Clinical Features and Potential Etiology of Epilepsy and Nodding Syndrome in the Mahenge Area, Ulanga District

Background: Childhood epilepsy disorders are particular frequent in the area around Mahenge, southern Tanzania and recent studies have described a novel type of epilepsy with repetitive head nodding episodes and often progressive cognitive dysfunction. Despite the disease affecting thousands in Tanzania, Uganda and South Sudan, etiology and pathogenesis of the disorder termed Nodding Syndrome (NS) is still obscure as the phenotype remains imprecisely described. Epidemiological associations with Onchocerca volvulus and Mansonella spp. were noted at different African sites and remain robust even though no evidence for the presence of O. volvulus in CSF or any previous contact with the CSF was found. Hypothesis: With regard to the complex host immune reaction to O. volvulus, the investigators hypothesize that the immune response against filariae might contribute to NS and epilepsy. The investigators further assume that specific genetic traits might play a role in the pathogenesis of NS. Aims In the present study the investigators aim to examine if and how O. volvulus and/or Mansonella spp. contribute to the pathology of NS/epilepsy and therefore intend to analyze the filarial infection and the host immune response in affected children. To identify inherited traits predisposing for epilepsy, NS or specific immune responses, a genetic workup that includes whole-exome sequencing (WES) is performed. The clinical and EEG characteristics are further defined. Cognitive impairment of people with epilepsy and NS is assessed using the Wechsler Nonverbal Scale of Ability (WNV). Study design: A cross-sectional observational (groups I-III) and a case-control (groups I-V) study recruiting in total 250 patients and controls (I: people with NS, n=50; II: people with epilepsy (PWE) and onchocerciasis, n=50; III: PWE without onchocerciasis, n=50; IV: controls with onchocerciasis but otherwise healthy, n= 50; healthy controls without evidence for onchocerciasis, n= 50) is performed to