TABLE 1.
Baseline characteristics of 428 patients with myotonic dystrophy type 1
| Age, years, mean (range) | 33 (2 to 81) |
| Male, n (%) | 192 (45) |
| Cytosine-thymine-guanine repeats, n (%) | |
| <200 | 59 (13.8) |
| 200 to 400 | 55 (12.9) |
| 401 to 850 | 92 (21.5) |
| 851 to 1100 | 78 (18.2) |
| 1101 to 1500 | 94 (21.9) |
| >1500 | 50 (11.7) |
| Koch classification, n (%) | |
| Infantile | 72 (16.8) |
| Early adult | 157 (36.7) |
| Adult | 111 (25.9) |
| Mild or late form | 56 (13.1) |
| Unknown | 32 (7.5) |
| Degree of neuromuscular impairment, n (%) | |
| None | 49 (11.4) |
| Mild | 228 (53.3) |
| Moderate to severe | 139 (32.5) |
| Unknown | 12 (2.8) |
| Mean PR interval, ms | 176 |
| Mean QRS interval, ms | 97 |
| Mean corrected QT, ms | 420 |