title: Genotype-phenotype correlation of survival motor neuron and neuronal apoptosis inhibitory protein genes in spinal muscular atrophy patients from Iran.
abstract: BACKGROUND
  Proximal spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by symmetrical proximal muscle weakness and atrophy. According to the severity of the disease and the age of onset, SMA can be divided into three groups. The survival motor neuron (SMN) gene that is located on 5q13 is identified as the disease determining gene. Another gene in this region is neuronal apoptosis inhibitory protein (NAIP), and its functional role in the pathogenesis of SMA has not been fully elucidated. Here, we investigated the correlation between deletions in SMN and NAIP genes with clinical features of SMA patients.
  
  
  METHODS
  In the current study, 71 unrelated Iranian patients were investigated for the detection of deletions in SMN1 and NAIP genes. Polymerase chain reaction (PCR) was used to detect the deletions of exon 4 and 5 of the NAIP gene. Deletions in exon 7 and 8 of SMN1 gene were detected by RFLP-PCR with DraI and DdeI, respectively.
  
  
  RESULTS
  Our results showed that 51 patients have homozygous deletions in SMN1 and/or NAIP genes. Among these 51 patients, deletion in NAIP gene were found in 35 patients (65.7% of type I, 22.5% type II and 11.42% type III).
  
  
  CONCLUSIONS
  Defect in SMN1 gene plays a major role in manifesting of the disease and NAIP (4 and 5) gene acts as a modifying factor in severity of symptoms. Correlation between NAIP gene defect and severity of the disease is confirmed. However, the exact role of NAIP gene in SMA has yet to be fully clarified.
authors.affiliation: Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran ; Pediatric Inherited Disease Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Sedghi
authors.affiliation: Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mahdiyeh
authors.initials: M
authors.lastname: Behnam
authors.affiliation: Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Esmat
authors.initials: E
authors.lastname: Fazel
authors.affiliation: Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran ; Department of Genetics and Molecular Biology, Medical School, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mansoor
authors.initials: M
authors.lastname: Salehi
authors.affiliation: Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Ganji
authors.affiliation: Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Rokhsareh
authors.initials: R
authors.lastname: Meamar
authors.affiliation: Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Majid
authors.initials: M
authors.lastname: Hosseinzadeh
authors.affiliation: Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran ; Pediatric Inherited Disease Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Nayereh
authors.initials: N
authors.lastname: Nouri
keywords: Deletion; neuronal apoptosis inhibitory protein gene; severity; spinal muscular atrophy; survival motor neuron gene