Mortality associated with facioscapulohumeral muscular dystrophy: A systematic literature review

BACKGROUND: Facioscapulohumeral muscular dystrophy (FSHD) is a rare genetic disorder characterized by progressive muscle weakness and atrophy. The onset of FSHD ranges between infancy and adulthood, initially affecting the face, shoulders, and upper arms. Limited evidence exists regarding the disease characteristics and associated mortality. MATERIALS AND METHODS: A systematic literature review was conducted to generate evidence on mortality in FSHD. The Embase and MEDLINE databases were searched via Ovid to identify relevant publications on mortality (from inception to August 20, 2024), excluding editorials, notes, letters, and case reports. Information on studies, participant characteristics, and mortality data were extracted from the included publications. The quality of included cohort studies was appraised using the Newcastle-Ottawa Scale. RESULTS: Eight studies published between 1979 and 2016 across five countries encompassing 1091 patients with FSHD were assessed; 1.6% patients were included from studies on early-onset FSHD and 98.4% from studies on both early-onset and classical phenotypes. Mortality was reported in 27.8% of patients with early-onset FSHD (mean age at death 18.4 years, range: 15.0-31.0 years) and 7.9% of patients with both phenotypes (mean age at death 62.6 years, range: 11.0-83.3 years). Respiratory or cardiac-related causes of death were reported. CONCLUSION: This review reveals premature mortality and critical knowledge gap regarding life expectancy and survival outcomes in FSHD. Limited data suggest survival implications in both early-onset and all FSHD phenotypes, underscoring the need for prospective longitudinal studies to better characterize the mortality patterns in FSHD, identify risk factors, and inform clinical management strategies.