Mazzei, R., Conforti, F. L., Patitucci, A., Sprovieri, T., Valentino, P., Bonavita, S., Muglia, M., Gambardella, A., Magariello, A., Gabrielle, A. L., Labate, A., Bono, F., Zappia, M., and Quattrone, A.
Mazzei R, Gambardella A, Conforti FL, Magariello A, Patitucci A, Gabriele AL, Sprovieri T, Labate A, Valentino P, Bono F, Bonavita S, Zappia M, Muglia M, Quattrone A. Gene conversion events in adult-onset spinal muscular atrophy Acta Neurol Scand 2003 DOI: doinum;10.1046/j.1600-0404.2003.00181.x © Blackwell Munksgaard 2003. To investigate the possible occurrence of a conversion event in three patients with adult-onset spinal muscular atrophy (SMA) type IV, which represents the mildest form within the spectrum of the SMA phenotype. We observed three patients with adult onset SMA and apparent isolated deletion of telomeric survival motor neuron (SMN1) exon 7. To distinguish between a deletion and a sequence conversion event of exon 7, these patients were analyzed in greater detail by a simple PCR-based assay. Analysis by DdeI digestion showed products for both telomeric and centromeric copies of exon 8. These findings indicated a gene conversion event as the site for primer R111 was retained at least in one of two alleles. These results provide first evidence that a conversion event may be also associated with adult-onset SMA, and further support the notion that a gene conversion event is usually associated with a milder SMA phenotype and a later onset of disease. [ABSTRACT FROM AUTHOR]