Abstract General Information

Title

Neuromyelitis Optica Association in Identical Twins: A Case Report and Review of Literature

Case Report

Case Presentation: Patient 01: Female, afrodescendant, 17 years old, presented cervical pain, subacute paraparesis and urinary retention. MRI showed longitudinal extensive transverse myelitis (LETM) from C3 to D7. Anti-aquaporin-4 was positive 1:80 (CBA). Intravenous methylprednisolone pulse for 5 days was initiated, followed by immunoglobulin for 5 days with clinical improvement. Azathioprine was instituted, however, due to hepatotoxicity, therapy was switched to rituximab. Patient 02: Female, afrodescendant, 20 years old, presented thoracic pain and paresthesia, followed by subacute paraparesis, a sensitive level at T4, urinary retention, and constipation. MRI showed LETM from C2 to D8. Anti-aquaporin-4 was positive 1:160 (CBA). Intravenous methylprednisolone pulse for 5 days was initiated, followed by plasmapheresis for 7 days with partial improvement. Immunosuppression with rituximab was instituted.
Discussion: Neuromyelitis Optica (NMO) is considered an autoimmune channelopathy that predominantly affects astrocytes in the central nervous system leading to secondary demyelination. The first biomarker found was the anti-aquaporin4 IgG antibody. Most cases of this disease are sporadic, yet 3% of cases are familial. The first case report of familial NMO in twins was in 1938, since then, several studies have investigated the association between NMO patients and susceptibility loci. NMO patients are 2.46 times more likely to have the DRB1*03 allelic group, especially DRB1*03:01 with positive IgG-NMO antibody. In Asians, the higher frequency was the DPB1*05:01 allele, which no association was found in Caucasians from Western Countries (France and South Brazil). Other risk loci have been shown as AQP4, CYP27B1, CYP7A1, and CD58, among others, however, confirmation is needed by independent cohorts.
Final Comments: NMO familial cases are rare, especially among twins, which highlights the importance of case reports about this topic. Additional studies are necessary for a better understanding of the risk loci, having in mind a future possibility to assess treatment responses based on genetic backgrounds.