SMN1 and proximal spinal muscular atrophy: The data showed that 10 (18.5%) SMA patients had a homozygous deletion of exon 7 in SMN1, 43 (79.6%) had a homozygous deletion of exon 7 and exon 8 in SMN1, and 1 (1.9%) had a homozygous deletion of exon 7 and exon 8 and a point mutation in SMN1. Among the patients, the majority had three (26, 53.1%) or four (20, 40.8%) copies of the SMN2 gene.