title: Infantile spinal muscular atrophy with respiratory distress type I presenting without respiratory involvement: Novel mutations and review of the literature.
abstract: Spinal muscular atrophy with respiratory distress type 1 (SMARD1), also known as distal spinal muscular atrophy 1 (DSMA1) or distal hereditary motor neuropathies type 6 (dHMN6), is a rare autosomal recessive motor neuron disorder that affects infants and is characterized by diaphragmatic palsy, distal muscular weakness and muscle atrophy. The disease is caused by mutations in the gene encoding immunoglobulinm-binding protein 2 (IGHMBP2). We present a female child with novel compound heterozygous mutations in IGHMBP2 gene c.344C>T (p.115T>M) and c.1737C>A (p.579F>L), displaying distal limbs weakness and atrophy without signs of diaphragmatic palsy or respiratory insufficiency. We review 20 reported SMARD1 cases that have no respiratory involvement or have late onsets. We propose that IGHMBP2 gene mutations are characterized by significant phenotypic heterogeneity. Diaphragmatic palsy and respiratory distress may be absent and SMARD1 should be considered in infantile with the onset of peripheral neuropathies.
authors.affiliation: Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai JiaoTong University School of Medicine, Shanghai, China.
authors.forename: Xinghua
authors.initials: X
authors.lastname: Luan
authors.affiliation: Department of Neurology and Institute of Neurology, Ruijin Hospital North Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Huang
authors.affiliation: Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai JiaoTong University School of Medicine, Shanghai, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai JiaoTong University School of Medicine, Shanghai, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai JiaoTong University School of Medicine, Shanghai, China. Electronic address: chen_sd@medmail.com.cn.
authors.forename: Shengdi
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai JiaoTong University School of Medicine, Shanghai, China. Electronic address: caoli2000@yeah.net.
authors.forename: Li
authors.initials: L
authors.lastname: Cao
mesh_terms: D017668:Age of Onset; D002675:Child, Preschool; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D006801:Humans; D009134:Muscular Atrophy, Spinal / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology*; D009154:Mutation; D012127:Respiratory Distress Syndrome, Newborn / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology*; D012131:Respiratory Insufficiency / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; C489892:IGHMBP2 protein, human; D014157:Transcription Factors
keywords: Diaphragmatic palsy; IGHMBP2; Peripheral neuropathy; Respiratory involvement; Spinal muscular atrophy with respiratory distress type 1 (SMARD1)