Motor Outcomes to Validate Evaluations in Pediatric FSHD (MOVE Peds)

Inclusion Criteria:

* Age 5-17 years.
* Genetically confirmed FSHD (types 1 or 2).
* Symptomatic weakness (facial, shoulder, core, or limb weakness)
* Able to complete a 10-meter walk without the support of another person in less than 12 seconds (canes, walking sticks, and braces allowed; no walker). In order to include early onset participants up to 8 individuals will be entered with baseline 10MWR \> 12 seconds or who are no longer ambulatory (≤10%)

Exclusion Criteria:

* Unwilling or unable to provide informed consent or assent. Any other medical condition which in the opinion of the investigator would interfere with study participation.
* Malignancy with ongoing treatment with chemotherapeutic agents or anabolic agents
* Use of immunosuppressants including prednisone or performance enhancing drugs including testosterone within 6 months
* Pregnancy
* Recent or ongoing infection
* Presence of contraindication to performance of MRI: pacemaker, metallic foreign body in eye, brain aneurysm clip (unless documented as MRI compatible)
* In the opinion of the investigator unable to follow directions for standardized testing

  * Note: Not being able to complete MRI will not result in a screen failure. If subject is not able to complete the procedure due to fear or anxiety, they will have the opportunity to try again at later visits. However, Subject must be willing to attempt to perform the MRI to meet inclusion/exclusion criteria