from 369 international units per litre to a transient peak of 1,755 IU/l on the fourth day, with the child’s condition improving in the meantime.
- The authors describe this episode as myositis, although some signs were also suggestive of a minimal thrombotic microangiopathy.
Acute Benign Myositis Following Onasemnogene Abeparvovec Therapy in Type 1 Spinal Muscular Atrophy. Dosi C, Tozzo A, Masson R. Pediatr Neurol. 2022 Jun;131:23-24.