This paper provides a comprehensive review of repeat expansion disorders, focusing on their significance in neurology. It explains how abnormal expansions of DNA repeats cause a wide range of neurological conditions, highlighting the diagnostic challenges and opportunities for management. The authors discuss the molecular characteristics of these disorders, including repeat size, location, and inheritance patterns, and detail the clinical features like anticipation and heterogeneity that can aid in diagnosis. Finally, the piece outlines the evolution and current state of genetic testing methods, emphasizing the increasing role of whole-genome sequencing and bioinformatics tools in detecting these complex genetic variations.