EVALUATING THE DELETION and POINT MUTATIONS OF THE SMN1 GENE IN PATIENTS WITH SPINAL MUSCULAR ATROPHY (SMA) IN WEST AZERBAIJAN PROVINCE OF IRAN

Background & Aims: Spinal muscular atrophy (SMA) is a common disorder with autosomal recessive inheritance pattern. The frequency of carriers of this disease is one in forty to one in sixty. SMA occurs in 98% of cases due to the homozygous deletion of SMN1 exons 7 and 8. The purpose of this study was to evaluating the deletion and point mutations of the SMN1 gene in patients with SMA in west Azerbaijan province of Iran. Materials & Methods: A total of 50 patients with SMA were referred to the Genetic Department after clinical diagnosis for molecular evaluation and genetic counseling. Genomic DNA was extracted from blood samples. The exclusion rate of exons 7 and 8 in the neuronal survival gene 1 was determined by using the PCR-RFLP. Results: Deletion of exons 7 and 8 were observed in 98% of the studied cases (49 out of 50 cases). In one patient, the sequencing of exon 5 showed homozygote mutation c.549 del C (p.Lys184ser fs 29) (point mutation). Conclusion: The evaluation of the presence or absence of exons 7 and 8 of the SMN1 gene, as well as point mutations in SMN1 gene in patients suspected of musculoskeletal atrophy, is effective in confirming the clinical diagnosis and subsequent genetic counseling.