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- Mayans, Sofia, et al.
(författare)
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CT60 genotype does not affect CTLA-4 isoform expression despite association to T1D and AITD in northern Sweden
- 2007
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Ingår i: BMC Medical Genetics. - : Springer Science and Business Media LLC. - 1471-2350. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Polymorphisms in and around the CTLA-4 gene have previously been associated to T1D and AITD in several populations. One such single nucleotide polymorphism (SNP), CT60, has been reported to affect the expression level ratio of the soluble (sCTLA-4) to full length CTLA-4 (flCTLA-4) isoforms. The aims of our study were to replicate the association previously published by Ueda et al. of polymorphisms in the CTLA-4 region to T1D and AITD and to determine whether the CT60 polymorphism affects the expression level ratio of sCTLA-4/flCTLA-4 in our population.METHODS: Three SNPs were genotyped in 253 cases (104 AITD cases and 149 T1D cases) and 865 ethnically matched controls. Blood from 23 healthy individuals was used to quantify mRNA expression of CTLA-4 isoforms in CD4+ cells using real-time PCR. Serum from 102 cases and 59 healthy individuals was used to determine the level of sCTLA-4 protein.RESULTS: Here we show association of the MH30, CT60 and JO31 polymorphisms to T1D and AITD in northern Sweden. We also observed a higher frequency of the CT60 disease susceptible allele in our controls compared to the British, Italian and Dutch populations, which might contribute to the high frequency of T1D in Sweden. In contrast to previously published findings, however, we were unable to find differences in the sCTLA-4/flCTLA-4 expression ratio based on the CT60 genotype in 23 healthy volunteers, also from northern Sweden. Analysis of sCTLA-4 protein levels in serum showed no correlation between sCTLA-4 protein levels and disease status or CT60 genotype.CONCLUSION: Association was found between T1D/AITD and all three polymorphisms investigated. However, in contrast to previous investigations, sCTLA-4 RNA and protein expression levels did not differ based on CT60 genotype. Our results do not rule out the CT60 SNP as an important polymorphism in the development of T1D or AITD, but suggest that further investigations are necessary to elucidate the effect of the CTLA-4 region on the development of T1D and AITD.
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| 2. |
- Buxbaum, Joseph. D., et al.
(författare)
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Mutation analysis of the NSD1 gene in patients with autism spectrum disorders and macrocephaly.
- 2007
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Ingår i: BMC Medical Genetics. - : Springer Science and Business Media LLC. - 1471-2350. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: BACKGROUND: Sotos syndrome is an overgrowth syndrome characterized by macrocephaly, advanced bone age, characteristic facial features, and learning disabilities, caused by mutations or deletions of the NSD1 gene, located at 5q35. Sotos syndrome has been described in a number of patients with autism spectrum disorders, suggesting that NSD1 could be involved in other cases of autism and macrocephaly. METHODS: We screened the NSD1 gene for mutations and deletions in 88 patients with autism spectrum disorders and macrocephaly (head circumference 2 standard deviations or more above the mean). Mutation analysis was performed by direct sequencing of all exons and flanking regions. Dosage analysis of NSD1 was carried out using multiplex ligation-dependent probe amplification. RESULTS: We identified three missense variants (R604L, S822C and E1499G) in one patient each, but none is within a functional domain. In addition, segregation analysis showed that all variants were inherited from healthy parents and in two cases were also present in unaffected siblings, indicating that they are probably nonpathogenic. No partial or whole gene deletions/duplications were observed. CONCLUSIONS: Our findings suggest that Sotos syndrome is a rare cause of autism spectrum disorders and that screening for NSD1 mutations and deletions in patients with autism and macrocephaly is not warranted in the absence of other features of Sotos syndrome.
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| 3. |
- Kathiresan, Sekar, et al.
(författare)
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A genome-wide association study for blood lipid phenotypes in the Framingham Heart Study
- 2007
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Ingår i: BMC Medical Genetics. - 1471-2350. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Blood lipid levels including low-density lipoprotein cholesterol ( LDL-C), high-density lipoprotein cholesterol ( HDL-C), and triglycerides ( TG) are highly heritable. Genome-wide association is a promising approach to map genetic loci related to these heritable phenotypes. Methods: In 1087 Framingham Heart Study Offspring cohort participants ( mean age 47 years, 52% women), we conducted genome-wide analyses ( Affymetrix 100K GeneChip) for fasting blood lipid traits. Total cholesterol, HDL-C, and TG were measured by standard enzymatic methods and LDL-C was calculated using the Friedewald formula. The long-term averages of up to seven measurements of LDL-C, HDL-C, and TG over a similar to 30 year span were the primary phenotypes. We used generalized estimating equations ( GEE), family-based association tests ( FBAT) and variance components linkage to investigate the relationships between SNPs ( on autosomes, with minor allele frequency >= 10%, genotypic call rate >= 80%, and Hardy-Weinberg equilibrium p >= 0.001) and multivariable-adjusted residuals. We pursued a three-stage replication strategy of the GEE association results with 287 SNPs ( P < 0.001 in Stage I) tested in Stage II ( n similar to 1450 individuals) and 40 SNPs ( P < 0.001 in joint analysis of Stages I and II) tested in Stage III ( n similar to 6650 individuals). Results: Long-term averages of LDL-C, HDL-C, and TG were highly heritable ( h(2) = 0.66, 0.69, 0.58, respectively; each P < 0.0001). Of 70,987 tests for each of the phenotypes, two SNPs had p < 10(-5) in GEE results for LDL-C, four for HDL-C, and one for TG. For each multivariable-adjusted phenotype, the number of SNPs with association p < 10(-4) ranged from 13 to 18 and with p < 10(-3), from 94 to 149. Some results confirmed previously reported associations with candidate genes including variation in the lipoprotein lipase gene ( LPL) and HDL-C and TG ( rs7007797; P = 0.0005 for HDL-C and 0.002 for TG). The full set of GEE, FBAT and linkage results are posted at the database of Genotype and Phenotype (dbGaP). After three stages of replication, there was no convincing statistical evidence for association ( i.e., combined P < 10(-5) across all three stages) between any of the tested SNPs and lipid phenotypes. Conclusion: Using a 100K genome-wide scan, we have generated a set of putative associations for common sequence variants and lipid phenotypes. Validation of selected hypotheses in additional samples did not identify any new loci underlying variability in blood lipids. Lack of replication may be due to inadequate statistical power to detect modest quantitative trait locus effects ( i.e., < 1% of trait variance explained) or reduced genomic coverage of the 100K array. GWAS in FHS using a denser genome-wide genotyping platform and a better-powered replication strategy may identify novel loci underlying blood lipids.
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