Résumé :
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Introduction: Spinal muscular atrophy (SMA) is one of the most common autosomal recessive disorders, characterized by degeneration of anterior horn cells in the spinal cord, and leads to progressive muscular weakness and atrophy In the present study, to elucidate the correlation between genotype and clinical severity in SMA patients, we analyzed the molecular genetic features of 57 Algerian patients with SMA, from 38 unrelated Patients and methods: All patients fulfilled the diagnostic criteria of SMA as defined by the International SMA Consortium. Deletions of exons 7 and 8 of the SMN gene were analysed by an enzyme digestion assay as described by van der Steege and al NAIP gene analysis was performed by PCR amplification of exon 4 and 5 as described by Roy et al Results and Discussion : The patients were classified into SMA type-I (09 patients), type-II (11 patients), and type-III (37 patients) 37 of the 57 SMA patients (64,9%), were homozygous for deletion of SMN1 exon 7 and 8 (13 type I, 10 type II and 14 type III).). We did not find any correlation between the SMN1 deletion and clinical severity of SMA NAIP exon 4 and 5 was deleted in 16 of 57 SMA patients (09 type I, 05 type II, 02 type III In all patients with a deletion of NAIP exon 4 and 5, there was also a deletion of SMN1 exon 7. Frequency of NAIP deletions was significantly higher in type I patients than in type II or III patients. 07 type I patients died or required artificial respiratory before the age of 6 months, among these seven patients, 5 lacked the NAIP gene Conclusion: Deletion of the NAIP gene is closely related to the clinical severity of SMA, while the deletion of SMN1 does not correlate with clinical severity.
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