Allogeneic Hematopoietic Stem Cell Transplantation as a Therapeutic Approach for Hereditary Diseases

<b>Background/Objectives:</b> Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an established therapy for a range of hereditary disorders, including hemoglobinopathies, primary immunodeficiencies, and lysosomal storage diseases. Despite its long-standing use, rapid developments in donor availability, conditioning strategies, and supportive care have significantly broadened and refined its clinical application. This review combines recent evidence to clarify how these advances redefine current indications and therapeutic expectations. <b>Methods:</b> We critically analyze contemporary clinical data with a focus on elements that have undergone meaningful evolution-donor selection algorithms, conditioning intensity, graft manipulation, and post-transplant management. Comparative outcomes across major hereditary disease groups were examined to identify emerging trends in efficacy and safety. <b>Results:</b> The analysis highlights several novel shifts: expanding eligibility due to improved donor options, increasing reliance on reduced-toxicity regimens, and enhanced understanding of the mechanistic basis for hematologic, immunologic, and metabolic correction. These developments collectively improve survival and functional outcomes across diverse hereditary disorders. <b>Conclusions:</b> allo-HSCT remains a key therapeutic strategy for selected hereditary diseases, offering durable hematologic and metabolic correction. The prospective development of gene-addition and genome-editing therapies creates opportunities to complement-or in some cases replace-allo-HSCT, supporting the emergence of more personalized treatment approaches.