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Título

Atypical Manifestations of Late-Onset Friedreich’s Ataxia – case report

RESUMO

A 57-year-old female who four to five years before, started with a progressive ataxia in four limbs and gait. She also presents progressive dysarthria and dysphagia, and severe weight loss. At examination, she presented exacerbated deep tendon reflexes with Babinski sign, vibratory sensory loss in distal inferior limbs, head tremor, cognitive impairment in executive functions and verbal fluency. She had no vestibular symptoms or parkinsonism findings upon examination. No family history of neurological diseases was reported.
Laboratory investigation of neoplastic, infectious, immune-mediated, endocrine and nutritional deficiencies showed no abnormalities. Brain magnetic resonance imaging (MRI) showed extensive microangiopathy findings. Genetic testing presented 100 repetitions in both alleles of Frataxin (FXN) gene for Friedreich ataxia.
Friedreich ataxia is an autosomal recessive disease, the main cause of hereditary ataxia. Patients usually present symptoms before 25 years old. Our patient started symptoms at 52 years old, an atypical presentation. Patients usually will have a positive family history for the disease.
In most cases, patients present aguanine-adenine-adenine (GAA) trinucleotiderepeat in intron 1 of both alleles of the FXN gene. Positive cases vary from 66-1700 repeats. Normal alleles will have between 7-34 repeats. Our patient’s number of repeats is located on the low end of positive cases, probably the cause for her atypical presentation.
Ataxia in four limbs and gait is a cardinal sign, present in most patients. Deep tendon reflexes are usually lost. Exacerbated reflexes are atypical. Motor weakness involving inferior limbs is a common symptom. Also, sensory loss in the distal limbs affects could be present, predominately involving proprioception and vibration sense. Dysarthria and dysphagia are common features.
The main cause of death in these patientsis cardiac dysfunction, due to hypertrophic cardiomyopathy frequently present in the disease, absent in our patient, probably related to the late onset of the disease.
Even though, case reports of late onset Friedreich ataxia are frequently published, we present a report with mainly atypical manifestations and in which the patient has no family history of the disease. Therefore, it is a diagnosis sorely relying in genetic testing. We should consider in clinical practice hereditary diseases, even when symptoms are atypical, and patients have no family history.

Palavras Chave

Ataxia; Ataxia de Friedreich