Amyotrophic lateral sclerosis (ALS), one of the most prevalent neurodegenerative disorders, is pathologically characterized by the progressive degeneration of both upper and lower motor neurons, leading to muscle weakness, paralysis, and death within 2-4 years post-diagnosis. ALS is categorized into familial ALS (FALS) and sporadic ALS, with FALS accounting for approximately 10% of ALS cases. As a genetically heterogeneous disease, ALS exhibits diverse inheritance patterns, including autosomal dominant, autosomal recessive, and X-linked transmission, and genetic factors play pivotal roles in disease pathogenesis. To date, at least 34 disease-causing loci and 32 genes for ALS have been identified. The investigations of mutant protein products and the establishment of animal models have unraveled potential pathogenic pathways, offering insights into the mechanisms of neurodegeneration in ALS. This review focuses on ALS clinical characteristics, neuropathological features, causative loci/genes, genetic susceptibility factors, animal models, and pathogenic mechanisms, with particular attention to recent advances in genetic findings and pathogenic pathways of ALS. Elucidation of the genetic basis of ALS could provide the scientific foundation for personalized treatments to address this recalcitrant disease.