Deletion analysis of SMN and NAIP genes in Tunisian patients with spinal muscular atrophy

Background: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder involving degeneration of anterior horn cells of spinal cord, resulting in progressive muscle weakness and atrophy.

Aims: The purpose of our study was to determine the frequency of SMN and NAIP deletions in Tunisian SMA patients.

Materials and methods: Polymerase chain reaction (PCR) combined with restriction fragment length polymorphism (RFLP) was used to detect the deletion of exon 7 and exon 8 of SMN1 gene, as well as multiplex PCR for exon 5 and 13 of NAIP gene.

Results: Fifteen (45.4%) out of 33 SMA patients were homozygously deleted for exons 7 and/or 8 of SMN1. Homozygous deletion of NAIP gene was observed in 20% (3 / 15) of patients.

Conclusions: The molecular diagnosis system based on PCR-RFLP analysis can conveniently be applied in the clinical testing, genetic counseling, prenatal diagnosis, and pre-implantation genetic diagnosis of SMA.