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- Roshandel, Delnaz, et al.
(författare)
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A validation of the first genome-wide association study of calcaneus ultrasound parameters in the European Male Ageing Study
- 2011
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Ingår i: BMC Medical Genetics. - : Springer Science and Business Media LLC. - 1471-2350. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: A number of single nucleotide polymorphisms (SNPs) have been associated with broadband ultrasound attenuation (BUA) and speed of sound (SOS) as measured by quantitative ultrasound (QUS) at the calcaneus in the Framingham 100K genome-wide association study (GWAS) but have not been validated in independent studies. The aim of this analysis was to determine if these SNPs are associated with QUS measurements assessed in a large independent population of European middle-aged and elderly men. The association between these SNPs and bone mineral density (BMD) measured using dual-energy X-ray absorptiometry (DXA) was also tested. Methods: Men aged 40-79 years (N = 2960) were recruited from population registers in seven European centres for participation in an observational study of male ageing, the European Male Ageing Study (EMAS). QUS at the calcaneus was measured in all subjects and blood was taken for genetic analysis. Lumbar spine (LS), femoral neck (FN) and total hip (TH) BMD were measured by DXA in a subsample of 620 men in two centres. SNPs associated with BUA or SOS in the Framingham study with p < 10(-4) were selected and genotyped using SEQUENOM technology. Linear regression was used to test for the association between SNPs and standardised (SD) bone outcomes under an additive genetic model adjusting for centre. The same direction of effect and p < 0.05 indicated replication. Results: Thirty-four of 38 selected SNPs were successfully genotyped in 2377 men. Suggestive evidence of replication was observed for a single SNP, rs3754032, which was associated with a higher SOS (beta(SD) = 0.07, p = 0.032) but not BUA (beta(SD) = 0.02, p = 0.505) and is located in the 3'UTR of WDR77 (WD repeat domain 77) also known as androgen receptor cofactor p44. A single SNP, rs238358, was associated with BMD at the LS (beta(SD) = -0.22, p = 0.014), FN (beta(SD) = -0.31, p = 0.001) and TH (beta(SD) = -0.36, p = 0.002) in a locus previously associated with LS BMD in large-scale GWAS, incorporating AKAP11 and RANKL. Conclusions: We found suggestive evidence of association between a single SNP located in the 3'UTR of WDR77 with calcaneal ultrasound parameters. The majority of SNPs, associated with QUS parameters
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| 2. |
- Zheleznyakova, Galina Yu, et al.
(författare)
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Genetic and expression studies of SMN2 gene in Russian patients with spinal muscular atrophy type II and III
- 2011
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Ingår i: BMC Medical Genetics. - : Springer Science and Business Media LLC. - 1471-2350. ; 12, s. 96-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Spinal muscular atrophy (SMA type I, II and III) is an autosomal recessive neuromuscular disorder caused by mutations in the survival motor neuron gene (SMN1). SMN2 is a centromeric copy gene that has been characterized as a major modifier of SMA severity. SMA type I patients have one or two SMN2 copies while most SMA type II patients carry three SMN2 copies and SMA III patients have three or four SMN2 copies. The SMN1 gene produces a full-length transcript (FL-SMN) while SMN2 is only able to produce a small portion of the FL-SMN because of a splice mutation which results in the production of abnormal SMN Delta 7 mRNA. Methods: In this study we performed quantification of the SMN2 gene copy number in Russian patients affected by SMA type II and III (42 and 19 patients, respectively) by means of real-time PCR. Moreover, we present two families consisting of asymptomatic carriers of a homozygous absence of the SMN1 gene. We also developed a novel RT-qPCR-based assay to determine the FL-SMN/SMN Delta 7 mRNA ratio as SMA biomarker. Results: Comparison of the SMN2 copy number and clinical features revealed a significant correlation between mild clinical phenotype (SMA type III) and presence of four copies of the SMN2 gene. In both asymptomatic cases we found an increased number of SMN2 copies in the healthy carriers and a biallelic SMN1 absence. Furthermore, the novel assay revealed a difference between SMA patients and healthy controls. Conclusions: We suggest that the SMN2 gene copy quantification in SMA patients could be used as a prognostic tool for discrimination between the SMA type II and SMA type III diagnoses, whereas the FL-SMN/SMN Delta 7 mRNA ratio could be a useful biomarker for detecting changes during SMA pharmacotherapy.
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