Table 1.
Summary of clinical features and results of histological analysis
| MH and RM | MH | RM | |
|---|---|---|---|
| Clinical features | n = 50 (%) | n = 31 (%) | n = 19 (%) |
| Sex: male | 37 (74) | 20 (65) | 17 (89) |
| Positive IVCT (MHS or MHE) or diagnostic MH mutation (according to EMHG) | 35 (70) | 31 (100) | 4 (21) |
| Permanent muscle weakness | 11(22) | 3 (10) | 8 (42) |
| Histopathological analysis | n = 50 | n = 31 | n = 19 |
| Mean age at biopsy (range) | 34 (5–67) | 37 (10–67) | 31 (5–61) |
| Normal | 5 (10) | 3 (10) | 2 (11) |
| General myopathic features | 45 (90) | 28 (90) | 17 (89) |
| Increased fibre size variability | 44 (88) | 27 (87) | 17 (89) |
| Increased number of fibres with internal nuclei (> 3%) | 30 (60) | 20 (65) | 10 (53) |
| Increased number of fibres with central nuclei (part of group above) | 18 (36) | 13 (42) | 5 (26) |
| Type 1 fibre predominance | 13 (26) | 7 (23) | 6 (32) |
| Prominent lipid vacuoles(1) | 3 (6) | 0 (0) | 3 (16) |
| Necrotic fibres(2) | 3 (6) | 0 (0) | 3 (3) |
| Mild increase in connective tissue in endomysium | 2 (4) | 1 (3) | 1 (5) |
| Abnormalities on oxidative staining | 26 (52) | 18 (58) | 8 (42) |
| Unevenness(3) | 24 (48) | 20 (65) | 4 (21) |
| Central cores | 7 (14) | 6 (19) | 1 (5) |
| Ring -fibres | 4 (8) | 2 (6) | 2 (11) |
| Multiple minicores | 3 (6) | 2 (6) | 1 (5) |
| Abnormalities on trichome staining | |||
| Nemaline rods | 1 (2) | 1 (3) | 0 (0) |
| Electron microscopy (EM) | n = 26 | n = 16 | n = 10 |
| Normal | 4 (15) | 3 (19) | 1 (10) |
| Abnormal | 22 (85) | 13 (81) | 9 (90) |
| Z-band streaming | 8 (31) | 6 (38) | 2 (20) |
| Cores (central cores or minicores) | 8 (31) | 6 (38) | 2 (20) |
| Abnormal mitochondria | 4 (15) | 1 (6) | 3 (30) |
| Lipid droplets | 1 (4) | 0 (0) | 1 (10) |
| Combined analysis of LM an and EMa | n = 50 | n = 31 | n = 19 |
| Cores (central cores or minicores) | 14 (28) | 11 (35) | 3 (16) |
| Central coresa | 8 (16) | 7 (23) | 1 (5) |
| Multiple minicoresb | 6 (12) | 4 (13) | 2 (11) |
aCentral cores were observed by light microscopy (LM) in patients 3, 4, 11, 19, 20, 24 (all MH) and 35 (rhabdomyolysis); and on EM in patients 19, 24, 29 (all MH), and 35 (rhabdomyolysis)
bMultiple minicores were observed by LM in patients 21 and 27 (MH) and 47 (rhabdomyolysis), and on EM in patients 5, 27, 31 (MH), 44 and 47 (rhabdomyolysis)
(1) and (2)p = 0.02 (Chi-square test)
(3)p < 0.05 (Chi-square test)