Clinical Variability and Diagnostic Considerations in Facioscapulohumeral Muscular Dystrophy: A Case Series

BACKGROUND: Facioscapulohumeral muscular dystrophy (FSHMD) is a genetic disorder affecting muscles of the face, shoulder girdle, and abdomen, leading to variable muscle weakness and functional impairment. CASE PRESENTATION: This case series describes 3 patients with FSHMD. Case 1 involved a 22-year-old female with suspected bilateral shoulder instability. Case 2 was a 21-year-old male with bilateral trapezius atrophy following a skiing injury. Case 3 was a 19-year-old female with significant bilateral scapular winging. OUTCOME AND FOLLOW-UP: The presence of significant bilateral weakness of the serratus anterior, trapezius, or both led the clinician to suspected FSHMD and refer for further follow-up. DISCUSSION: The cases highlight the variability in FSHMD presentation and the importance of early diagnosis and referral. Misdiagnosis is common due to overlapping symptoms with other conditions, such as long thoracic nerve palsy or spinal accessory nerve palsy. JOSPT Cases 2025;5(2):74-81. Epub 17 March 2025. doi:10.2519/josptcases.2025.0100