DUX4 and facioscapulohumeral muscular dystrophy: For example, this initial work has: 1) identified a blood vessel-associated cell lineage that had, at some point in its developmental history, activated DUX4 expression, and 2) implicated the pericyte lineage as a novel source of developmental DUX4 expression that could impact skeletal muscle formation, growth, repair, and regeneration, thus potentially playing a role in FSHD pathology.