Background: Recent efforts have described an immunogenic component to the pathobiology of Alzheimer’s disease (AD) and Parkinson’s disease (PD). However, current methods of studying fluid autoantibodies, such as enzyme-linked immunosorbent assays and immunohistochemistry, are hypothesis-driven and not optimal for discovering new autoantibody biomarkers by proteome-wide screening. Recently, we developed a general mass spectrometry-based approach to identify tissue-specific autoantibodies in serum, at a proteome-wide level. In this study, we adapted the method to explore novel autoantibody biomarkers in the cerebrospinal fluid (CSF) of AD and PD patients. Methods: CSF samples were obtained from 10 headache control individuals, 10 AD patients and 10 PD patients. Antibodies present in the CSF were isolated by immobilization to protein-G magnetic beads. These antibodies were incubated with a brain tissue extract, prepared from frontal cortex, pons, cerebellum and brain stem. Protein antigens captured by the protein-G magnetic bead-bound antibodies were digested with trypsin and analyzed using mass spectrometry. Autoantibody candidates were selected by 1) detection in one or less individuals of the control group and 2) identification in at least half of the patient groups. Results: There were 16 putative autoantibody biomarkers selected from the AD group. Glia-derived nexin autoantibody was detected in eight of ten AD patients and was absent in the control group. Other AD pathology-related targets were also identified, such as actin-interaction protein, quinone oxidoreductase, sushi repeat-containing protein, metalloproteinase inhibitor 2, IP3 receptor 1 and sarcoplasmic/endoplasmic reticulum calcium ATPase 2. An additional eleven autoantibody targets were also identified in the present experiment, although their link to AD is not clear. No autoantibodies in the PD group satisfied our selection criteria. Conclusion: Our unbiased mass spectrometry method was able to detect new putative CSF autoantibody biomarkers of AD. Further investigation into the involvement of humoral autoimmunity in AD and PD pathobiology may be warranted.

The DEAD/DExD/H-box RNA helicases are a group of RNA-binding proteins involved in the metabolism of mRNAs. They coordinate gene expression programs and play a role in cellular signaling, fate, and survival. We describe a case of a 36-year-old female with neuromuscular disease, sensorineural hearing loss, retinitis pigmentosa, and primary ovarian insufficiency harboring a heterozygous de novo missense pathogenic variant in the DEAH-box helicase 16 (DHX16) gene. This is the first case exhibiting a high intellectual level and the highest survival outcome so far. Eight previous cases of DHX16 disease-causing variant carriers have been described with common features, including muscle weakness with hypotonia, myopathy or peripheral neuropathy, sensorineural hearing loss, abnormal retinal findings, and infantile spasms or epilepsy. Increasing evidence associates RNA-binding proteins, including the DEAD/DExD/H-box helicase family genes, with neuropsychiatric or neurodevelopmental disorders. DHX16 genetic analysis should be considered early when diagnosing a child or young adult with muscular disease, severe hearing loss, and ocular anomalies.

Background and objectives: Movement disorders are an underrecognized phenomenon in Myelin Oligodendrocyte Glycoprotein-Associated Disease (MOGAD). The aim of this paper was to summarize all movement disorders previously described in MOGAD. Materials and Methods: We conducted a systematic literature search in PubMed, Web of Science, and Scopus in English, focusing on patients with MOGAD exhibiting a movement disorder, i.e., ataxia, tremor, dystonia, parkinsonism, chorea, athetosis, myoclonus, ballism, tics, stereotypies, dyskinesia. Results: We included 58 studies, with a total of 91 patients with MOGAD and a movement disorder (45.6% male, 54.4% female). Movement disorders had a mean latency of 2.1 years (±6.9, 0–42) after MOGAD onset; however, they could be the presenting feature (in approximately 70% of cases), especially in pediatric patients. Cerebellar ataxia was the most common movement disorder, occurring in 77 patients (84.6%). Tremor, postural and/or kinetic, was the second most common movement disorder (15%). Dystonia was reported in 8.8%, presenting as cervical, or limb dystonia or stereotyped dystonic episodes. Myoclonus and hypokinetic movement disorders were rare. Subcortical (in 60%), brainstem and cerebellar lesions (in 50% respectively) were the most common imaging findings. The most common accompanying symptoms were encephalopathy, fever and headache. Approximately half of the patients made a full recovery, and the other half showed a significant improvement in the movement disorder after immunomodulatory treatment, most commonly steroids. Conclusions: The new onset of a movement disorder, especially ataxia, in a young patient should prompt the search for MOGAD or can indicate a relapse in patients with an established diagnosis.

Background and Objectives: KBG syndrome is a rare autosomal developmental disorder caused by pathogenic variants of the ANKRD11 gene. This scoping review aimed to explore all current literature data regarding clinical and electroencephalographic features of patients with KBG syndrome and epilepsy. Materials and Methods: We conducted a literature review of previously published cases of patients with KBG syndrome and epilepsy in PubMed, Scopus, and Web of Science databases in English, focusing on seizure semiology and electroencephalographic features. Results: Fifty‐four studies were included in the review, including 233 patients with KBG syndrome and epilepsy. Most children with KBG syndrome and epilepsy (89.7%) had developmental delay and intellectual disability. The most common neurological symptoms were hypotonia (30.7%), sleep disturbances (20%), ataxia (18.7%), migraine (8.3%), and stereotypies (6.7%) ( N = 75, available data on neurological symptoms). The median age of developing seizures was 4 years (range 1 month–51 years). Patients with KBG syndrome had most commonly generalized seizures (73.9%), although focal seizures occurred in 37.9% of cases ( N = 140, available data on seizure type). Generalized tonic–clonic seizures were the most common seizure type (38.2%), followed by absences (26.6%), and focal seizures with or without preserved consciousness (21.9% and 19.1%, respectively). Interictal EEG showed focal and, less frequently, generalized discharges (24.6% vs. 15%) in the 118 patients with available EEG data. Almost 70% of patients were seizure‐free after a mean follow‐up of 9.9 years, while drug‐resistant epilepsy was reported in 22.6% of cases. Patients with focal impaired consciousness seizures had significantly lower odds of achieving seizure freedom. Conclusion: Epileptic seizures in patients with KBG syndrome are usually generalized and have an onset between infancy and mid‐teens. Common epileptological features in KBG syndrome comprise the good response to antiseizure medication and, in most cases, the remitting nature of epilepsy. Drug‐resistant epilepsy can be observed in up to one‐third of cases.