Objective

Young-onset amyotrophic lateral sclerosis (ALS) refers to ALS patients with initial symptoms earlier than 45 years, representing a novel disease pattern. We aim to summarize the clinical and genetic features of 102 young-onset ALS patients in China. Methods: Clinical information and blood samples were collected from all registered patients, and we performed next generation sequencing techniques in an ALS customized panel to detect ALS-related genes. Results: A total of 95 sporadic ALS and seven familial ALS were involved in this study. Young-onset ALS showed male prevalence and had more spinal onset. With 44 patients carrying one or more variants, mutations in SPG11, ALS2, and SETX were the most frequent, followed by FUS variants. Other prevalent genes like SOD1, TARDBP, and C9ORF72 were relatively rare in young-onset patients. Conclusions: Our study highlighted distinct clinical manifestation and genetic background in young-onset ALS patients in China. These features should be verified in further investigations in other populations.