Table 1 Clinical classification criteria for spinal muscular atrophy
From: Spinal muscular atrophy
| Â | Age of onset | Highest function achieved |
|---|---|---|
Type I (Werdnig-Hoffmann disease) | 0-6 months | Never sit |
Type II (intermediate) | 7-18 months | Sit never stand |
Type III (mild, Kugelberg-Welander disease) in adulthood | > 18 months | Stand and Walk during aldulthood |
Type IV (adult) | 2°-3° decade | Walk unaided |