Use of Tag single nucleotide polymorphisms (SNPs) to screen PTPN21: no association with Graves' disease.
ABSTRACT The protein-tyrosine-phosphate nonreceptor 22 gene (PTPN22) has recently been identified as a susceptibility locus for a number of autoimmune diseases including Graves' disease (GD). PTPN21 is another member of the PTPN family and its gene PTPN21 maps to the first reported region of genetic linkage to GD, GD-1, on chromosome 14q31. The aim of this study was to determine whether PTPN21 is acting as a GD susceptibility locus in UK Caucasian subjects.
A case control association study of seven Tag single nucleotide polymorphisms (SNPs) (rs1469602, rs8007288, rs1998670, rs11622270, rs2274736, rs2295136 and rs366476) selected to predict 51 un-genotyped polymorphisms present within PTPN21.
Unrelated Caucasian patients of UK origin with GD and ethnically and gender matched control subjects with no family history of autoimmune disease were recruited. In total, DNA was obtained from 768 GD patients and 768 control subjects.
No association of any of the seven Tag SNPs was detected with GD. Preliminary evidence of association of rs2274736 was found with younger age of GD onset (0-30 years) (OR = 1. 48 [95% CI = 1.11-1.97]). No other correlations with clinical phenotype or previously established susceptibility loci were detected.
Using a Tag SNP approach we screened PTPN21 as a susceptibility locus for GD and found no evidence for association with disease. Preliminary evidence for association of rs2274736 with younger age of GD onset requires replication in similar sized data sets to exclude a false positive result. Methods such as the Tag SNP approach significantly reduce the amount of genotyping required when screening candidate loci, including those within regions of chromosomal linkage.
- SourceAvailable from: Jannie Borst[show abstract] [hide abstract]
ABSTRACT: X-linked agammaglobulinemia (XLA) is an inherited human immunodeficiency disease, characterized by an arrest in B-cell development, which results in a dramatic decrease in immunoglobulin production. The gene product defective in XLA has been identified as a cytoplasmic protein tyrosine kinase, named Bruton's tyrosine kinase (Btk). The dramatic XLA phenotype indicates a critical role for Btk in the regulation of B-cell development. However, neither external stimuli leading to Btk activation nor any of its in vivo substrates have thus far been identified, and the mechanism of disease induction remains unexplained. We report here that stimulation of the B-cell antigen receptor (membrane immunoglobulin) on mature B-cells induces tyrosine phosphorylation of Btk in vivo, accompanied by an increase in its kinase activity in vitro. These results place Btk in the B-cell receptor signal transduction pathway, which is known to be essential in driving B-cell differentiation.Journal of Biological Chemistry 10/1994; 269(39):23857-60. · 4.65 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Autoimmune thyroid diseases (AITD), comprising Graves' disease and autoimmune hypothyroidism, are characterized by loss of immunological self-tolerance to thyroid antigens. These are complex diseases arising from a combination of genetic and environmental factors. An understanding of the genetic susceptibility factors for AITD could help to target treatments more effectively and identify people at risk for these conditions. The objective of this study was to identify regions of genetic linkage to AITD that could potentially harbor genetic susceptibility factors for these conditions. The study design was a genome-wide screen performed on affected relative pairs with AITD. Patients were recruited through hospital endocrinology clinics. Some 1119 Caucasian relative pairs affected with AITD (Graves' disease or autoimmune hypothyroidism) were recruited into the study. Blood samples were obtained from each participant for DNA analysis, and clinical questionnaires were completed. The study aimed to identify regions of genetic linkage to AITD. Three regions of suggestive linkage were obtained on chromosomes 18p11 (maximum LOD score, 2.5), 2q36 (maximum LOD score, 2.2), and 11p15 (maximum LOD score, 2.0). No linkage to human leukocyte antigen was found. The absence of significant evidence of linkage at any one locus in such a large dataset argues that genetic susceptibility to AITD reflects a number of loci, each with a modest effect. Linkage analysis may be limited in defining such loci, and large-scale association studies may prove to be more useful in identifying genetic susceptibility factors for AITD.Journal of Clinical Endocrinology & Metabolism 03/2006; 91(2):646-53. · 6.43 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: The autoimmune thyroid diseases (AITDs), comprising Graves' disease (GD) and Hashimoto's thyroiditis (HT), appear to develop as a result of a complex interaction between predisposing genes and environmental triggers. The goals of the present study were to identify the susceptibility loci for GD and HT and to study the relationships between them. We performed a whole genome linkage study on a dataset of 56 multiplex, multigenerational AITD families (354 individuals), using 387 microsatellite markers. We identified 6 loci that showed evidence for linkage to AITD. Only one locus, on chromosome 6 [AITD-1; 80 centimorgans (cM)], was linked with both GD and HT [maximum LOD score (MLS), 2.9]. This locus was close to, but distinct from, the human leukocyte antigen region. One locus on chromosome 13 (HT-1; 96 cM) was linked to HT (MLS, 2.1), and another locus on chromosome 12 (HT-2; 97 cM) was linked to HT in a subgroup of the families (MLS, 3.8). Three loci showed evidence for linkage with GD: GD-1 on chromosome 14 (99 cM; MLS, 2.5), GD-2 on chromosome 20 (56 cM; MLS, 3.5), and GD-3 on chromosome X (114 cM; MLS, 2.5). Since GD-2 showed the strongest evidence for linkage to GD we fine-mapped this locus to a 1-cM interval between markers at 55 and 56 cM on chromosome 20. These results demonstrated that 1) Graves' and Hashimoto's diseases are genetically heterogeneous, with only one locus in common to both diseases on chromosome 6; 2) only one HT locus was identified in all families, probably due to heterogeneity of the HT phenotype; and 3) three loci were shown to induce genetic susceptibility to GD by interacting with each other. One of them (GD-2) was fine-mapped to a 1-cM interval.Journal of Clinical Endocrinology & Metabolism 01/2000; 84(12):4656-64. · 6.43 Impact Factor