FXN

About FXN

FXN on chromosome 9q21.11 encodes frataxin, a small mitochondrial protein involved in the assembly of iron sulfur clusters, which are essential cofactors for energy production. Friedreich ataxia, the most common inherited ataxia, is usually caused by an expanded GAA trinucleotide repeat in the first intron of FXN on both copies of the gene, which silences transcription and reduces frataxin levels. It is inherited in an autosomal recessive pattern. Symptoms usually begin in childhood or adolescence with progressive unsteadiness, loss of coordination, slurred speech, and loss of reflexes and position sense, and hypertrophic cardiomyopathy is a frequent and important complication, along with scoliosis and diabetes. It was first described by the German physician Nikolaus Friedreich in the 1860s. Omaveloxolone became the first drug approved specifically for Friedreich ataxia in the United States in 2023.