Copy number loss of (src homology 2 domain containing)-transforming protein 2 (SHC2) gene: discordant loss in monozygotic twins and frequent loss in patients with multiple system atrophy
<p>Abstract</p> <p>Background</p> <p>Multiple system atrophy (MSA) is a sporadic disease. Its pathogenesis may involve multiple genetic and nongenetic factors, but its etiology remains largely unknown. We hypothesized that the genome of a patient with MSA would demonstrate copy number variations (CNVs) in the genes or genomic regions of interest. To identify genomic alterations increasing the risk for MSA, we examined a pair of monozygotic (MZ) twins discordant for the MSA phenotype and 32 patients with MSA.</p> <p>Results</p> <p>By whole-genome CNV analysis using a combination of CNV beadchip and comparative genomic hybridization (CGH)-based CNV microarrays followed by region-targeting, high-density, custom-made oligonucleotide tiling microarray analysis, we identified disease-specific copy number loss of the (Src homology 2 domain containing)-transforming protein 2 (<it>SHC2</it>) gene in the distal 350-kb subtelomeric region of 19p13.3 in the affected MZ twin and 10 of the 31 patients with MSA but not in 2 independent control populations (<it>p </it>= 1.04 × 10<sup>-8</sup>, odds ratio = 89.8, Pearson's chi-square test).</p> <p>Conclusions</p> <p>Copy number loss of <it>SHC2 </it>strongly indicates a causal link to MSA. CNV analysis of phenotypically discordant MZ twins is a powerful tool for identifying disease-predisposing loci. Our results would enable the identification of novel diagnostic measure, therapeutic targets and better understanding of the etiology of MSA.</p
