Relapsing peripheral facial palsy: An unusual early sign of Friedreich ataxia

Abstract

A 4-year-old child presented with peripheral left facial palsy. Neurological examination was normal except for deep tendon areflexia in the lower limbs. Serologic evaluation and cerebral magnetic resonance imaging to rule out post-infectious causes were normal. Electroneurography (ENG) showed absent sensory action potentials. After 15 days, the patient experienced a relapse of peripheral left facial palsy; ENG was unchanged, and somatosensory evoked potentials showed posterior column involvement. Genetic analysis demonstrated GAA repeat expansion on both alleles (860 and 900 GAA triplets) of the frataxin gene, and the child was diagnosed with Friedreich ataxia. Neurological findings at the last examination, performed at 7 years of age, were unchanged except for mild bilateral pes cavus. Peripheral seventh cranial nerve palsy could be an early and unusual sign of central nervous system degeneration and axonal sensory neuropathy. Its occurrence in this patient provides further evidence that Friedreich ataxia may have a varied clinical presentation at onset. In accordance with other studies, we believe that the size of both GAA expansions affect the age at onset of the disease, despite atypical phenotype.

Keywords

Facial palsy - axonal neuropathy - Friedreich ataxia - child