Narcolepsy type 1 and Sydenham chorea - Report of 3 cases and review of the literature.

Objectives/background: Narcolepsy type 1 (NT1) is an immune-mediated disorder characterized by excessive daytime sleepiness, cataplexy, low levels of hypocretin-1 in the cerebrospinal fluid, and a strong association with the HLA DQB1*06:02 allele. There is evidence for streptococcal infections as one pathogenic factor that may lead to NT1 as part of a multifactorial pathogenesis. Elevated titers of Antistreptolysin-O antibodies and increased inflammatory activity in response to streptococci antigens have been described in patients with NT1. Sydenham chorea (SC) results from a post-streptococcal autoimmune process targeting basal ganglia neurons. Despite this common trigger, SC has been interpreted as a misdiagnosis in a few described cases of patients who were first diagnosed with SC and later with NT1. Our goal was to analyze the association between SC and NT1.
Patients/methods: We reviewed the literature and report three patients from three European sleep centers who were diagnosed with both SC and NT1 within a few months.
Results: We describe the cases of one male (age 10) and two female (age 22 and 10) patients.
Conclusions: We argue that in those cases both diagnoses are justified, unlike reports of previous cases in which SC was considered a misdiagnosis in patients with NT1. It remains, however, unclear if the conditions occur independently or if there is an overlap disorder- an SC-like subtype of narcolepsy with a particular sequence of symptoms. Further studies need to clarify the causality of the relationship and the pathophysiology of the reported rare association.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Elena S. Wenz reports a relationship with University of Bern that includes: funding grants. Ulf Kallweit reports a relationship with Bioprojet, Jazz Pharmaceuticals, Takeda Pharmaceuticals that includes: consulting or advisory and speaking and lecture fees. Rolf Fronczek reports a relationship with Takeda Pharmaceuticals, Bioprojet that includes: consulting or advisory. Rolf Fronczek reports a relationship with Jazz Pharmaceuticals that includes: funding grants. Gert Jan Lammers reports a relationship with Bioprojet, Jazz Pharmaceuticals, Takeda Pharmaceuticals, NLS Pharmaceutics that includes: consulting or advisory and speaking and lecture fees.
(Copyright © 2023. Published by Elsevier B.V.)