Nelson has campaigned for screening to be rolled out after her twins were diagnosed with the condition Sign up for our free Health Check email to receive exclusive analysis on the week in health Get our free Health Check email Get our free Health Check email Email * SIGN UP I would like to be emailed about offers, events and updates from The Independent. Read our Privacy notice Hundreds more children suffering from rare muscle-wasting condition spinal muscular atrophy (SMA) are set to gain