Genotype-phenotype correlation of survival motor neuron and neuronal apoptosis inhibitory protein genes in spinal muscular atrophy patients from Iran

• Published in: Advanced biomedical research Vol. 3; no. 1; p. 74
• Main Authors: Sedghi, Maryam, Behnam, Mahdiyeh, Fazel, Esmat, Salehi, Mansoor, Ganji, Hamid, Meamar, Rokhsareh, Hosseinzadeh, Majid, Nouri, Nayereh
• Format: Journal Article
• Language: English
• Published: India Medknow Publications and Media Pvt. Ltd 2014; Medknow Publications & Media Pvt. Ltd; Medknow Publications & Media Pvt Ltd; Wolters Kluwer Medknow Publications
• Subjects: Apoptosis; Consortia; Deletion; Deoxyribonucleic acid; Development and progression; DNA; Gene mutation; Genes; Genetic aspects; Genotype & phenotype; Identification and classification; Inhibitor of apoptosis proteins; Motor neurons; Mutation; Neuromuscular diseases; neuronal apoptosis inhibitory protein gene; Original; Patient outcomes; Proteins; Rodents; severity; Spinal muscular atrophy; survival motor neuron gene; Iran; severity; Deletion; spinal muscular atrophy; neuronal apoptosis inhibitory protein gene; survival motor neuron gene
• ISSN: 2277-9175; 2277-9175
• DOI: 10.4103/2277-9175.125872

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. 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. 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). 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.