DELETION ANALYSIS OF THE SMN AND NAIP GENES IN KUWAITI PATIENTS WITH SPINAL MUSCULAR-ATROPHY

Two genes are known to be involved in spinal muscular atrophy (SMA), n amely, SMN (survival motor neuron) and NAIP (neuronal apoptosis inhibi tory protein). Deletion analysis of these genes has been reported for many ethnic groups. We have extended this analysis to include 15 Arabi c patients (11 unrelated cases of type I, which represent practically all of the patients diagnosed within the last 2 years in Kuwait, and 4 type-II cases from a single kinship). Also, 41 healthy relatives (par ents and sibs) and 44 control individuals of Arabic origin were analyz ed. The homozygous deletions of exons 7 and 8 of the SMN gene were fou nd in all SMA patients studied. Exon 5 of NAIP was homozygously absent in all type-I patients, but was retained in type-II cases. Among memb ers of SMA families, one mother was found to be homozygously deleted f or NAIP. All of the control individuals had both normal SMN and NAIP. Our results are in agreement with the general consensus that the incid ence of NAIP deletion is higher in the more severe SMA cases. Furtherm ore, they suggest that SMA type-I chromosomes, with the dual deletion of the SMN and NAIP genes, are more common in Arabs than in patients o f other ethnic origin.