Table 2.
Characteristics of genetically-confirmed FSHD1 in China, 2001 to 2020.
| Total = 997 | |
|---|---|
| Baseline characteristics | |
| Demographic | |
| Sex, M/F, n (%) | 534 (53.4)/463 (46.4) |
| Age, y, median (range) | 36 (3-87) |
| Clinical | |
| Onset age at first-ever muscle weakness (patient-reported; symptomatic plus asymptomatic patients, n = 842), y, median (range) | 16 (1-81) |
| Symptomatic plus asymptomatic mutation carriers, n (%) | 861 (86.4%) |
| Nonpenetrant mutation carriers, n (%) | 124 (12.4%) |
| Phenotypic classification (CCEF) (evaluated participants = 655) | |
| Category A | 458 (69.9%) |
| Category B | 43 (6.6%) |
| Category C | 136 (20.8%) |
| Category D | 18 (2.7%) |
| Assessments (symptomatic plus asymptomatic patients), median (range) | |
| MRC sum score (0–140) (evaluated participants = 548) | 117.8 (59.5-140.0) |
| FSHD clinical score (0–15) (evaluated participants = 510) | 7 (0-13) |
| Clinical severity scale (0–5) (evaluated participants = 518) | 3 (0-5) |
| Age-corrected clinical severity score (0–10 000) | 181.9 (0-1285.7) |
| Genetic/epigenetic | |
| Length of contracted D4Z4 repeat array, kB, median (range) | 23.5 (10.0-36.5) |
| Size of contracted D4Z4 repeats, units, median (rang) | 5 (1-9) |
| 1-3 D4Z4 repeats, n (%) | 267 (26.8) |
| 4-6 D4Z5 repeats, n (%) | 594 (59.6) |
| 7-9 D4Z6 repeats, n (%) | 136 (13.6) |
| Mosaic mutation, n (%) | 40 (4.0) |
| D4Z4 Methylation level (tested participants = 690), percentage, median (range) | 41 (14-69) |
| Disease progression | |
| Proportion of independent ambulation loss (n/followed-up cases) | 12.0 (117/977) |
| Onset age at onset of independent ambulation loss, y, median (range) | 38 (9-87) |
| Durationa, mean (SD), y, median (range) | 20 (0-69) |
| Proportion of wheelchair dependency (n/followed-up cases) | 8.9 (87/977) |
a
Duration was derived by deduct the onset age at first-ever muscle weakness from the onset age at onset of independent ambulation loss.