Background: Tic disorders (TDs), including Tourette syndrome, are childhood-onset neuropsychiatric disorders characterized by motor and/or vocal tics that commonly affect children’s physical and mental health. The pathogenesis of TDs may be related to abnormal neurotransmitters in the cortico-striatal-thalamo-cortical circuitry, especially dopaminergic, glutamatergic, and serotonergic neurotransmitters. The purpose of this study was to preliminarily investigate the differences in the three types of neurotransmitters in plasma and urine between children with TD and healthy children. Methods: We collected 94 samples of plasma and 69 samples of urine from 3–12-year-old Chinese Han children with TD before treatment. The plasma and urine of the same number of healthy Chinese Han children, matched for age and sex, participating in a physical examination, were collected. Ultra-performance liquid chromatography-tandem mass spectrometry was used to detect the three types of neurotransmitters in the above samples. Results: The plasma levels of norepinephrine, glutamic acid, and γ-aminobutyric acid, and the urine levels of normetanephrine and 5-hydroxyindoleacetic acid were higher in the TD children than in healthy children. The area under the curve (AUC) values of the above neurotransmitters in plasma and urine analyzed by receiver operating characteristic curve analysis were all higher than 0.6, with significant differences. Among them, the combined AUC of dopamine, norepinephrine, normetanephrine, glutamic acid, and γ-aminobutyric acid in the 8–12-year-old subgroup was 0.930, and the sensitivity and specificity for TD were 0.821 and 0.974, respectively (p = 0.000). Conclusions: There are differences in plasma and urine neurotransmitters between TD children and healthy children, which lays a foundation for further research on the pathogenesis of TD.

Objective: Anti-contactin-associated protein 2 (CASPR2)-related autoimmune encephalitis (AE) is more common in adults than in children. Clinical understanding of anti-CASPR2-antibody (Ab)-related AE, diagnosis and treatment standards are lacking in children. Therefore, this retrospective study on clinical symptoms and treatment outcomes in children with anti-CASPR2-Ab-related AE was conducted, to improve the clinical understanding of the disease, its diagnosis and treatment.Methods: This study retrospectively assessed children with anti-CASPR2-Ab-related AE from January 1, 2020, to June 30, 2022, in the Department of Neurology at Hunan Children’s Hospital. Data regarding demographics, clinical symptoms, laboratory examinations, electroencephalography (EEG), imaging, and curative were collected.Results: Thirteen patients were positive for serum anti-CASPR2-Ab (age at manifestation, 25 months to 13 years old; median, 8.1 years old; male-to-female ratio, 8/5). One patient (P1) had dual Abs, including anti-CASPR2 and anti-N-methyl-D-aspartate receptor Abs; his symptoms were more severe than those of children with anti-CASPR2 Abs alone. The clinical symptoms of the 13 patients with anti-CASPR2 Ab were movement disorders (9/13), consciousness disorders (9/13), abnormal demeanor (8/13), seizures (7/13), language disorders (6/13), fever (6/13), pain (4/13), involuntary exercise (4/13), poor diet (4/13), vomiting (3/13), sleep disorders (3/13), mood disorders (3/13), eczema/itching/redness (2/13), sweating (P8), urinary disorders (P13), and cognitive disorders (P9). No tumors were found in any patient. Additionally, EEG results of six patients were abnormal and imaging findings such as abnormal signals were found in 10 patients. Moreover, all except one patient recovered well after treatment; P1 with overlapping syndrome underwent recovery for more than 2 years. None of the patients who recovered have had a relapse.Discussion and conclusion: Anti-CASPR2-Ab-related AE has several clinical manifestations. Anti-CASPR2-Ab levels were higher in male patients than in female patients. Moreover, related tumors are relatively rare. Most patients benefit from immunotherapy and have a lower chance of recurrence in the short term. Furthermore, different from patients who had anti-CASPR2-Ab AE alone, those with overlapping syndrome had a severe and complex condition requiring lengthy treatment and rehabilitation. Additional studies are needed to evaluate the long-term prognosis of these patients.