Patient with spinal muscular atrophy with respiratory distress type 1 presenting initially with hypertonia.

Abstract Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is a rare autosomal recessive neuromuscular disorder caused by mutations in the IGHMBP2 gene and characterized by life-threatening respiratory distress due to irreversible diaphragmatic paralysis between 6 weeks and 6 months of age. In this study, we describe a two-month-old boy who presented with hypertonia at first and developed to hypotonia progressively, which was in contrast to the manifestations reported previously. Bone tissue compromise was also observed as one of the unique symptoms. Muscle biopsy indicated mild myogenic changes. He was misdiagnosed until genetic screening to be confirmed as SMARD1. SMARD1 is a clinical heterogeneous disease and this case broadens our perception of its phenotypes.