Spinal muscular atrophy type 2
Other Names for this Disease
- Muscular atrophy, spinal, infantile chronic form
- Muscular atrophy, spinal, intermediate type
- SMA II
- Spinal muscular atrophy type II
The signs and symptoms of spinal muscular atrophy type 2 (SMA II) typically become apparent between 6 and 12 months of age, although poor muscle tone may be noticed at birth or within the first few months of life. Affected individuals may slowly gain some motor milestones, but usually do not have motor milestones beyond the ability to sit independently when placed in a sitting position. Finger trembling and general poor muscle tone are almost always present. Affected individuals generally lose the ability to sit independently by their mid-teens, on average. The life expectancy of affected individuals is not exactly known; some individuals may live into adolescence, while others may live to the third or fourth decade of life. For information about the signs and symptoms of spinal muscular atrophy in general, click here.
Last updated: 11/28/2011
- Thomas W Prior, Barry S Russman. Spinal Muscular Atrophy. GeneReviews. January 27, 2011; http://www.ncbi.nlm.nih.gov/books/NBK1352/. Accessed 11/28/2011.