Table 1.
Historical and demographic characteristics of 364 children diagnosed with myasthenia gravis from 1966 through 2015
| No. (%) | ||||
|---|---|---|---|---|
| Characteristic | JMG (N=217) |
CMS (N=141) |
LEM (N=6) |
Overall (N=364) |
| Sex | ||||
| Male | 73 (33.6) | 67 (47.5) | 5 (83.3) | 145 (39.8) |
| Female | 144 (66.4) | 74 (52.5) | 1 (16.7) | 219 (60.2) |
| Race | ||||
| African American | 5 (2.3) | 4 (2.8) | 0 (0.0) | 9 (2.5) |
| Asian | 6 (2.8) | 2 (1.4) | 0 (0.0) | 8 (2.2) |
| Caucasian | 136 (62.7) | 93 (66.0) | 6 (100.0) | 235 (64.4) |
| Unspecified | 67 (30.9) | 42 (29.8) | 0 (0.0) | 109 (29.9) |
| Prematurity* | ||||
| Yes | 10 (4.6) | 11 (7.8) | 0 (0.0) | 21 (5.8) |
| Family history | ||||
| Myasthenia | 4 (1.8) | 26 (18.4) | 0 (0.0) | 30 (8.2) |
| Consanguinity | 0 (0.0) | 3 (2.1) | 0 (0.0) | 3 (0.8) |
| Age at onset in years | ||||
| Median (range) | 12.8y (0.8-18.3) | 0y (0.0-13.3) | 9.5y (0.0-14.8) | 5.8y (0.0-18.3) |
| Age at diagnosis in years | ||||
| Median (range) | 13.5y (0.9-18.8) | 5.1y (0.0-18.9) | 12.6y (7.6- 18.7) | 10.8y (0.0-18.9) |
| Symptoms at onset | ||||
| Weakness | 71 (32.7) | 37 (26.2) | 5 (83.3%) 1 | 113 (31.0) |
| Drooping of eyelids | 111 (51.2) | 45 (31.9) | (16.7) | 157 (43.1) |
| Diplopia | 52 (24.0) | 0 (0.0) | 1 (16.7) | 52 (14.3) |
| Swallowing, chewing, speech difficulties | 54 (24.9) | 23 (16.3) | 0 (0.0) | 77 (21.2) |
| Floppy baby | 1 (0.5) | 21 (14.9) | 0 (0.0) | 22 (6.0) |
| Feeding difficulties | 1 (0.5) | 62 (44.0) | 1 (16.7) | 64 (17.6) |
| Respiratory difficulties | 7 (3.2) | 54 (38.3) | 0 (0.0) | 61 (16.8) |
| Involvement | ||||
| Ocular predominantly | 49 (22.6) | 0 (0.0) | 0 (0.0) | 49 (13.5) |
| Bulbar predominantly | 4 (1.8) | 0 (0.0) | 0 (0.0) | 4 (1.1) |
| Ocular & Bulbar | 16 (7.4) | 0 (0.0) | 0 (0.0) | 16 (4.4) |
| Generalized | 148 (68.2) | 141 (100) | 6 (100) | 295 (81.0) |
| Vision | ||||
| Amblyopia | 12 (5.5) | 0 (0.0) | 0 (0.0) | 12 (3.3) |
| Ptosis at presentation | ||||
| Unilateral | 29 (13.4) | 8 (5.7) | 1 (16.7) | 38 (10.4) |
| Bilateral | 113 (52.1) | 95 (67.4) | 2 (33.3) | 210 (57.7) |
| Strabismus at presentation | ||||
| Esotropia | 21 (9.7) | 11 (7.8) | 0 (0.0) | 32 (8.8) |
| Exotropia | 15 (6.9) | 3 (2.1) | 0 (0.0) | 18 (4.9) |
| Vertical deviation | 17 (7.9) | 1 (0.7) | 0 (0.0) | 18 (4.9) |
| Strabismus, not specified | 5 (2.3) | 4 (2.8) | 0 (0.0) | 9 (2.5) |
| Limitation of (OD or OS or OU) | ||||
| Adduction | 49 (22.6) | 56 (39.7) | 0 (0.0) | 105 (28.9) |
| Abduction | 54 (24.9) | 66 (46.8) | 0 (0.0) | 120 (33.0) |
| Elevation | 44 (20.3) | 63 (44.6) | 0 (0.0) | 107 (29.4) |
| Depression | 35 (16.1) | 47 (33.3) | 0 (0.0) | 82 (22.5) |
*
Born at <37 weeks