Spinal muscular atrophy with respiratory distress type 1 associated with novel compound heterozygous mutations in IGHMBP2: Differential diagnosis in a case with congenital diaphragm eventration

摘要

Spinal muscular atrophy with respiratory distress type 1 (SMARD1, OMIM #604320) is a rare motor neuron disease caused by autosomal recessive mutations in the immunoglobulin mu binding protein 2 (IGHMBP2) gene (Grohmann et al. 2001). SMARD1 is characterized by respiratory failure requiring mechanical ventilation, initial distal and later generalized muscular weakness, and autonomic nerve dysfunction (Eckart et al. 2015). We present a case of a Japanese boy with novel compound heterozygous mutations in the IGHMBP2 gene. The patient was born to healthy non-consanguineous Japanese parents at 38 weeks gestation by normal vaginal delivery. His birth weight was 2060 g. The family history was negative for neuromuscular diseases. He manifested feeble crying at the age of 1 month. He subsequently developed respiratory distress and feeding difficulties and required mechanical ventilation by 2 months of age. Fluoroscopy showed eventration of the right hemi-diaphragm and immobility of the left hemi-diaphragm. He was diagnosed with bilateral congenital diaphragm eventration (CDE) and referred to our department. Chest X-ray showed that the right hemi-diaphragm was raised (Fig. 1a), while repeated fluoroscopy showed that the left hemi-diaphragm moved correctly on respiration. We considered his symptoms to be due to right CDE, and performed thoracoscopic plication of the right hemi-diaphragm.