TABLE 2.

Classification of myofibrillar myopathies

Type	Inheritance Gene localization		Initial weakness	CK	Biopsy
Desmin — adult onset (h IBM1& LGMD 1D/E)α MFM1	AD or AR (6%)	2q35	Hands or legs	Moderately, increased <5× normal	Myopathy, occasional rimmed vacuoles; sub- sarcolemmal granules, desmin bodies
αB-crystallin — early - mid adult MFM2	AD or AR	11q22	Proximal & leg distal	Mild elevation	Myopathy, desmin increase
Myotilin adult (LGMD 1A) β MFM3	AD or sporadic	5q31.2	proximal or distal nasal, dysarthria	Normal to 15 × elevated	Myofibrillar myopathy, rimmed vacuoles, hyaline / rod inclusions, desmin
ZASP— late adult MFM4	AD	10q23.2	proximal or in 9% distal	Normal or mild elevation	Myofibrillar myopathy, small vacuoles, desmin aggregates
Myofibrillar with Cardiomyopathy - adult	AD	10q22.3 Similar to ZASP	Distal	Normal or mild elevation	Myofibrillar myopathy
Filamin C Mid to late adult MFM5 (see Table 3)	AD	7q32.1	proximal & respiratory	2–8 × elevation	Myopathy, hyaline mass, vacuoles, rods & desmin aggregates
BAG3 Childhood MFM6	AD	10q25.2-q26.2	Proximal > distal, cardiac	3–15 × elevation	Myopathy, congophilia, desmin accumulation, small vacuoles
Scapuloperoneal aka hyaline body myopathy — adult	AD	Xq26 FHL1	Distal legs Scapular winging	1.5–10 × elevation	Myopathy, hyaline bodies with focal desmin inclusions
SEPN1 – child - aka Congenital muscular dystrophy with desmin inclusions	AR	1p36-p35	proximal, rigid spine & cardiac	Normal or mild elevation	Myopathy, vacuoles, desmin inclusions

α Autosomal dominant hereditary IBM1, with early quadriceps muscle involvement and later ankle dorsiflexion weakness, has been linked to a mutation in the desmin gene (93). Autosomal dominant LGMD 1D/E, with cardiac conduction defect and dilated cardiomyopathy, is also linked to the desmin gene (155). A dominant neurogenic Kaeser type scapuloperoneal phenotype also been described to harbor a desmin gene mutation (99).

β Autosomal dominant LGMD 1A has been linked to a mutation in myotilin, the causative gene of myofibrillar myopathy 3.

BAG3, BCL2-associated athanogene 3;CK; creatine kinase; FHL1; Four-and-a-half-LIM protein 1, hIBM, hereditary inclusion body myopathy; LGMD, limb girdle muscular dystrophy; SEPN1, Selenoprotein N, 1; ZASP, Z-band alternatively spliced PDZ-motif-containing protein aka LDB3, Lim domain-binding 3.