Neurodegenerative diseases are progressive disorders that involve the loss and dysfunction of neurons. Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, Huntington's disease, Frontotemporal dementia are examples of diseases. While different clinically, these disorders have a common genetic, molecular and cellular basis. This review examines the common genetic pathways, along with the interactions between genes of major neurodegenerative diseases, with a focus on the key genes, such as APOE, SNCA, MAPT, TARDBP, LRRK2 and HTT. The common pathogenic mechanisms considered to play a major role in disease progression include protein misfolding and aggregation, mitochondrial dysfunction, oxidative stress, neuroinflammation, diminished autophagy, and impaired lysosomal function, as well as synaptic degeneration. The review also emphasizes the role of systems biology strategies, such as genome-wide association studies, transcriptomics, proteomics, metabolomics, interactome analysis, and multi-omics integration, to unveiling complex molecular networks in neurodegeneration. Furthermore, the emerging biomarker strategies and therapeutic strategies targeting convergence signaling pathways including NF-κB, PI3K-Akt-mTOR, MAPK and Wnt/β-catenin are summarized. The common genetic basis and the cross-connecting molecular mechanisms of the various neurodegenerative diseases could help in the discovery of new biomarkers and pan-therapeutic targets. Further advances in molecular genetics, computational biology and precision medicine are needed to enhance early detection and the creation of effective disease-modifying treatments.