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Friedreich ataxia is inherited in an autosomal recessive pattern and is caused by a GAA trinucleotide repeat expansion in the FXN gene. This expansion reduces the production of frataxin, a mitochondrial protein, leading to neurodegeneration and the typical clinical features. Since two mutated copies are necessary for disease, carriers are usually asymptomatic. Most cases involve expansions on both alleles, though a disease allele can pair with a different mutation on the other allele and still be autosomal recessive. The other options are incorrect because a dominant pattern would require only one mutated copy to cause disease, and the specific repeats mentioned (CAG, CGG) are associated with other disorders (Huntington disease and Fragile X, respectively).