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

Friedreich's Ataxia - Inclusion Criteria:

* Males and females, age 12 to 50
* Willing and able to provide informed consent (adolescents will need to provide assent and a parent to provide consent)
* Definitive diagnosis of FRDA, based on clinical phenotype and genotype
* Left ventricle ejection fraction measured by ECHO of \>35% (If results of an ECHO are not available for a potential subject, then an ECHO will first be performed and subjects with an LVEF \<35% will not be required to perform the CPET)

Friedreich's Ataxia - Exclusion Criteria:

* Signs and symptoms of cardiac failure
* Moderate to severe atrial or ventricular arrythmias
* History of angina pectoris
* Implanted pacemaker and/ or defibrillator or any other device that would preclude MRI assessment
* Any form of dialysis; Severe or end-stage CKD (CKD 4 or 5, eGFR \< 30 ml/min/1.73 m2) without dialysis; eGFR 30 to 40 ml/min/1.73 m2 without dialysis; Acute kidney injury (If a recent assessment is not available, then a blood test to assess kidney function will be performed prior to cardiac MRI)
* Females who are pregnant
* Receipt of an investigational drug within 30 days or 5 half-lives, whichever is longer, prior to screening, or active enrollment in an investigational medication or device study
* Unable to undergo cardiac MRI with gadolinium contrast or claustrophobia
* Clinical history or evidence of Type 1 or Type 2 Diabetes mellitus
* Any condition, disorder, or abnormal laboratory test findings at screening which, in the judgment of the investigator, would interfere with the individual's ability to comply with all study requirements, or would require the administration of treatment during the study that could potentially affect the interpretation of the study data, or would place the individual at an unacceptable risk by his/ her participation in the study

Normal controls - Inclusion Criteria:

* Males and females, age 12 to 30
* Willing and able to provide informed consent (Adolescents will need to provide assent and a parent to provide consent)
* Matched age, gender and ethnicity to the FRDA group
* Capable of undergoing the various modalities of cardiac assessment
* Left ventricle ejection fraction measured by ECHO of \>35% (If results of an ECHO are not available for a potential subject, then an ECHO will first be performed and subjects with an LVEF \<35% will be withdrawn from the study)

Normal controls - Exclusion Criteria:

* Individuals not deemed in good overall health by the investigator will not be accepted into the study
* Signs and symptoms of cardiac failure
* Moderate to severe atrial or ventricular arrhythmias
* History of angina pectoris
* Implanted pacemaker and/ or defibrillator or any other device that would preclude MRI assessment
* Any form of dialysis; Severe or end-stage CKD (CKD 4 or 5, eGFR \< 30 ml/min/1.73 m2) without dialysis; eGFR 30 to 40 ml/min/1.73 m2 without dialysis; Acute kidney injury (If a recent assessment is not available, then a blood test to assess kidney function will be performed prior to cardiac MRI)
* Females who are pregnant or lactating
* Receipt of an investigational drug within 30 days or 5 half-lives, whichever is longer, prior to screening, or active enrollment in an investigational medication or device study
* Unable to sit with back support
* Unable to undergo cardiac MRI with gadolinium contrast or claustrophobia
* Unable to undergo exercise tests
* Clinical history or evidence of Type 1 or Type 2 Diabetes mellitus
* Any condition, disorder, or abnormal laboratory test findings at screening which, in the judgment of the investigator, would interfere with the individual's ability to comply with all study requirements, or would require the administration of treatment during the study that could potentially affect the interpretation of the study data, or would place the individual at an unacceptable risk by his/ her participation in the study