The Effects of Spinal Muscular Atrophy The effects of spinal muscular atrophy depends on what type spinal muscular atrophy your child has. Type 1 - is the most severe type of spinal muscular atrophy, symptoms tend to arise in babies less than 6 months old and they never develop the ability to sit. Respiratory problems can occur affecting life expectancy. Type 2 - is less severe than type 1 and symptoms tends to arise at around 7-18 months. The children tend to be able to sit independently and some can stand but are unlikely to be able to walk independently. Type 2 can shorten life expectancy but with improvements in care survival into adult hood is now expected. Type 3 - this is a mild type of spinal muscular atrophy and symptoms only tend to develop after 18 months but children are usually able to achieve all major milestones and can walk independently. Life expectancy usually isn't affected. Type 4 - this only occurs in adults. To book an assessment or for more information please email office@manchesterneurophysio.co.uk call 0161 883 0066 . ← Previous Physiotherapy treatment for spinal muscular atrophy Next → What is spinal muscular atrophy