This study was closed due to inability to to recruit.

To characterize the clinical and molecular phenotype of FSHD.

The purpose of this study is to validate alterations in therapeutically relevant biomarkers in muscle tissue from FSHD patients. These biomarkers are responsive to the upregulation of the DUX4 gene and protein, which is the fundamental molecular defect in FSHD. In anticipation of a future clinical trial, the Investigators intend to assess the correlation between the expression of these relevant biomarkers and clinical functional measures. The Investigators will also explore the utility of muscle MRI in identifying regions of muscle suitable for sampling for relevant biomarkers, as MRI-related signal changes have been proposed as an anatomic marker of early FSHD pathology.

Inclusion Criteria:

• 13 years or older
• Genetically proven FSHD1 or FSHD2 as determined by the investigators

Exclusion Criteria:

• Inability to complete an MRI scan (Adults only).
• Other medical or cognitive issues that, in the opinion of the examiner, preclude accurate functional assessment.

Subjects 13 years or older with facioscapulohumeral muscular dystrophy (FSHD).

We will be willing to share de-identified data following the execution of a Data Use Agreement.