Table 5.

Main characteristics of filaminopathies

	FLNC rod domain mutations associated with MFM phenotype	Distal myopathy caused by FLNC actin-binding domain mutations
Inheritance pattern	Autosomal dominant	Autosomal dominant
Age at onset	Fourth to sixth decade of life	Third to fourth decade of life
Initial symptoms	Proximal lower limb weakness	Thenar muscle weakness
Advanced illness	Involvement (weakness) of proximal upper limbs, distal limbs and trunk muscles	Calf muscle weakness, proximal muscle weakness
Cardiac involvement	Frequent	Insufficient data (reported in two out of 13 patients)
Respiratory weakness	Regular in advanced illness	No
Muscle imaging of lower limbs (most affected muscles)	Thigh: semimembranosus, adductor magnus and longus, biceps femoris, vastus intermedius and vastus medialis	Thigh: semimembranosus, semitendinosus, biceps femoris, adductor magnus
	Lower leg: soleus, gastrocnemius medialis, tibialis anterior	Lower leg: soleus, gastrocnemius lateralis and medialis, peroneal muscles
Creatine kinase level	Normal up to 10× increased	Up to 2.5× increased
Muscle biopsy	Non-specific changes, dystrophic pattern in advanced disease	Non-specific changes, dystrophic pattern in advanced disease
	Polymorphous cytoplasmic protein aggregates (plaque-like formations, convoluted serpentine inclusions, spheroid bodies)	No myofibrillar myopathy-typical protein aggregation
	Rimmed vacuoles	No rimmed vacuoles
	Core-like lesions, Type I fibre predominance	Areas lacking oxidative enzyme activity (moth-eaten appearance)
	EM: myofibrillar disintegration, deposits of granulofilamentous material, tubulofilamentous inclusions, nemaline rods, autophagic vacuoles	EM: no myofibrillar pathology

EM = electron microscopy.