Association of severe myoclonic epilepsy of infancy (SMEI) with probable autoimmune lymphoproliferative syndrome-variant

Abstract

The paper reported on a case of severe myoclonic epilepsy of infancy (SMEI) associated with a probable autoimmune lymphoproliferative syndrome variant (Dianzani autoimmune lymphoproliferative disease) (DALD). A male patient with typical features of SMEI and a SCN1A gene variant presented in the first year of life with multiple lymph nodes, palpable liver at 2 cm from the costal margin, neutropenia, dysgammaglobulinemia, relative and sometimes absolute lymphocytosis. Subsequently the patient presented with constantly raised IgA in serum and positive antinuclear and thyroid antimicrosomal antibodies. The diagnosis of probable autoimmune lymphoproliferative syndrome was made; arthritis, skin and throat blisters, which appeared subsequently led to the diagnosis of linear IgA disease. On the basis of these unique associations, the Authors hypothesized that autoimmunity may be partly responsible of the severe epileptic symptomatology, perhaps mediated by autoantibodies against sodium channels or by accompanying cytotoxic T-lymphocytes. Corticosteroid treatment ameliorated the epilepsy and laboratory tests. Future studies will be necessary to evaluate the relevance of autoimmunity in SMEI.

Keywords

• severe myoclonic epilepsy of infancy
• autoimmune lymphoproliferative syndrome
• voltage-gated sodium channels
• linear IgA disease