This episode combines two articles and discusses the importance of laboratory expertise in accurately diagnosing autoimmune neurological syndromes, particularly autoimmune encephalitis and paraneoplastic syndromes, which are often difficult to identify due to overlapping symptoms and low prevalence. The author reviews two companion studies evaluating commercially available tissue-based assays for detecting antibodies against intracellular and surface antigens. The studies reveal significant limitations in the sensitivity and specificity of these commercial tests when used as standalone screening tools, highlighting the risk of both false positives and false negatives. Ultimately, the piece emphasizes the need for multimodal testing, skilled interpretation of results, and interdisciplinary communication between clinicians and laboratory staff to ensure reliable diagnosis and improve patient outcomes.

This paper provides a comprehensive review of repeat expansion disorders, focusing on their significance in neurology. It explains how abnormal expansions of DNA repeats cause a wide range of neurological conditions, highlighting the diagnostic challenges and opportunities for management. The authors discuss the molecular characteristics of these disorders, including repeat size, location, and inheritance patterns, and detail the clinical features like anticipation and heterogeneity that can aid in diagnosis. Finally, the piece outlines the evolution and current state of genetic testing methods, emphasizing the increasing role of whole-genome sequencing and bioinformatics tools in detecting these complex genetic variations.

This paper is a comprehensive review of IgG4-related disease (IgG4-RD) as it affects the nervous system. It discusses the clinical presentation, diagnosis, and treatment of this rare inflammatory and fibrotic condition, which can impact various parts of the nervous system, including the eyes, meninges, pituitary gland, brain parenchyma, and peripheral nerves. The article highlights the importance of early recognition and a high index of clinical suspicion due to the diverse ways IgG4-RD can manifest and mimic other conditions. While elevated serum IgG4 levels can be helpful, the paper emphasizes that histological confirmation is the gold standard for diagnosis. Treatment typically involves glucocorticoids as a first-line therapy, with other immunosuppressants like rituximab also being utilized, and a treatment algorithm for nervous system involvement is provided. The text also addresses the challenges in diagnosis due to the heterogeneity of symptoms and the ongoing need for further research and refined diagnostic criteria.