Multiple Sclerosis in a Patient with Friedreich's Ataxia
Yang Yu1, Hani Kushlaf1
1Neurology, University of Cincinnati
To report clinical features in a patient with genetically confirmed Friedreich’s Ataxia (FRDA) that led to the definitive diagnosis of multiple sclerosis (MS). 
FRDA is caused by homozygous GAA trinucleotide repeat expansion in the Frataxin gene. While white matter abnormalities are seen in FRDA, none described so far have been compatible with a diagnosis of MS. 

Case Report: 

A 22-year-old woman was diagnosed with FRDA at ten years of age. She presented with gait ataxia at age eight years. Initial examination showed ocular dysmetria, areflexia, intention tremor, dysmetria on finger-to-nose testing, and gait ataxia. Genetic testing showed 933 and 800 repeats in alleles 1 and 2, respectively.  

At 20 years of age, she was non-ambulatory with moderate ataxic dysarthria, severe truncal and extremity ataxia. At 21, she developed acutely worsening paresthesia in her fingers, fatigue, and bilateral arm and leg weakness. Examination revealed new findings of weakness in the right greater than the left arm and leg and loss of joint position sense in her fingers. MRI brain and total spine demonstrated multifocal hyperintense lesions in supratentorial and infratentorial locations and the cervical spinal cord; two lesions demonstrated enhancement. CSF analysis revealed 11 WBCs (94% lymphocytes), normal protein, and three unique oligoclonal bands. Serum NMO antibody was negative. Additional extensive serologic testing for the MS differential diagnosis was negative. High-dose intravenous steroids resulted in improvement of arm strength.  

Three months later, she developed right foot numbness. MRI brain demonstrated a new enhancing white matter lesion over the right posterior horn of the lateral ventricle.  

The definitive diagnosis of multiple sclerosis in a FRDA patient is novel and requires careful reconciliation of the symptoms, clinical exam findings, and ancillary testing. The development of symptoms incompatible with FRDA should prompt clinicians to consider additional neurologic diagnoses.