By Erinn Hutkin
- Type I spinal muscular atrophy (also known as Werdnig-Hoffman disease) is a severe form of the disorder that is diagnosed at birth or within the first few months of an infant’s life. Infants who have this type of spinal muscular atrophy (SMA) are developmentally delayed, so much so that most are unable to support their head or sit without help. Children with this type of SMA have breathing and swallowing problems that can lead to choking or gagging.
- Type II spinal muscular atrophy is characterized by muscle weakness that typically develops in children between 6 and 12 months old. Children with type II SMA can sit without support, but they often need help getting into a seated position. Those affected with this type of spinal muscular atrophy can’t stand or walk unless they have help.