CD59 congenital deficiency treated with Eculizumab: one year of follow-up

*Correspondence: [e-mail].

Abstract

Case Presentation: We present the case of a female patient, healthy until 6 months old, when she presented a first episode of hypotonia and weakness in lower members that occurred 3 days after pentavalent and inactivated polio vaccination. The symptoms lasted 7 days and were followed by progressive improvement without any treatment, but she remained with distal motor deficit. Later, she presented two other episodes of muscle weakness, the first at 1 year old, that occurred 7 days after triple viral and pneumococcal vaccination, and the second at 2 years and 8 months old, after a bug bite. On both occasions, she was admitted to the hospital, diagnosed with Guillain-Barré syndrome (GBS) and treated with intravenous immunoglobulin, followed by partial improvement of the symptoms. Electroneuromyography revealed chronic motor axonal polyradiculoneuropathy. Magnetic resonance imaging of the brain and spine were normal. At 2 years and 10 months, the patient was referred to a pediatric neurology center, with suspicion of recurrent Guillain-Barré syndrome. Genetic testing was requested, and exome study revealed a new mutation in the CD59 gene, in homozygosity. This mutation was initially considered a variant of uncertain significance (VUS),but was later reclassified as pathogenic after immunophenotyping test revealed total CD59 deficiency. The patient was treated with Eculizumab (30 doses) and followed by a multidisciplinary team for over one year. She has not presented any new episodes of weakness and exhibited significant improvement of motor function since the beginning of the treatment.

Discussion: CD59 deficiency is a rare disease characterized by the presence of chronic hemolysis and, less frequently, recurrent demyelination of the peripheral nervous system, resembling GBS. The case above presented clinical phenotype, laboratory and genotype consistent with CD59 congenital deficiency, confirmed by immunophenotyping test. Previous studies in medical literature are scarce, but have demonstrated benefit in the use of Eculizumab for the prevention of new episodes of demyelination and, in some cases, improvement of the motor deficit, which is consistent with what was observed in our patient.

Final Comments: The present report demonstrated that recurrent episodes of peripheral demyelination may be associated to genetic conditions such as congenital deficiency of CD59. The genetic diagnosis allowed appropriate treatment with excellent clinical response.

 

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Publication History

Article published online:
12 May 2025