This book introduces different Rare Genetic Disorders (RGDs), and challenges in their diagnosis. The chapters of the book discuss the emerging research and clinical approaches for the diagnosis of rare genetic disorders. It further reviews the future of genetic therapies for the treatment of rare genetic diseases and examine the recent advancements in the field of genetic testing for the diagnosis of these diseases. The book also covers the role of variants in the genome (genetic modifiers) that alleviate (suppress) or exacerbate (enhance) the severity of the disease, resulting in the variability of phenotypic outcomes. Further, the book examines different animal models for critical understanding of disease mechanisms, and the opportunity to evaluate the effect of therapeutic compounds in pre-clinical studies. The subsequent chapters present the state-of-the-art drug discovery strategies and biological approaches for the treatment of rare genetic disorders. Towards the end, the book reviews the current challenges in the diagnosis and treatment of the patients of rare genetic disorders and future opportunities. This book is useful for clinical geneticists, molecular and biochemical geneticists, researchers working in gene therapy and genome editing.