General description

Friedreich's ataxia (FA) is a progressive neurodegenerative disorder caused by pathogenic variants in the frataxin gene and inherited in an autosomal recessive manner. It primarily manifests with neurological symptoms, including progressive ataxia affecting the trunk and limbs, leading to unsteady walking, poor coordination, and eventual reliance on assistive devices. Sensory impairments such as loss of proprioception and vibration sense, along with reduced or absent reflexes, are also common. Dysarthria, characterized by slurred speech due to facial muscle incoordination, is another key feature. Additionally, patients may experience peripheral neuropathy, muscle weakness, spasticity, and other neurological abnormalities.

Beyond the nervous system, FA presents with systemic manifestations, including hypertrophic cardiomyopathy, which can progress to dilated forms and lead to heart failure or arrhythmias. Impaired glucose tolerance or diabetes mellitus occurs in some patients due to insulin resistance. Skeletal abnormalities such as scoliosis and pes cavus (high-arched feet) are frequently observed. Other associated symptoms include hearing loss, optic atrophy, urinary dysfunction, and autonomic disturbances like cold or cyanotic lower limbs.

The neurological symptoms and imaging findings of Friedreich's ataxia are similar to those of Ataxia with isolated vitamin E deficiency (AVED). However, unlike Friedreich's ataxia, AVED can be treated with vitamin E supplementation. Therefore, when Friedreich's ataxia is suspected, measuring blood vitamin E levels is crucial for an accurate diagnosis.

References

1. Bond, K. M., et al. "Dentate update: imaging features of entities that affect the dentate nucleus." American Journal of Neuroradiology 38.8 (2017): 1467-1474.