Molecular analysis of the spinal muscular atrophy and neuronal apoptosis inhibitory protein genes in Saudi patients with spinal muscular atrophy

Spinal muscular atrophy [SMA] is a common, often fatal, autosomal recessive disease leading to progressive muscle wasting and paralysis as a result of degeneration of anterior horn cells of the spinal cord. The prevalence of SMA cases in the Kingdom of Saudi Arabia [KSA] is much higher than the European and North American population. Deletions or mutations in 2 genes, telomeric form of the survival motor neuron [SMN1] and the neuronal apoptosis inhibitory protein [NAIP], are known to be associated with SMA. The aim of this study is to examine the deletions or interruptions of the SMN1 and NAIP genes in Saudi patients. The study included 121 Saudi SMA patients [type I [60 patients]; type II [26 patients]; and type III [35 patients]]. The deletions or interruptions of the SMN1 and NAIP genes were detected by using polymerase chain reaction. The study was carried out at the King Fahad National Guard Hospital, Riyadh, K.S.A. between 200 and 2002. The homozygous deletions of exons 7 and 8 of the SMN1 gene were found in 94% and 87% of the patients, Exon 5 of the NAIP gene was deleted in 70%, but its deletion was more frequent in SMA type I [93%] as compared to type II [54%] and type III [43%]. Seven patients with SMA diagnosis did not show any of the above homozygous deletions. All 230 control subjects had at least one copy of both SMN1 and NAIP genes, as expected. Our results demonstrate that the deletion rate [94%] of the SMN1 gene in Saudi SMA patients is similar, irrespective of types, compared with patients of other ethnic groups. We also show that the incidence of NAIP deletion is higher in the more severe SMA cases and the dual deletion of the SMN1 and NAIP genes are more common in Saudi SMA type I patients compared with patients of other ethnic groups

Deletion mutatios in the dystrophin gene of Saudi patients with Duchenne and Becker muscular dystrophy

The deletion in the dystrophin gene has been reported for many ethnic groups, but until now the mutations in this gene have not been thoroughly investigated in Saudi patients with Duchenne muscular dystrophy [DMD] and Becker muscular dystrophy [BMD]. We examined the deletion pattern in the dystrophin gene of the Saudi patients applying multiplex-polymerase chain reaction [PCR]. The aim of this study is to describe the outcome of our initial effort to identify mutations in the dystrophin gene in a representative group of Saudi patients with DMD and BMD. Genomic deoxyribose nucleic acid was isolated from 41 patients with DMD and BMD [27 patients confirmed by muscle biopsy and 14 patients with clinical suspicion], 3 patients with limb girdle muscular dystrophy, 12 male relatives of the patients, and 5 healthy Saudi volunteers. A total of 25 exons around the deletion prone regions [hot spots] of the dystrophin gene were amplified. The study was carried out at the King Fahad National Guard Hospital, Riyadh, Kingdom of Saudi Arabia between 2000 and 2002. The deletion of one or more exons was found in 21 of 27 DMD and BMD patients confirmed by muscle biopsy. The deletion in the gene was detected in 5 of 14 patients with DMD diagnosis, but not confirmed by dystrophin staining of muscle biopsy. No deletion in the dystrophin gene was detected in control Saudi volunteers, the limb girdle dystrophy patients, and the relatives of patients, as expected. The present study suggests that intragenic dystrophin gene deletions occur with the same frequency in Saudi patients compared with other ethnic groups. The PCR-based deletion analysis provides a reasonable first step in the diagnostic care of Saudi patients who may be afflicted with DMD and BMD