Diseases traceable to a single gene defect are a special focus of research. It is estimated that 5000 kinds of disease in people are caused by single gene defects, including Huntington's disease, thalassemia, and "brittle bone disease." It is hoped that gene therapy can take the place of bone-marrow transplants and other forms of treatment used at present, massively boosting the cure rate for many diseases.
特別是單一基因缺陷的疾病，據估計，約有五千種人類的疾病包括亨丁頓舞蹈症、海洋性貧血、玻璃娃娃等等，是由單一基因變化引起的，基因治療未來可望取代現階段骨髓移植等療法，大大提高疾病的治癒率。