Is there a role for rare variants in DRD4 gene in the susceptibility for ADHD Searching for an effect of allelic heterogeneity
- Authors: Tovo-Rodrigues, Luciana , Rohde, Luis , Roman, Tatiana , Schmitz, Marcelo , Polanczyk, Guilherme , Zeni, Cristian , Marques, Francine , Contini, Veronica , Grevet, Eugenio , Belmonte-De-Abreu, Paulo , Bau, Claiton , Hutz, Mara
- Date: 2012
- Type: Text , Journal article
- Relation: Molecular Psychiatry Vol. 17, no. 5 (May 2012), p. 520-526
- Full Text: false
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- Description: Although several studies have demonstrated an association between the 7-repeat (7R) allele in the 48-bp variable number of tandem repeats (VNTRs) in the exon 3 at dopamine receptor D4 (DRD4) gene and attention-deficit/ hyperactivity disorder (ADHD), others failed to replicate this finding. In this study, a total of 786 individuals with ADHD were genotyped for DRD4 exon 3 VNTR. All 7R homozygous subjects were selected for VNTR re-sequencing. Subjects homozygous for the 4R allele were selected paired by age, ancestry and disorder subtypes in order to have a sample as homogeneous as possible with 7R/7R individuals. Using these criteria, 103 individuals (66 with ADHD and 37 control individuals) were further investigated. An excess of rare variants were observed in the 7R alleles of ADHD patient when compared with controls (P = 0.031). This difference was not observed in 4R allele. Furthermore, nucleotide changes that predict synonymous and non-synonymous substitutions were more common in the 7R sample (P = 0.008 for total substitutions and P = 0.043 for non-synonymous substitutions). In silico prediction of structural/functional alterations caused by these variants have also been observed. Our findings suggest that not only repeat length but also DNA sequence should be assessed to better understand the role of DRD4 exon 3 VNTR in ADHD genetic susceptibility.
- Description: C1
The epithelial sodium channel y-subunit gene and blood pressure : Family based association, renal gene expression, and physiological analyses
- Authors: Büsst, Cara , Bloomer, Lisa , Scurrah, Katrina , Ellis, Justine , Barnes, Timothy , Charchar, Fadi , Braund, Peter , Hopkins, Paul , Samani, Nilesh , Hunt, Steven , Tomaszewski, Maciej , Harrap, Stephen
- Date: 2011
- Type: Text , Journal article
- Relation: Hypertension Vol. 58, no. 6 (2011), p. 1073-1078
- Full Text: false
- Reviewed:
- Description: Variants in the gene encoding the y-subunit of the epithelial sodium channel (SCNN1G) are associated with both Mendelian and quantitative effects on blood pressure. Here, in 4 cohorts of 1611 white European families composed of a total of 8199 individuals, we undertook staged testing of candidate single-nucleotide polymorphisms for SCNN1G (supplemented with imputation based on data from the 1000 Genomes Project) followed by a meta-analysis in all of the families of the strongest candidate. We also examined relationships between the genotypes and relevant intermediate renal phenotypes, as well as expression of SCNN1G in human kidneys. We found that an intronic single-nucleotide polymorphism of SCNN1G (rs13331086) was significantly associated with age-, sex-, and body mass index-adjusted blood pressure in each of the 4 populations (P<0.05). In an inverse variance-weighted meta-analysis of this single-nucleotide polymorphism in all 4 of the populations, each additional minor allele copy was associated with a 1-mm Hg increase in systolic blood pressure and 0.52-mm Hg increase in diastolic blood pressure (SE=0.33, P=0.002 for systolic blood pressure; SE=0.21, P=0.011 for diastolic blood pressure). The same allele was also associated with higher 12-hour overnight urinary potassium excretion (P=0.04), consistent with increased epithelial sodium channel activity. Renal samples from hypertensive subjects showed a nonsignificant (P=0.07) 1.7-fold higher expression of SCNN1G compared with normotensive controls. These data provide genetic and phenotypic evidence in support of a role for a common genetic variant of SCNN1G in blood pressure determination. © 2011 American Heart Association, Inc.
Pathway analysis shows association between FGFBP1 and hypertension
- Authors: Tomaszewski, Maciej , Charchar, Fadi , Nelson, Christopher , Barnes, Timothy , Denniff, Matthew , Kaiser, Michael , Debiec, Radoslaw , Christofidou, Paraskevi , Rafelt, Suzanne , Van Harst, Pim Der , Wang, William , Maric, Christine , Zukowska-Szczechowska, Ewa , Samani, Nilesh
- Date: 2011
- Type: Text , Journal article
- Relation: Journal of the American Society of Nephrology Vol. 22, no. 5 (2011), p. 947-955
- Full Text: false
- Reviewed:
- Description: Variants in the gene encoding fibroblast growth factor 1 (FGF1) co-segregate with familial susceptibility to hypertension, and glomerular upregulation of FGF1 associates with hypertension. To investigate whether variants in other members of the FGF signaling pathway may also associate with hypertension, we genotyped 629 subjects from 207 Polish families with hypertension for 79 single nucleotide polymorphisms in eight genes of this network. Family-based analysis showed that parents transmitted the major allele of the rs16892645 polymorphism in the gene encoding FGF binding protein 1 (FGFBP1) to hypertensive offspring more frequently than expected by chance (P = 0.005). An independent cohort of 807 unrelated Polish subjects validated this association. Furthermore, compared with normotensive subjects, hypertensive subjects had approximately 1.5- and 1.4-fold higher expression of renal FGFBP1 mRNA and protein (P = 0.04 and P = 0.001), respectively. By immunohistochemistry, hypertensionrelated upregulation of FGFBP1 was most apparent in the glomerulus and juxtaglomerular space. Taken together, these data suggest that FGFBP1 associates with hypertension and that systematic analysis of signaling pathways can identify previously undescribed genetic associations. Copyright © 2011 by the American Society of Nephrology.
An NZW-derived interval on chromosome 7 moderates sialadenitis, but not insulitis in congenic nonobese diabetic mice
- Authors: Burt, Rachel , Watkins, Laura , Tan, Iris , Wang, Nancy , Quirk, Fiona , Mackin, Leanne , Morgan, Phillip , Zhang, Jian-Guo , Berzins, Stuart , Morahan, Grant , Brodnicki, Thomas
- Date: 2010
- Type: Text , Journal article
- Relation: Journal of Immunology Vol. 184, no. 2 (2010), p. 859-868
- Full Text: false
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- Description: Autoimmune lymphocytic infiltration of the salivary glands, termed sialadenitis, is a pathologic feature of Sjögren's syndrome (SjS) that is also prominent in nonobese diabetic (NOD) mice. Genetic factors regulate sialadenitis, and a previous (NOD x NZW)F2 study detected linkage to murine chromosome (Chr) 7. The locus, subsequently annotated as Ssial3, maps to the distal end of Chr7 and overlaps a region associated with type 1 diabetes susceptibility in NOD mice. To examine whether Ssial3 could contribute to both diseases, or was specific for SjS, we generated a congenic mouse strain that harbored an NZW-derived Chr7 interval on the NOD genetic background. This congenic strain exhibited reduced sialadenitis compared with NOD mice and confirmed Ssial3. This reduction, however, did not ameliorate saliva abnormalities associated with SjS-like disease in NOD mice, nor were congenic mice protected against insulitis (lymphocytic infiltration of the pancreatic islets) or diabetes onset. Thus, the Ssial3 locus appears to have a tissue-specific effect for which the NZW allele is unable to prevent other autoimmune traits in the NOD mouse. Anomalous increases for antinuclear Ab production and frequency of marginal-zone B cells were also identified in congenic mice, indicating that theNZW-derived Chr7 interval has a complex effect on the NOD immune system. Copyright © 2010 by The American Association of Immunologists, Inc.