|
| Congenital myopathies | Histological features | Clinical features | Genes Mutated | Inheritance |
|
| MYOPATHIES WITH “RODS” (NEMALINE MYOPATHIES) | Presence of nemaline bodies or rods (protein aggregates) | Diaphragm weakness, distal weakness in lower extremities, congenital arthrogryposis, severe facial and bulbar weakness,
severe hypotonia, and hyporeactivity, progressive respiratory failure | TPM3 (1q21.3)
NEB (2q22.3)
ACTA 1 (1q42.13)
TPM2 (9p13.3)
TNNT1 (19q13.42)
KBTBD 13 (15q22.31)
CFL2 (14q13.1) | AD or AR
AR
AD or sporadic, AR
AD
AR(Amish private mutation)
AD
AR |
|
| MYOPATHIES WITH CENTRALIZED NUCLEI | | | | |
| Myotubular myopathies (XLMTM) | Muscle fibers similar to myotubes (normally observed at 8-15 weeks’ gestation) | Severe prenatal or neonatal myopathy, reduced fetal movements, polyhydramnios, swallowing difficulties, severe generalized hypotonia and weakness from birth, progressive ophthalmoparesis, severe respiratory insufficiency requiring ventilator support | MTM1 (Xq28) | Recessive X-linked |
| Centronuclear myopathies | High incidence of centrally and/or internally placed nuclei in rows in muscle fibers | Progressive ophthalmoparesis, early respiratory failure, progressive craniofacial deformities | DNM2 (19q13.1)
MYF6 (12q21.31)
CCDC78 (16p13.3)
BIN1 (2q14.3) | AD
AD
AD
AR |
|
| MYOPATHIES WITH FIBER TYPE DISPROPORTION | Type 1 fibers are consistently and significantly smaller (hypotrophic) than type 2 fibers.
Disproporzione del calibro delle fibre: fibre del tipo 1 (fibre lente) sono più piccole (almeno del 40%) rispetto alle fibre del tipo 2 (fibre veloci) | Low tone without other distinguishing characteristics | ACTA1 (1q42.1)
Locus 2 (Xq13.1-q22.1)
SEPN1 (1p36.11)
TPM3 (1q21.2)
TPM2 (9p13)
MYL2 (12q24.11) | AD
AR
AR
AD
AD
AR |
|
| MYOPATHIES WITH “CORES” | Cores: well-delimited, rounded areas devoid of oxidative staining, located in the cytoplasm of the muscle fibers. | | | |
| Central core myopathy | Single and central cores in muscle fibers | Decreased fetal movement during pregnancy, muscle pain/cramps, global hypotonia, weakness of the facial muscles, severe skeletal malformations,
possible malignant hyperthermia | RYR1 (19q13.1)
SEPN1 (1p36.11)
TTN (2q31.2)
MYH7 (14q12) | AR
AR or sporadic
AR
AD |
| Multiminicore myopathy | Multiple, short areas of sarcomere disorganization containing reduced numbers of mitochondria in skeletal muscle fibers | Neonatal hypotonia, global muscle weakness, delayed motor development | RYR1 (19q13.1)
SEPN1 (1p36.11)
TTN (2q31.2)
MYH7 (14q12) | AR
AR or sporadic
AR
AD |
|
