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This is a natural history study prospectively investigating neuroimaging markers of disease progression in children and adults with Friedreich ataxia (FA). There will be three assessment periods (baseline, 12 and 24 months). The study will include approximately 200 individuals with FA and 100 matched controls recruited across the six international academic sites. Other assessments will include secondary clinical and cognitive markers, as well as exploratory blood markers.

Friedreich ataxia (FA) is a multi-system progressive disorder with the most prevalent and prominent symptoms relating to dysfunction in the central and peripheral nervous system, including, loss of balance and coordination, frequent falls, loss of ambulation, dysarthria, dysphagia and loss of vision and hearing. Other symptoms include cardiomyopathy, diabetes, scoliosis and fatigue. Age of onset can vary but most often presents during childhood, ages 5-15 years.

There is currently no cure and no disease-modifying treatment. Drug candidates to potentially treat FA are under development; however, there is a lack of well- characterized neuroimaging biomarkers for testing their efficacy in clinical trials, hampering this process. Establishing disease-specific neuroimaging biomarkers to track disease progression requires high-quality longitudinal data from large cohorts of patients, compared to controls. In rare diseases, such as FA, this can only be achieved through multi-site collaboration.

The aim of TRACK-FA is to develop an FA neuroimaging dataset from brain and spinal cord that is suitable for assessing the potential value of neuroimaging biomarkers and providing a basis for instituting them in clinical trials. The dataset will comprise a range of neuroimaging measures to assess changes in spinal cord and brain regions that have previously shown to be compromised in individuals with FA. In addition to neuroimaging measures, TRACK-FA will also include clinical, cognitive data and biospecimen data. The TRACK-FA dataset will provide a unique opportunity for academic researchers in collaboration with industry partners to access the images, subsidiary data, and associated clinical data for community research.

This multi-centre study is a collaborative effort across six academic institutions, together with industry partners and the Friedreich's Ataxia Research Alliance USA (FARA).

Inclusion Criteria:

• Age â‰� 5 years

• Written informed consent provided

• Individuals with FA must have a genetic confirmation of diagnosis and be biallelic for a GAA repeat length > 55 in intron 1 of FXN and/or have a GAA repeat length > 55 in intron 1 of FXN in one allele and another type of mutation that is inferred to cause loss of function in the second FXN allele

• Individuals with FA must have an age of disease onset â‰� 25 years

• Individuals with FA must have a disease duration â‰� 25 years

• Individuals with FA must have a Friedreich Ataxia Rating Scale (FARS) Functional staging score of â‰� 5 and total modified FARS (mFARS) score of â‰� 65 on enrolment

Exclusion Criteria:

• Age < 5 years

• Unable to provide written informed consent

• Magnetic resonance contraindications (e.g. pacemaker or other metallic surgical implants)

• Presence of metallic dental braces

• Pregnancy (ascertained via a question or test as mandated at particular sites)

• Individuals with FA must not have acute or ongoing medical or other conditions that, after discussion between the Site Investigator and steering committee, is deemed to interfere with the conduct and assessments of the study

• Individuals with FA must not have another neurological condition apart from FA

• Individuals with FA must not have other neurologic conditions that, in the opinion of the Site Investigator, would interfere with the conduct and assessments of the study

• Controls must not have a diagnosed psychiatric or neurological condition

• Controls must not have acute or ongoing medical or other conditions that would interfere with the conduct and assessments of the study

• Controls must not be siblings of individuals with FA whose carrier status (i.e., confirmed carrier, confirmed non-carrier, or obligate carrier) is unknown.