Deletion and conversion in spinal muscular atrophy patients: Is there a relationship to severity?

✍ Scribed by Christine J. Didonato; Susan E. Ingraham; Jerry R. Mendell; Thomas W. Prior; Sharon Lenard; Richard T. Moxley III; Julaine Florence; Dr Arthur H. M. Burghes

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 787 KB
• Volume: 41
• Category: Article
• ISSN: 0364-5134
• DOI: 10.1002/ana.410410214

✦ Synopsis

The spinal muscular atrophy-determining gene, survival motor neuron (SMN), is present in two copies, telSMN and cenSMN, which can be distinguished by base-pair changes in exons 7 and 8. The telSMN gene is often absent in spinal muscular atrophy patients, which could be due to deletion or sequence conversion (telSMN conversion to cenSMN giving rise to two cenSMN genes). To test for conversion events in spinal muscular atrophy, we amplified a 1-kb fragment that spanned exons 7 and 8 of SMN from 5 patients who retained telSMN exon 8 but lacked exon 7. In all patients, sequence analysis demonstrated that cenSMN exon 7 was adjacent to telSMN exon 8, indicating conversion. All 5 patients with this mutation had type I1 or I11 spinal muscular atrophy, strongly supporting an association with From the "Department of Molecular Genetics, College of Biological Sciences. the t Deoartments o f Medical Biochemistrv, tNeurolow,