Characterization of the Cardiac Phenotype of Friedreich's Ataxia (FRDA)

Friedreich's ataxia (FRDA) is an autosomal recessive disease characterized by loss of coordination and cardiomyopathy. It is the most common form of inherited ataxia with an incidence in 1/50,000 in the Caucasian population. FRDA is associated with progressive damage to the nervous system, resulting in symptoms ranging from gait disturbance to speech problems, as well as diabetes and heart disease. The heart disease manifests as cardiomyopathy, and is responsible for approximately 60% of deaths from FRDA. This study is designed to characterize the cardiac manifestations of the disease using exercise, MRI, ECHO and serum parameters, in the context of the neurological disease. In addition, this study will demonstrate that corneal confocal microscopy (CCM) may also provide a biomarker for FRDA.

The focus of this study is to assess cardiac dysfunction in individuals with FRDA using 4 modalities: hand crank exercise, cardiac magnetic resonance (CMR) imaging, echocardiography (ECHO), and serum measurements of cardiac status, including high sensitivity troponin, a measure of cardiac myocyte damage; N-terminal prohormone of brain natriuretic peptide (NTproBNP), a measure of heart failure; and creatine phosphokinase (CPK), a general measure of muscle damage. While there have been individual studies of some of these modalities, there are no studies that correlate these parameters and it is not known which parameters are more sensitive to cardiac dysfunction. This preliminary study will help define the parameters most useful in assessing the cardiac involvement in FRDA. In addition, the study will investigate noninvasive tests and procedures that may serve as biomarkers for the neurologic disease. In other neurological diseases, non-invasive examination of the number and structure of nerve cells in the cornea has been assessed as an indication of disease progression.