Table 3.
Comparison of Amish nemaline rod (ANM) and X-linked centronuclear (CNMX) myopathies
| ANM | CNMX | |
|---|---|---|
| Cellular biology | ||
| Gene | TNNT1 | MTM1 |
| Inheritance pattern | Autosomal recessive | X-linked recessive |
| mRNA size | 1239 bases | 3452 bases |
| Protein | Type 1 troponin T | Myotubularin |
| Expression | Sarcoplasm | Sarcoplasm |
| Localization | Sarcomere | Multiple locations |
| Function | Calcium-regulated contraction | 3-PI phosphatase |
| Pathology | ||
| Muscle type | Slow skeletal | Ubiquitous |
| Fiber type | Slow (Type 1) | Ubiquitous |
| Myofiber appearance | Atrophy/ hypoplasia | Hypotrophy |
| Myonecrosis | No | No |
| Inflammation | No | No |
| Fiber regeneration | Yes | No |
| Clinical | ||
| Muscle weakness | Progressive | Birth |
| Muscle wasting | Progressive | Birth |
| Survival, mean ±SD (months) | 18±10 | – |