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B Vaidya

Publications and source records attributed to B Vaidya.

At least 19 recordsLinked to original sources
PubMed2006

Influences of age, gender, smoking, and family history on autoimmune thyroid disease phenotype.

CONTEXT: Both genetic and environmental factors contribute to susceptibility to Graves' disease (GD) and Hashimoto's thyroiditis (HT), as well as disease manifestations. OBJECTIVE: The objective of the study was to define how endogenous/environmental factors contribute to variation in phenotype. DESIGN/SETTING: This was a multicenter cohort study. PATIENTS/OUTCOME MEASURES: We prospectively collected clinical/biochemical data as part of the protocol for a United Kingdom DNA collection for GD and HT. We investigated, in 2805 Caucasian subjects, whether age at diagnosis, gender, family history (FH), smoking history, and presence of goiter influenced disease manifestations. RESULTS: For 2405 subjects with GD, the presence of goiter was independently associated with disease severity (serum free T4 at diagnosis) (P < 0.001). Free T4 (P < 0.05) and current smoking (P < 0.001) were both independent predictors of the presence of ophthalmopathy. Approximately half of those with GD (47.4% of females, 40.0% of males) and HT (n = 400) (56.4% of females, 51.7% of males) reported a FH of thyroid dysfunction. In GD, a FH of hyperthyroidism in any relative was more frequent than hypothyroidism (30.1 vs. 24.4% in affected females, P < 0.001). In HT, a FH of hypothyroidism was more common than hyperthyroidism (42.1 vs. 22.8% in affected females, P < 0.001). For GD (P < 0.001) and HT (P < 0.05), a FH was more common in maternal than paternal relatives. The reporting of a parent with thyroid dysfunction (hyper or hypo) was associated with lower median age at diagnosis of both GD (mother with hyperthyroidism, P < 0.001) and HT (father with hypothyroidism, P < 0.05). In GD and HT, there was an inverse relationship between the number of relatives with thyroid dysfunction and age at diagnosis (P < 0.01). CONCLUSIONS: Marked associations among age at diagnosis, disease severity, goiter, ophthalmopathy, smoking, and FH provide evidence for interactions between genetic and environmental/endogenous factors; understanding these may allow preventive measures or better tailoring of therapies.

Adolescent↗
PubMed2006

GAD antibodies in probands and their relatives in a cohort clinically selected for Type 2 diabetes.

AIMS: A subset of patients who present as if they have Type 2 diabetes have positive pancreatic autoantibodies, and have been referred to as having latent autoimmune diabetes in adults (LADA). We assessed the prevalence and clinical characteristics of patients with glutamic acid decarboxylase antibodies (GADA) in a cohort clinically selected for Type 2 diabetes and determined the presence of diabetes and GADA in their first-degree relatives. METHODS: GADA were measured in 2059 subjects, not known to be related, and clinically selected as having Type 2 diabetes for genetic studies. Clinical characteristics were compared in GADA positive and GADA negative subjects. Diabetes and GAD antibody status were compared in 208 first-degree relatives of GADA positive and GADA negative probands. RESULTS: Of the subjects, 136 (7%) were GADA positive. Compared with the GADA negative subjects, they were slimmer (P < 0.001), diagnosed at a younger age (P = 0.011) and progressed to insulin faster (P < 0.001). Thirty-three per cent of GADA positive subjects had a first-degree relative with diabetes compared with 42% of GADA negative subjects (P = 0.034). The overall prevalence of GADA was similar in the first-degree relatives of GADA positive and GADA negative probands (4 v 5%), and 19 of 22 (86%) diabetic relatives of GADA positive probands were GADA negative. CONCLUSION: Despite clinically selecting a Type 2 diabetes cohort, 7% were GADA positive with an altered phenotype. These GADA positive patients had a strong family history of non-autoimmune diabetes. This suggests that, in this subgroup of patients, autoimmune pancreatic beta-cell destruction occurs on a background of Type 2 diabetes genetic susceptibility.

Adult↗
PubMed2005

Detection of an MEN1 gene mutation depends on clinical features and supports current referral criteria for diagnostic molecular genetic testing.

OBJECTIVE: Diagnostic molecular genetic testing for multiple endocrine neoplasia type 1 (MEN1) has been available since the identification of the MEN1 gene in 1997. Mutation screening of the MEN1 gene has been recommended for patients who meet clinical criteria for MEN1 (at least two of the following: parathyroid hyperplasia, pancreatic endocrine tumour or pituitary adenoma) and those in whom a diagnosis of MEN1 is suspected. We examined the appropriateness of these clinical criteria. PATIENTS AND METHODS: A total of 292 patients were referred for diagnostic testing. The coding region of the MEN1 gene was sequenced in 186 index cases and mutation testing was requested for 106 subjects, including 83 asymptomatic relatives. RESULTS: MEN1 gene mutations were identified in 68/186 index cases (37%). Twenty-nine of the 60 MEN1 mutations reported are novel. The likelihood of finding a mutation was correlated with the number of MEN1-related tumours (mutation detection rate of 79%, 37% and 15% in patients with three, two and one main MEN1-related tumours; P < or = 0.00001) and increased in the presence of a family history (mutation detection rate of 91%, 69% and 29%vs. 69%, 23% and 0% in sporadic cases with three, two or one main MEN1-related tumours, respectively; P < or = 0.00001). The pick-up rate in the 83% of subjects who met proposed criteria for diagnostic testing was 42%, but in those who did not meet these criteria this fell to 0%. CONCLUSIONS: The likelihood of finding an MEN1 mutation depends on the clinical features of the patient and their family. This large series supports present referral criteria for diagnostic mutation screening, but suggests that patients with sporadic isolated tumours rarely have MEN1 mutations.

Adolescent↗
PubMed2003

CTLA4 gene and Graves' disease: association of Graves' disease with the CTLA4 exon 1 and intron 1 polymorphisms, but not with the promoter polymorphism.

OBJECTIVE: Recent studies have shown that Graves' disease (GD) is linked to and associated with alleles of the cytotoxic T lymphocyte antigen-4 (CTLA4) locus. However, the true pathogenic polymorphism(s) at this locus remains uncertain. Moreover, the association studies of the promoter CTLA4(-318)C/T polymorphism in white GD populations have produced conflicting results. Therefore, we have analysed three CTLA4 single nucleotide polymorphisms, including promoter CTLA4(-318)C/T, exon 1 CTLA4(49)A/G and intron 1 CTLA4(1822)C/T in our GD cohort from the UK. PATIENTS AND METHODS: We studied 301 white patients with GD and 349 healthy ethnically matched local controls. Amongst GD probands, 129 had significant thyroid-associated orbitopathy (TAO; NOSPECS class III or worse). The CTLA4(-318)C/T, CTLA4(49)A/G and CTLA4(1822)C/T polymorphisms were genotyped by using the restriction enzymes MseI, Bst71I and HaeIII, respectively. RESULTS: We found no association between GD and alleles of CTLA4(-318)C/T. GD was found to be associated with the G allele of CTLA4(49)A/G[P = 5.9 x 10(-6), odds ratio (OR) 1.65] and the T allele of CTLA4(1822)C/T (P = 7.7 x 10(-6), OR 1.64). The frequencies of these alleles were significantly higher in GD probands with significant TAO than in those without TAO (G allele: P = 0.001, OR 1.68; T allele: P = 0.001, OR 1.70). CONCLUSIONS: The promoter CTLA4(-318)C/T polymorphism is not in linkage disequilibrium with the pathogenic polymorphism(s) at the CTLA4 locus. The alleles of both the exon 1 CTLA4(49)A/G and the intron 1 CTLA4(1822)C/T polymorphisms are associated with GD, which is stronger in patients with TAO.

Abatacept↗
PubMed2002

An association between the CTLA4 exon 1 polymorphism and early rheumatoid arthritis with autoimmune endocrinopathies.

OBJECTIVE: To examine the allelic association of the single nucleotide polymorphism (CTLA4A/G) in exon 1 of the cytotoxic T lymphocyte antigen-4 (CTLA4) gene with early rheumatoid arthritis (RA). METHODS: One hundred and twenty-three unrelated white probands with early RA from the north-east of England and 349 local ethnically matched controls were studied. The CTLA4A/G polymorphism was genotyped with a polymerase chain reaction (PCR) method and digestion with the restriction enzyme Bst71I. Probands were also screened by allele-specific PCR for alleles HLA DRB1*01 and DRB1*04. RESULTS: The frequency of the G allele at CTLA4A/G was significantly increased in probands with early RA compared with controls [43 vs 36%; P=0.028, odds ratio (OR) 1.35, 95% confidence interval (CI) 1.01-1.82]. Most of this increased frequency was attributable to RA individuals with coexisting autoimmune thyroid disease or type 1 diabetes (58 vs 36% in controls; P=0.005, OR 2.50, CI 1.29-4.84). The frequency of the G allele in RA patients without autoimmune endocrinopathy was 40%, which was not significantly different from that in controls (P=0.140). CONCLUSION: The association between the CTLA4 G allele and early RA is largely explained by individuals with RA who have coexisting autoimmune endocrinopathies.

Abatacept↗
PubMed2001

Insulin-like growth factor-1 induces survival and growth of biologically early melanoma cells through both the mitogen-activated protein kinase and beta-catenin pathways.

Melanoma cells produce growth factors for autocrine growth control and for stimulating fibroblasts and endothelial cells in the tumor stroma. Activated stromal fibroblasts can in turn secrete growth factors that support tumor growth. We studied this feedback from fibroblasts to melanoma cells by overexpressing insulin-like growth factor 1 (IGF-1) with an adenoviral vector. Melanoma cells do not produce IGF-1. IGF-1 enhanced survival, migration, and growth of cells from biologically early lesions, but not from biologically late primary or metastatic lesions. Early melanoma cells were activated by IGF-1 to phosphorylate Erk1 and -2 of the mitogen-activated protein kinase pathway. IGF-1 also activated Akt, inhibited its down-stream effector GSK3-beta, and stabilized beta-catenin. Late primary and metastatic melanoma cells did not respond to growth stimulation by IGF-1 because of a constitutive activation of the mitogen-activated protein kinase pathway and a higher level of stabilized beta-catenin. These studies demonstrate that fibroblast-derived growth factors from the tumor environment can provide the malignant cells with a positive feedback through multiple mechanisms but that this stimulation is required only for cells from early and not late stages of tumor progression.

Cell Division↗
PubMed2001

Evidence for a Graves' disease susceptibility locus at chromosome Xp11 in a United Kingdom population.

Graves' disease (GD), which has a strong female preponderance (female/male ratio, >5:1), is inherited as a complex genetic trait. Loci for GD have started to be defined using genome-wide approaches for genetic linkage. To date, 3 loci have been confirmed in at least 2 cohorts of GD patients, the strongest effect being at the cytotoxic T lymphocyte antigen-4 (CTLA-4) locus on chromosome 2q33 in our population. Two other loci for GD have recently been proposed, but not confirmed, on chromosomes Xq21 (GD3) and 14q31 (GD1). We studied a cohort of 75 sibling pairs with GD from the United Kingdom for linkage to 12 markers over a 83-cM region of the X chromosome and for 8 markers over a 36-cM region of 14q31-q33. A peak multipoint nonparametric linkage score of 2.21 (P = 0.014) was found at marker DXS8083 on Xp11, which increased to a nonparametric linkage score of 3.18 (P = 0.001) in data that had been conditioned for allele sharing at the CTLA-4 locus under an epistatic model. There was no evidence to support linkage of GD to Xq21.33-q22 (GD3) or at the 14q31-q33 (GD1) region in our population. A locus with a moderate contribution to GD susceptibility (lambda(s) = 1.4) is likely to exist in the Xp11 region, but we are unable to confirm that the GD1 or the GD3 regions contain major susceptibility loci in our United Kingdom GD population.

Abatacept↗
PubMed2000

Evidence for a new Graves disease susceptibility locus at chromosome 18q21.

Graves disease (GD) is a common autoimmune thyroid disorder that is inherited as a complex multigenic trait. By using a single microsatellite marker at each locus, we screened the type 1 diabetes loci IDDM4, IDDM5, IDDM6, IDDM8, and IDDM10 and the fucosyltransferase-2 locus for linkage in sib pairs with GD. This showed a two-point nonparametric linkage (NPL) score of 1.57 (P=.06) at the IDDM6 marker D18S41, but NPL scores were <1.0 at the other five loci. Thus, the investigation of the IDDM6 locus was extended by genotyping 11 microsatellite markers spanning 48 cM across chromosome 18q12-q22 in 81 sib pairs affected with autoimmune thyroid disease (AITD). Multipoint analysis, designating all AITD sib pairs as affected, showed a peak NPL score of 3.46 (P=.0003), at the marker D18S487. Designation of only GD cases as affected (74 sib pairs) showed a peak NPL score of 3.09 (P=.001). Linkage to this region has been demonstrated in type 1 diabetes (IDDM6), rheumatoid arthritis, and systemic lupus erythematosus, which suggests that this locus may have a role in several forms of autoimmunity.

Alleles↗
PubMed2000

CTLA-4 gene polymorphism confers susceptibility to primary biliary cirrhosis.

BACKGROUND/AIM: Primary biliary cirrhosis (PBC) is an autoimmune cholestatic liver disease thought to develop through a complex interaction of genetic and environmental factors. It is characterised by T-cell-mediated non-suppurative destructive cholangitis. We have studied the polymorphic cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) gene, which encodes a molecule that is a vital negative regulator of T-cell activation, as a candidate susceptibility locus for PBC. This gene on chromosome 2q33 (designated IDDM12) is associated with susceptibility to both type 1 diabetes and autoimmune thyroid disease. METHODS: The CTLA-4 exon 1 polymorphism (A/G encoding for threonine or alanine, respectively) was genotyped via polymerase chain reaction in 200 Caucasoid PBC patients and 200 non-related geographically matched Caucasoid controls. RESULTS: There was significant overrepresentation of the G/A and G/G genotypes in PBC patients compared to controls (G/A 53% vs 40%; G/G 18.5% vs 10.5%, Odds Ratio (OR)=2.45 [95% CI 1.6-3.7], p=0.00006, chi2=19.4). Likewise, there was a significant difference in allele frequencies (G encoding alanine at codon 17, PBC 0.45 vs controls 0.305: OR=1.9 [1.4-2.5], p<0.0002). This association remained significant (p=0.00027) when patients with autoimmune thyroid disease were excluded from the analysis. CONCLUSIONS: The CTLA-4 exon 1 polymorphism is the first non-major histocompatibility complex gene to be identified as a susceptibility locus for PBC. Our data support the hypothesis that clinically distinct autoimmune disease may be controlled by a common set of susceptibility genes.

Abatacept↗
PubMed2000

Association analysis of the cytotoxic T lymphocyte antigen-4 (CTLA-4) and autoimmune regulator-1 (AIRE-1) genes in sporadic autoimmune Addison's disease.

Although autoimmune Addison's disease (AAD) may occur as a component of the monogenic autoimmune polyendocrinopathy type 1 syndrome (APS1), it is most commonly found as an isolated disorder or associated with the autoimmune polyendocrinopathy type 2 syndrome (APS2). It is likely that sporadic (non-APS1) AAD is inherited as a complex trait; however, apart from the major histocompatibility complex, the susceptibility genes remain unknown. We have examined polymorphisms at two non-major histocompatibility complex candidate susceptibility loci in sporadic (non-APS1) AAD: the cytotoxic T lymphocyte antigen-4 (CTLA-4) gene and the autoimmune regulator (AIRE-1) gene. DNA samples from AAD subjects (n = 90) and local controls (n = 144 for CTLA-4; n = 576 for AIRE-1) were analyzed for the CTLA-4A/G polymorphism in exon 1 of the CTLA-4 gene and for the common mutant AIRE-1 allele (964de113) in United Kingdom subjects with APS1, by using the restriction enzymes Bst7II and BsrBI, respectively. There was an association of the G allele at CTLA-4A/G in AAD subjects (P = 0.008 vs. controls), which was stronger in subjects with AAD as a component of APS2 than in subjects with isolated AAD. In contrast, the mutant AIRE-1 964del13 allele was carried in one each of the 576 (0.2%) control subjects and the 90 (1.1%) AAD subjects as a heterozygote (P = 0.254, not significant), suggesting that this common AIRE-1 gene abnormality does not have a major role in sporadic (non-APS1) AAD.

Abatacept↗
PubMed1999

The cytotoxic T lymphocyte antigen-4 is a major Graves' disease locus.

Graves' disease (GD) is an autoimmune thyroid disorder that is inherited as a complex trait. We have genotyped 77 affected sib-pairs with autoimmune thyroid disease for eight polymorphic markers spanning the cytotoxic T lymphocyte antigen-4 ( CTLA-4 ) region of chromosome 2q31-q33, and for five markers spanning the major histocompatibility complex ( MHC ) region of chromosome 6p21. Non-parametric analysis showed linkage of GD to the CTLA-4 region with a peak non-parametric linkage (NPL) score of 3.43 ( P = 0.0004) at the marker D2S117. The proportion of affected full-sibs sharing zero alleles (z0) reached a minimum of 0.113 close to D2S117, giving a locus-specific lambdas for this region of 2.2. Families with brother-sister sib-pairs showed a peak NPL of 3.46 ( P = 0.0003, lambdas > 10) at D2S117, compared with 2.00 ( P = 0.02, lambdas = 1.9) in the families with only affected females, suggesting a stronger influence in families with affected males. Association between GD and the G allele of the Thr17Ala polymorphism within the CTLA-4 gene ( CTLA4A/G ) was observed using unaffected sib controls ( P = 0.005). Lesser evidence for linkage was found at the MHC locus, with a peak NPL score of 1.95 ( P = 0.026), between the markers D6S273 and TNFalpha. We demonstrate that the CTLA-4 locus (lambdas = 2.2) and the MHC locus (lambdas = 1.6) together confer approximately 50% of the inherited susceptibility to GD disease in our population.

Abatacept↗
PubMed1999

Concurrence of Pendred syndrome, autoimmune thyroiditis, and simple goiter in one family.

Pendred syndrome is the autosomal recessively transmitted association of familial goiter and congenital deafness. There is no specific biochemical marker of this disease, and the diagnosis depends upon the demonstration of the triad of congenital sensorineural hearing loss, goiter, and abnormal perchlorate discharge test. Pendred syndrome is caused by mutations within the putative ion transporter gene (PDS gene), located on chromosome 7q. A wide variation in the clinical presentation of this condition, and its well documented phenotypic overlap with other thyroid disorders (such as Hashimoto's thyroiditis), can lead to diagnostic difficulties. The potential for misdiagnosis increases when these disorders occur coincidentally in the same family. We describe a kindred in which Pendred syndrome, autoimmune thyroiditis, and simple goiter coexisted, to highlight these diagnostic pitfalls and to illustrate the use of mutational analysis in resolving diagnostic confusion.

Adult↗
PubMed1998

A common and recurrent 13-bp deletion in the autoimmune regulator gene in British kindreds with autoimmune polyendocrinopathy type 1.

Autoimmune polyendocrinopathy type 1 (APS1) is an autosomal recessive disorder characterized by autoimmune hypoparathyroidism, autoimmune adrenocortical failure, and mucocutaneous candidiasis. Recently, an autoimmune regulator gene (AIRE-1), which is located on chromosome 21q22.3, has been identified, and mutations in European kindreds with APS1 have been described. We used SSCP analysis and direct DNA sequencing to screen the entire 1,635-bp coding region of AIRE-1 in 12 British families with APS1. A 13-bp deletion (964del13) was found to account for 17 of the 24 possible mutant AIRE-1 alleles, in our kindreds. This mutation was found to occur de novo in one affected subject. A common haplotype spanning the AIRE-1 locus was found in chromosomes that carried the 964del13 mutation, suggesting a founder effect in our population. One of 576 normal subjects was also a heterozygous carrier of the 964del13 mutation. Six other point mutations were found in AIRE-1, including two 1-bp deletions, three missense mutations (R15L, L28P, and Y90C), and a nonsense mutation (R257*). The high frequency of the 964del13 allele and the clustering of the other AIRE-1 mutations may allow rapid molecular screening for APS1 in British kindreds. Furthermore, the prevalence of the 964del13 AIRE-1 mutation may have implications in the pathogenesis of the more common autoimmune endocrinopathies in our population.

Alleles↗