Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is an inherited neuromuscular condition resulting from recessive mutations in the immunoglobulin mu-binding protein (IGHMBP2) gene. Affected individuals characteristically present in infancy with progressive distal weakness and respiratory distress secondary to diaphragmatic weakness. Considerable clinical heterogeneity has been described both in its presentation and phenotype in childhood; however little data pertaining to phenotype in adulthood have been reported to date. This report describes a 21 year old woman with genetically confirmed SMARD1 who has stable muscle weakness, normal cognitive abilities and is able to lead a socially integrated lifestyle, using mechanical ventilation only overnight. This report adds new evidence for clinical variability throughout the course of SMARD1.