Proportion of amyotrophic lateral sclerosis in the motor neuron disease spectrum (G12.20–G12.28) from 2011 to 2015
| KCD-6 code* | Classification of motor neuron diseases | 2011 N (%) | 2012 N (%) | 2013 N (%) | 2014 N (%) | 2015 N (%) |
| G12.20 | Familial motor neuron disease | 67 (2.4) | 61 (2.2) | 72 (2.4) | 67 (2.0) | 66 (1.9) |
| G12.21 | Amyotrophic lateral sclerosis | 1337 (48.2) | 1462 (52.6) | 1521 (50.4) | 1676 (50.1) | 1770 (50.0) |
| G12.22 | Primary lateral sclerosis | 46 (1.7) | 67 (2.4) | 68 (2.3) | 69 (2.1) | 92 (2.6) |
| G12.23 | Progressive bulbar palsy | 112 (4.0) | 122 (4.4) | 136 (4.5) | 186 (5.6) | 185 (5.2) |
| G12.24 | Progressive spinal muscular atrophy | 68 (2.5) | 59 (2.1) | 47 (1.6) | 55 (1.6) | 57 (1.6) |
| G12.28 | Other and unspecified motor neuron disease | 1145 (41.3) | 1011 (36.3) | 1173 (38.9) | 1293 (38.6) | 1373 (38.8) |
| Total | 2775 (100.0) | 2782 (100.0) | 3017 (100.0) | 3346 (100.0) | 3543 (100.0) |
*The KCD-6 is modified from the ICD-10.
KCD, Korean Classification of Disease.