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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.

Sasaki H, Emi M, Iijima H, Ito N, Sato H, Yabe I, Kato T, Utsumi J, Matsubara K - Mol Brain (2011)

Bottom Line: Copy number loss of SHC2 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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan. h-isasak@med.hokudai.ac.jp

ABSTRACT

Background: 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.

Results: 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 (SHC2) 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 (p = 1.04 × 10-8, odds ratio = 89.8, Pearson's chi-square test).

Conclusions: Copy number loss of SHC2 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.

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High-density custom-made tiling microarray analysis of the MZ twins discordant for the MSA phenotype. (a) Competitive hybridization of genomic DNA from the MSA-affected twin (HK33) versus that from his twin (HK34). (b) Dye-swap experiment of the normal twin (HK34) versus his affected twin (HK33). (c) Competitive hybridization of genomic DNA from the MSA-affected twin (HK33) versus that from a reference Japanese male (HapMap NA1900). (d) Competitive hybridization of genomic DNA from the MSA-affected twin (HK34) versus that from the reference Japanese male (HapMap NA19000). Each blue line represents a moving average ratio of log2 (Cy5/Cy3). The blue regions indicate deletions; these loci were defined by dye-swap experiments (red region). The top map shows the positions of putative genes in the region [16].
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Figure 3: High-density custom-made tiling microarray analysis of the MZ twins discordant for the MSA phenotype. (a) Competitive hybridization of genomic DNA from the MSA-affected twin (HK33) versus that from his twin (HK34). (b) Dye-swap experiment of the normal twin (HK34) versus his affected twin (HK33). (c) Competitive hybridization of genomic DNA from the MSA-affected twin (HK33) versus that from a reference Japanese male (HapMap NA1900). (d) Competitive hybridization of genomic DNA from the MSA-affected twin (HK34) versus that from the reference Japanese male (HapMap NA19000). Each blue line represents a moving average ratio of log2 (Cy5/Cy3). The blue regions indicate deletions; these loci were defined by dye-swap experiments (red region). The top map shows the positions of putative genes in the region [16].

Mentions: To validate the results of the CNV screening in both the affected MZ twin and 10 patients with MSA, we conducted high-density, custom-made oligonucleotide tiling microarray analysis. The DNAs from the twins were compared by competitive hybridization (Figure 3a), the hybridization results were verified by a dye-swap experiment (Figure 3b), and the DNAs were separately hybridized against a normal reference sample (HapMap NA1900; Figure 3c and 3d). We found heterozygous copy number loss (deletion) in the distal 350-kb region on the 19p subtelomere in the MSA-affected twin (HK33). The deleted region encompasses 4 genes including the (Src homology 2 domain containing)-transforming protein 2 (SHC2) gene on 19p13.3 (genomic positions 250-400).


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.

Sasaki H, Emi M, Iijima H, Ito N, Sato H, Yabe I, Kato T, Utsumi J, Matsubara K - Mol Brain (2011)

High-density custom-made tiling microarray analysis of the MZ twins discordant for the MSA phenotype. (a) Competitive hybridization of genomic DNA from the MSA-affected twin (HK33) versus that from his twin (HK34). (b) Dye-swap experiment of the normal twin (HK34) versus his affected twin (HK33). (c) Competitive hybridization of genomic DNA from the MSA-affected twin (HK33) versus that from a reference Japanese male (HapMap NA1900). (d) Competitive hybridization of genomic DNA from the MSA-affected twin (HK34) versus that from the reference Japanese male (HapMap NA19000). Each blue line represents a moving average ratio of log2 (Cy5/Cy3). The blue regions indicate deletions; these loci were defined by dye-swap experiments (red region). The top map shows the positions of putative genes in the region [16].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3141657&req=5

Figure 3: High-density custom-made tiling microarray analysis of the MZ twins discordant for the MSA phenotype. (a) Competitive hybridization of genomic DNA from the MSA-affected twin (HK33) versus that from his twin (HK34). (b) Dye-swap experiment of the normal twin (HK34) versus his affected twin (HK33). (c) Competitive hybridization of genomic DNA from the MSA-affected twin (HK33) versus that from a reference Japanese male (HapMap NA1900). (d) Competitive hybridization of genomic DNA from the MSA-affected twin (HK34) versus that from the reference Japanese male (HapMap NA19000). Each blue line represents a moving average ratio of log2 (Cy5/Cy3). The blue regions indicate deletions; these loci were defined by dye-swap experiments (red region). The top map shows the positions of putative genes in the region [16].
Mentions: To validate the results of the CNV screening in both the affected MZ twin and 10 patients with MSA, we conducted high-density, custom-made oligonucleotide tiling microarray analysis. The DNAs from the twins were compared by competitive hybridization (Figure 3a), the hybridization results were verified by a dye-swap experiment (Figure 3b), and the DNAs were separately hybridized against a normal reference sample (HapMap NA1900; Figure 3c and 3d). We found heterozygous copy number loss (deletion) in the distal 350-kb region on the 19p subtelomere in the MSA-affected twin (HK33). The deleted region encompasses 4 genes including the (Src homology 2 domain containing)-transforming protein 2 (SHC2) gene on 19p13.3 (genomic positions 250-400).

Bottom Line: Copy number loss of SHC2 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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan. h-isasak@med.hokudai.ac.jp

ABSTRACT

Background: 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.

Results: 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 (SHC2) 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 (p = 1.04 × 10-8, odds ratio = 89.8, Pearson's chi-square test).

Conclusions: Copy number loss of SHC2 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.

Show MeSH
Related in: MedlinePlus