Pediatric Movement Disorders of Unknown Etiology in Vietnam (VPeMD)

Phenotypic and Genotypic Characterization of Pediatric Movement Disorders of Unknown Etiology in Vietnam

This observational patient registry aims to describe the clinical phenotypes and genetic findings of Vietnamese children with movement disorders of unknown etiology. Eligible participants are children with clinically confirmed movement disorders after evaluation by pediatric neurology specialists and after exclusion of clear acquired causes.

The study will collect clinical data, neurological examination findings, available laboratory and imaging results, and video recordings of abnormal movements when consent is provided. Blood samples will be collected for whole-exome sequencing and related genetic analysis. Genetic variants will be classified according to accepted clinical genetics standards and compared with the patients' clinical phenotypes.

The study is expected to improve understanding of the phenotypic and genotypic spectrum of pediatric movement disorders in Vietnam, support genetic counseling, and evaluate how genetic results may influence diagnosis, follow-up, prognosis, and treatment planning.

Movement disorders in children represent a heterogeneous group of neurological conditions that include dystonia, chorea, ataxia, myoclonus, tremor, tics, parkinsonism, and mixed movement disorders. The underlying causes are highly diverse and include genetic, metabolic, neurodegenerative, structural, immune-mediated, and acquired disorders. However, a substantial proportion of pediatric patients remain without a definitive diagnosis after standard clinical evaluation and routine investigations.

Recent advances in next-generation sequencing technologies, particularly whole-exome sequencing, have significantly improved the diagnostic yield in pediatric movement disorders and have contributed to the identification of novel disease-causing genes and genotype-phenotype correlations. Nevertheless, data regarding the clinical and genetic spectrum of pediatric movement disorders in Vietnam remain limited.

The VPeMD registry is a prospective observational patient registry designed to collect standardized clinical and genetic data from Vietnamese children with movement disorders of unknown etiology. Participants will undergo detailed clinical evaluation by pediatric neurology specialists, including assessment of movement phenomenology, neurological findings, developmental history, family history, neuroimaging findings, laboratory investigations, and treatment history.

Biological samples will be collected for genetic analysis, including whole-exome sequencing and additional molecular investigations when appropriate. Genetic variants will be interpreted according to internationally accepted standards and correlated with clinical manifestations.

The study aims to characterize the phenotypic and genotypic spectrum of pediatric movement disorders in Vietnam, evaluate diagnostic yield of genetic testing, identify genotype-phenotype correlations, and assess the potential impact of genetic diagnosis on patient management, prognosis, genetic counseling, and future therapeutic strategies.

Inclusion Criteria:

• Children younger than 18 years old.
• Patients with clinically confirmed movement disorders based on direct examination and/or video review by at least two pediatric neurology specialists.
• Patients with movement disorders of unknown etiology after appropriate neurological evaluation and exclusion of clear acquired causes.
• Patients evaluated or treated at University Medical Center Ho Chi Minh City or Children's Hospital 1 during the study period.
• Patients and/or legal guardians who provide written informed consent for study participation and genetic testing.

Exclusion Criteria:

• Patients with isolated or transient primary tic disorders.
• Patients with a confirmed acquired cause of movement disorder.
• Patients or legal guardians who decline participation or withdraw from the study.
• Patients with insufficient clinical information or unavailable biological samples for genetic analysis.