Summary:Purpose: To assess the long-term evolution of Unverricht-Lundborg disease (ULD), especially concerning myoclonus, seizures, and EEG characteristics.Methods: We retrospectively evaluated 20 patients (six women, 14 men; mean age, 37.9 years; range, 26-53 years) with ULD who had been closely followed up since the onset of the disease (mean age, 12.3 years; range, 6-17 years) for an average of 25.6 years (range, 13-41 years). ULD was confirmed by genetic tests in all. We used simplified myoclonus and seizure rating scales.

Information concerning the distribution of different genetic causes of PMEs may provide a framework for an updated diagnostic workup. Phenotypes of the patients with PME of undetermined cause varied widely. The presence of separate clusters suggests that novel forms of PME are yet to be clinically and genetically characterized.

Summary:Purpose: Disabling myoclonus is the main symptom in long-standing Unverricht-Lundborg disease (ULD), and levetiracetam (LEV) appears to be an effective anticonvulsant with promising short-term antimyoclonic properties.Methods: LEV was prescribed to 13 patients with ULD. We retrospectively analyzed the efficacy of LEV on seizure frequency and on myoclonus, by using a simplified myoclonus rating score, and compared the patients' status before LEV and at the last follow-up. They were two women and 11 men, aged 14 to 52 years (mean, 36.5 years), with a disease duration of 4 to 40 years (mean, 24.3 years). LEV was given at 2,000 to 4,000 mg/d for 0.5 to 26 months (mean, 13.8 months). Results:One patient stopped LEV within 2 weeks because of side effects and lack of efficacy. None of the other 12 patients reported side effects. The average myoclonus score significantly changed from 3.1 to 2.4 (p = 0.01), but only eight had a measurable improvement.Conclusions: The best effects were noted in the younger patients. In patients previously treated with high-dose piracetam (PIR), discontinuation of PIR was not always well tolerated, and a combination of PIR at lower doses and LEV appeared to be a practical solution. LEV should probably be considered as a major treatment option early in the course of ULD.

Summary Purpose:  Mutations of the SCARB2 gene cause action myoclonus renal failure syndrome (AMRF), a rare condition that combines progressive myoclonus epilepsy (PME) with severe renal dysfunction. We describe the clinical and neurophysiologic features of PME associated with SCARB2 mutations without renal impairment. Methods:  Clinical and neurophysiologic investigations, including wakefulness and sleep electroencephalography (EEG), polygraphic recording (with jerk‐locked back‐averaging and analysis of the EEG–EMG (electromyography) relationship by coherence spectra and phase calculation), multimodal evoked potentials, and electromyography were performed on five Italian patients with SCARB2 mutations. Key Findings:  The main clinical features were adolescent–young adulthood onset, progressive action myoclonus, ataxia, absence of cognitive deterioration and, in most cases, epilepsy. The severity of the epilepsy could vary from uncontrolled seizures and status epilepticus in patients with adolescent onset to absent or rare seizures in patients with adult onset. Relevant neurophysiologic findings were a pronounced photosensitivity and massive action myoclonus associated with rhythmic myoclonic jerks at a frequency of 12–20 Hz, clinically resembling a postural tremor. The cortical origin of rhythmic myoclonus was demonstrated mainly by coherence and phase analysis of EEG–EMG signals indicating a significant EEG–EMG coupling and a direct corticospinal transfer. Significance:  Our patients with SCARB2 mutations showed the clinical and neurophysiologic phenotype of PME, in which epilepsy could be extremely severe, extending the spectrum reported in the typical AMRF syndrome. Patients with PME of unknown origin of adolescent or young adult onset, with these neurophysiologic features, should be tested for SCARB2 mutations, even in the absence of renal impairment.

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