Spinal muscular atrophy with respiratory distress type 1: A multicenter retrospective study.

•Spinal muscular atrophy with respiratory distress is a rare neuromuscular disease.•Progressive motor and respiratory deterioration occurs during the 1st year of life.•Premature death is common and raises ethical issues.•Phenotype is heterogeneous and can be subdivided into early-onset, classical and late-onset types.•Diagnostic criteria might need to be updated.