The Dynamics of ß-Amyloid Proteoforms Accumulation in the Brain of a 5xFAD Mouse Model of Alzheimer's Disease.

Alzheimer's disease (AD) is the leading cause of dementia among the elderly. Neuropathologically, AD is characterized by the deposition of a 39- to 42-amino acid long ß-amyloid (Aß) peptide in the form of senile plaques. Several post-translational modifications (PTMs) in the N-terminal domain have been shown to increase the aggregation and cytotoxicity of Aß, and specific Aß proteoforms (e.g., Aß with isomerized D7 (isoD7-Aß)) are abundant in the senile plaques of AD patients. Animal models are indispensable tools for the study of disease pathogenesis, as well as preclinical testing. In the presented work, the accumulation dynamics of Aß proteoforms in the brain of one of the most widely used amyloid-based mouse models (the 5xFAD line) was monitored. Mass spectrometry (MS) approaches, based on ion mobility separation and the characteristic fragment ion formation, were applied. The results indicated a gradual increase in the Aß fraction of isoD7-Aß, starting from approximately 8% at 7 months to approximately 30% by 23 months of age. Other specific PTMs, in particular, pyroglutamylation, deamidation, and oxidation, as well as phosphorylation, were also monitored. The results for mice of different ages demonstrated that the accumulation of Aß proteoforms correlate with the formation of Aß deposits. Although the mouse model cannot be a complete analogue of the processes occurring in the human brain in AD, and several of the observed parameters differ significantly from human values supposedly due to the limited lifespan of the model animals, this dynamic study provides evidence on at least one of the possible mechanisms that can trigger amyloidosis in AD, i.e., the hypothesis on the relationship between the accumulation of isoD7-Aß and the progression of AD-like pathology.

Asymmetric scapuloperoneal phenotype of MATR3-related distal myopathy: case series.

Recent research has sparked a discussion on the spectrum of diseases linked to the MATR3 gene associated with amyotrophic lateral sclerosis and distal myopathy with vocal cord and pharyngeal weakness (VCPDM). To date, fewer than 50 cases of VCPDM have been reported in the literature. We aim to build upon the work of previous researchers by gathering additional information about VCPDM. In this study, we present six patients from four unrelated families affected by VCPDM. Our observations include patients exhibiting both the typical phenotype associated with MATR3-related distal myopathy and rare symptomatic manifestations of the disease. Notably, two cases presented with an asymmetric scapuloperoneal phenotype, leading in one case to an initial misdiagnosis of facioscapulohumeral muscular dystrophy.

A Unique Observation of a Patient with Vulto-van Silfhout-de Vries Syndrome.

Introduction: Vulto-van Silfhout-de Vries Syndrome (VSVS; OMIM#615828) is a rare hereditary disease associated with impaired intellectual development and speech, delayed psychomotor development, and behavioral anomalies, including autistic behavioral traits and poor eye contact. To date, 27 patients with VSVS have been reported in the literature. Materials and Methods: We describe a 23-year-old male patient with autism spectrum disorder (ASD) who was admitted to the gastroenterological hospital with signs of pseudomembranous colitis. ASD was first noted in the patient at the age of 2.5 years. Later, he developed epileptic seizures and important growth retardation. Prior to the hospitalization, chromosomal aberrations, Fragile X syndrome, and aminoacidopathies/aminoacidurias associated with ASD were excluded. Whole-genome sequencing (WGS) was prescribed to the patient at 23 years old. Results: The patient had a heterozygous carrier of "de novo" variant c.662C > T (p.S221L) in exon 4 of the DEAF1 gene. c.662C > T had not been previously described in genomic databases. According to the ACMG criteria, this missense variant was considered to be pathogenic. VSVS was diagnosed in the patient. Conclusions: The phenotype of the patient is very similar to the data presented in the world literature. However, growth retardation and cachexia, which have not been described previously in the articles, are of interest.

Psychogenic Seizure Imitating Narcolepsy.

Psychogenic or functional neurological disorders (FND) often occur in the practice of a neurologist. Diagnosis of FND usually causes significant difficulties. Among FND, psychogenic non-epileptic seizures (PNES) comprise around 40% cases. Sometimes it is necessary to differentiate PNES from narcolepsy. We describe a 55-year-old man with frequent brief and sudden sleep-like attacks in combination with nocturnal sleep disturbance. During attacks he was unresponsive, snoring but maintained posture. He resisted passive eye opening but with rolling eyes. The patient was confused on waking. In the interictal period, there were FND signs including give-way weakness of the left hand, typical functional "leg-dragging" gait, mistake in the finger-to-nose test. Video-electroencephalogram monitoring did not detect specific epileptic activity or sleep pattern during the attacks. Polysomnography showed multiple waking episodes during the night, but no typical pattern of narcolepsy was found in the multiple sleep latency test. The patient had frequent urgent hospitalizations due to different diseases and numerous invasive procedures. Six month later, the patient obtained state related disability financial benefit, after which hospitalizations in various hospitals continued, and PNES became shorter and less pronounced.