See Morris and Weil (doi: ) for a scientific commentary on this article. In a prospective multicentre study involving 1280 patients with idiopathic RBD, Postuma et al. show that approximately 6% of patients each year (>73.5% over 12 years) convert to full neurodegenerative disease. They test the predictive power of 21 prodromal markers of neurodegeneration, providing a template for planning neuroprotective trials.

Progressive supranuclear palsy (PSP) is a movement disorder with prominent tau neuropathology. Brain diseases with abnormal tau deposits are called tauopathies, the most common being Alzheimer’s disease. Environmental causes of tauopathies include repetitive head trauma associated with some sports. To identify common genetic variation contributing to risk for tauopathies, we carried out a genome-wide association study of 1,114 PSP cases and 3,247 controls (Stage 1) followed up by a second stage where 1,051 cases and 3,560 controls were genotyped for Stage 1 SNPs that yielded P ≤ 10−3. We found significant novel signals (P < 5 × 10−8) associated with PSP risk at STX6, EIF2AK3, and MOBP. We confirmed two independent variants in MAPT affecting risk for PSP, one of which influences MAPT brain expression. The genes implicated encode proteins for vesicle-membrane fusion at the Golgi-endosomal interface, for the endoplasmic reticulum unfolded protein response, and for a myelin structural component.

Summary Background Autoimmunity may be involved in sleep and neurodegenerative disorders. We aimed to describe a neurological syndrome with prominent sleep dysfunction and antibodies to a previously unknown neuronal antigen. Methods In this observational study, clinical and video-polysomnography (V- PSG) investigations identified a novel sleep disorder in three patients referred to the Sleep Unit of Hospital Clinic University of Barcelona for abnormal sleep behaviors and obstructive sleep apnea(OSA). They had antibodies against a neuronal surface antigen also present in five additional patients referred to our laboratory for antibody studies. These five patients had been evaluated with PSG and in two, the study was done or reviewed in our Sleep Unit. Two patients underwent postmortem brain examination. Immunoprecipitation and mass spectrometry were used to characterize the antigen and to develop a diagnostic test. Serum or CSF from 285 patients with neurodegenerative, sleep, or autoimmune disorders served as controls. Findings All eight patients (five women; range: 52–76 years, median 59) had abnormal sleep movements and behaviors and OSA confirmed by PSG. Six patients had a chronic evolution (range 2–12 years, median 5.5); in four the sleep disorder was the initial and most prominent feature, and in two it was preceded by gait instability, and followed by dysarthria, dysphagia, ataxia, or chorea. Two patients had a rapid evolution with disequilibrium, dysarthria, dysphagia, and central hypoventilation, and died two and six months after symptom onset. In 5/5 patients, the V-PSG reviewed in our Unit disclosed OSA, stridor, and abnormal sleep architecture with undifferentiated NREM sleep or poorly structured stage N2 with simple movements and finalistic behaviors, normalization of NREM sleep by the end of the night, and REM sleep behavior disorder. Four/4 patients carried the HLA-DRB1*1001 and HLA-DQB1*0501 alleles. All patients had antibodies (mainly IgG4) against IgLON5, member of a family of neuronal cell adhesion molecules. Only 1/285 controls (with progressive supranuclear palsy) had IgLON5 antibodies. Neuropathology showed neuronal loss and extensive deposits of hyperphosphorylated tau mainly involving the tegmentum of the brainstem and hypothalamus. Interpretation IgLON5-antibodies identify a unique NREM and REM parasomnia with sleep breathing dysfunction and pathological features suggesting a tauopathy. Funding Fondo de Investigaciones Sanitarias. Centros de Investigación Biomédica en Red de enfermedades neurodegenerativas (CIBERNED) and Respiratorias (CIBERES), Ministerio de Economía y Competitividad, Fundació la Marató TV3 and the National Institutes of Health.