Friedreich Ataxia: An (Almost) 30-Year History After Gene Discovery.

Abstract

In the late 1800s, Nikolaus Friedreich first described "degenerative atrophy of the posterior columns of the spinal cord," noting its connection to progressive ataxia, sensory loss, and muscle weakness, now recognized as Friedreich ataxia (FRDA). Renewed interest in the disease in the 1970s and 80s by the Quebec Cooperative Group and by Anita Harding led to the development of clinical diagnostic criteria and insights into associated biochemical abnormalities, although the primary defect remained unknown. In 1988, Susan Chamberlain mapped FRDA's location on chromosome 9. In the early 90s, collaborative research, including work by the author's team, identified a gene, later named FXN, containing an expanded GAA repeat-confirming it as the FRDA mutation. This discovery established a diagnostic foundation for FRDA, advancing genetic testing and opening new research avenues. These new areas of study included the characteristics, origin, and pathogenicity of the GAA repeat expansion; the characterization of frataxin, the encoded protein, including its subcellular localization, structure, and function; the identification of cellular pathways disrupted by frataxin deficiency; and the redefinition of FRDA phenotypes based on genetic testing, along with the study of FRDA's natural history. In addition, efforts focused on the search for biomarkers to reflect diagnosis, disease severity, and progression and, most importantly, the identification and development of therapeutic approaches in both preclinical and clinical settings. The creation of cellular and animal models was crucial to this progress, as was the formation of consortia to collaboratively drive basic and clinical research forward. Now, 28 years after the gene discovery, although much remains to be understood about the disease's mechanisms and the development of effective therapies, the progress is undeniable. A thriving community has emerged, uniting researchers, health care providers, industry professionals, individuals with FRDA, their families, and dedicated volunteers. With this collective effort, a cure is within reach.