Molecular diagnosis of spinal muscular atrophy in Egyptians.

This study was carried out with 33 spinal muscular atrophy (SMA) patients. DNA molecular studies of the SMA gene on the long arm of chromosome 5 (5q11.2q13.3) revealed homozygous deletion of exon 7 in 55% of cases, 36% of whom also had a homozygous delition of exon 8. The adult patients were heterozygous for an abnormal size exon 8. The remaining patients had either compound heterozygote deletion of exons 7 and 8 or were normal for both. There may therefore be 5q-unlinked SMA or SMA due to other mutations. Detection of deletions of SMA exons 7 and 8 is a powerful diagnostic test in patients with SMA, but other mutations among Egyptians must also be sought.