An overexpression of fibroblast growth factor (FGF) and FGF receptor 4 in a severe clinical phenotype of facioscapulohumeral muscular dystrophy

We evaluated the expression of a select panel of growth factors and their receptors, including fibroblast growth factor 1 (FGF‐1), fibroblast growth factor 2 (FGF‐2), platelet‐derived growth factor (PDGF), FGF receptor 1 (FGF‐R1), FGF receptor 3 (FGF‐R3), FGF receptor 4 (FGF‐R4), PDGF receptor α (PDGF‐Rα), PDGF receptor β (PDGF‐Rβ), and heparan sulfate proteoglycan (HSPG), in muscle biopsy specimens from nine facioscapulohumeral muscular dystrophy (FSHD) patients using immunohistochemistry. Two cases of Duchenne‐type muscular dystrophy (DMD), two of Becker‐type muscular dystrophy (BMD), and one of limb‐girdle‐type muscular dystrophy (LGMD) were also investigated. Widespread immunostaining for FGF‐1 and FGF‐2 on the sarcolemma and overexpression of FGF‐R4 in endomysial and perimysial connective tissue were seen in one patient with a severe clinical phenotype of FSHD who had respiratory failure. Standard histochemistry in this patient revealed marked interstitial fibrosis and lobulated fibers. The overexpression of FGF and FGF‐R4 in this severe FSHD case may be associated with the muscle fibrosis and disease severity. © 2000 John Wiley & Sons, Inc. Muscle Nerve 23: 490–497, 2000.