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PubMedDate not supplied

Vogt-Koyanagi-Harada disease.

Vogt-Koyanagi-Harada disease (VKH) is a multisystem autoimmune disorder principally affecting pigmented tissues in the ocular, auditory, integumentary and central nervous systems. Patients are typically 20 to 50 years old and have no history of either surgical or accidental ocular trauma. Pigmented races are more commonly affected. Depending on revised diagnostic criteria, the disease is classified as complete, incomplete or probable based on the presence of extraocular findings (neurological, auditory and integumentary). The clinical course of VKH is divided into four phases: prodromal (mimics a viral infection), uveitic (bilateral diffuse uveitis with papillitis and exudative retinal detachment), convalescent (tissue depigmentation), and chronic recurrent (recurrent uveitis and ocular complications). The pathogenesis of VKH is thought to be related to an aberrant T cell-mediated immune response directed against self-antigens found on melanocytes. VKH has been linked to human leukocyte antigen DR4 (HLA-DR4) and HLA-Dw53, with strongest associated risk for HLA-DRB1*0405 haplotype. The diagnosis of VKH is clinical, and differential includes sympathetic ophthalmia, sarcoidosis, primary intraocular B-cell lymphoma, posterior scleritis, and uveal effusion syndrome. Treatment is typically initiated with high-dose oral corticosteroids, but other immunomondulatory agents (most oftentimes cyclosporine) may be needed for non-responsive patients or when corticosteroid side-effects are not tolerated. Visual prognosis is generally good with prompt diagnosis and aggressive immunomodulatory treatment.

Diagnosis, Differential↗
PubMed1991

Idiopathic membranous nephropathy, associated with HLA-DRw3 and not related to monocyte-phagocyte system Fc receptor dysfunction, in father and son.

Familial idiopathic membranous nephropathy, an immune-complex-associated glomerulopathy, has not been previously reported in father and son, despite its striking immunogenetic correlation, especially with HLA-DR3. As a dysfunction of the monocyte-phagocyte system (MPS), it has been observed linked to DR3 antigen, so we studied the MPS Fc receptor function in a father and his son with a histologically proven membranous nephropathy, associated with the haplotype A9-B35-DR3-DQw2. The Fc receptor function of the MPS was examined by measuring the clearance of IgG-sensitized, 51Cr-labeled erythrocytes and by measuring the ability of isolated monocytes to ingest autologous red blood cells coated with IgG anti-Rh (D) antibody. Immune clearance and in vitro phagocytosis was normal in both patients and not related to their levels of immune complexes (as measured by ELISA C1q and Conglutinin solid-phase binding assay). This report suggest that genetic factors may play an important role in the development of membranous nephropathy, and it seems not to be related to a dysfunction of MPS as measured by these tests.

Adolescent↗
PubMed1989

Assignment of autosomal dominant spinocerebellar ataxia (SCA1) centromeric to the HLA region on the short arm of chromosome 6, using multilocus linkage analysis.

A 7-generation kindred with the HLA-linked form of spinocerebellar ataxia (SCA1) was studied to determine whether the SCA1 gene maps centromeric or telomeric to the HLA loci. The DNA markers flanking the HLA-(A-B) region were used for polymorphism studies and multilocus linkage analysis. These two markers are the cDNA for the beta-subunit of HLA-DP, which is centromeric to HLA-(A-B), and the cDNA for coagulation factor XIIIa (F13A), which is telomeric to HLA-(A-B). Haplotypes were constructed using multiple polymorphisms for these two DNA markers, and pairwise linkage analysis revealed a maximum lod score of 2.18 for SCA1 versus HLA-DP at a recombination fraction of .05 and a maximum lod score of 0 for SCA1 versus F13A at a recombination fraction of .50. A possible crossover between HLA-(A-B) and HLA-DP was identified, but lack of samples from key individuals hampered the analysis. To clarify the phase and improve the analysis, the two chromosomes 6 for the crossover individual were separated in somatic cell hybrids. The results strongly favored the probability that the crossover occurred between HLA-(A-B-DR) and HLA-DP with SCA1 segregating with HLA-DP, consistent with a location centromeric to HLA-(A-B). Multilocus linkage analysis was used to evaluate further the location of SCA1 relative to F13A, HLA-(A-B), and HLA-DP; the results indicated that the SCA1 gene locus is centromeric to HLA-DP with odds of 46:1 favoring this most likely location over the second most likely location, i.e., telomeric to HLA-(A-B) between the HLA complex and F13A.

Animals↗
PubMed2001

[Prediction of insulin-dependent diabetes mellitus in children of first-degree relatives of diabetic patients].

BACKGROUND: Individuals at risk for insulin dependent diabetes mellitus (IDDM) can be identified using a combination of genetic, immunological and metabolic markers. Our study was aimed at prediction of IDDM in a cohort of children having a first-degree relative with IDDM. METHODS AND RESULTS: In the period of three years, we investigated 208 non-diabetic children and adolescents, aged 10.0 +/- 5.3 (mean +/- SD), mostly siblings of diabetic children. The genetic risk was determined by the HLA-DQB1, -DQA1 genotyping and subtyping of the DRB1*04 alleles carried on the DQB1*0302 haplotypes. Insulitis was detected using a combination of autoantibody tests against three molecular-defined antigens (insulin, GAD65, IA-2). Prevalence of insulitis (defined as confirmed positivity of at least one autoantibody) was 9/208 (4.3%). In children carrying the IDDM highest-risk genotype (HLA-DQB1*0201-DQA1*05/DQB1*0302-DQA1*03), insulitis was almost 10 times more frequent (5/24, 21%) than in children with other genotypes (4/184, 2.2%, P = 0.003). In all subjects with insulitis, the first phase insulin response (FPIR) was determined by the intravenous glucose tolerance test. Three of the nine children had decreased FPIR, of whom two were later diagnosed with IDDM. None of the remaining children developed IDDM. CONCLUSIONS: We present the first IDDM prediction study in the Czech population, emphasising the utility of genetic risk investigation in the prediction scheme.

Adolescent↗
PubMed2002

Encapsulated plasmid DNA treatment for human papillomavirus 16-associated anal dysplasia: a Phase I study of ZYC101.

High-grade dysplasia induced by high-risk types of human papillomavirus (HPV) precedes invasive cancer in anal squamous epithelium just as it does in the cervix. A therapeutic HPV vaccine strategy as a potential treatment for anal dysplasia was tested in a standard Phase I dose escalation trial. The primary objective was to evaluate the safety of the agent; additional study aims were to evaluate the histological response, immune response, and effect on anal HPV-16 infection. Each subject was treated with four i.m. injections of 50-400 microg of ZYC101 at 3-week intervals. ZYC101 is composed of plasmid DNA encapsulated in biodegradable polymer microparticles. The plasmid DNA encodes for multiple HLA-A2-restricted epitopes derived from the HPV-16 E7 protein, one of two HPV oncoproteins consistently expressed in neoplastic cells. Fifty-six potential anal dysplasia subjects were screened to identify 12 eligible subjects with HPV-16 anal infection and a HLA-A2 haplotype. The investigational agent was well tolerated in all subjects at all dose levels tested. Three subjects experienced partial histological responses, including one of three subjects receiving the 200-microg dose and two subjects at the 400-microg dose level. Using a direct Elispot, 10 of 12 subjects demonstrated increased immune response to the peptide epitopes encoded within ZYC101; each continued to show elevated immune responses 6 months after the initiation of therapy. These results support the continued investigation of a therapeutic vaccination strategy for anal dysplasia.

Adult↗
PubMed1999

Creation of a novel donor splice site in intron 1 of the factor VIII gene leads to activation of a 191 bp cryptic exon in two haemophilia A patients.

We have constructed a confidential U.K. database of haemophilia A mutations and pedigrees by characterizing the gene defect of one index patient in each U.K. family. Mutations were identified by screening all coding regions of the factor VIII (FVIII) mRNA, using solid-phase fluorescent chemical cleavage of mismatch and examining additional non-coding regions of the gene. Here we report two haemophilia A patients (UK 114 FVIII:C 2% and UK 243 FVIII:C < 1%) with an abnormal FVIII mRNA due to an A to G point mutation, 1.4 kb downstream from exon 1 in the FVIII gene. This mutation creates a new donor splice site in intron 1 and leads to insertion of a 191 bp novel exon in the mRNA. Haplotype analysis suggests that the mutation may have originated in a common ancestor of the two patients, who further illustrate how mRNA analysis allows higher efficiency of haemophilia A mutation detection, because their mutation would not have been identified by direct analysis of the factor VIII gene.

Base Sequence↗
PubMed1987

The Greek A gamma beta+-HPFH observed in a large black family.

Several members of a Black family with a heterozygosity for an A gamma beta+-HPFH, shown in 1969 to have relatively low levels of Hb F and a low glycine to alanine ratio in the gamma chain of this Hb F, were reinvestigated. Thirteen of 30 available family members in two generations had the heterozygous form of this condition, which was characterized by a decreased level of Hb A2, an average Hb FAD value of 13.3%, an equal distribution of Hb F over the red cells, and normal hematological values. The gamma chain composition of isolated Hb F was determined by reversed phase high performance liquid chromatography for all 13 heterozygotes and showed an average A gamma value of 84.5%. Hybridization with synthetic oligonucleotides, specific for normal and mutant sequences at positions 111-129 5' to the A gamma globin gene, identified a G----A base substitution at position 117, similar to that seen in subjects with the Greek A gamma-HPFH. Our data support conclusions by others that this replacement is causative of the increased A gamma chain synthesis in this condition. Haplotype analysis supported the suggestion that the G----A substitution occurred as an independent event in this Black family.

Adenine↗
PubMed1991

HLA class II sequences and genetic susceptibility to insulin dependent diabetes mellitus.

The analysis of HLA class II sequence variation in IDDM patients and controls, made possible by the PCR, has revealed that specific alleles are associated with IDDM. The HLA-DQ beta chain appears to play a role in determining genetic susceptibility and resistance, although polymorphisms in the DRB1, the DQ alpha, and the DP beta chain may also contribute. Although there is a correlation between susceptibility and the charge of DQ beta residue 57, the complex genetic epidemiology of IDDM cannot be accounted for by polymorphism at this position. As we have discussed previously (Horn et al, 1988a, 1988b; Erlich et al, 1990b), there are no unique class II sequences associated with IDDM, consistent with the view that 'normal' class II alleles confer susceptibility. Given the estimates of concordance of under 50% for monozygotic twins and approximately 15% (Tattersall and Pyke, 1972; Thomson, 1988) for HLA-identical sibs--it is not surprising that some unaffected individuals contain putative susceptibility alleles. Perhaps some environmental 'triggering' agent, such as viral infection, is required for the disease to develop in susceptible individuals. Other non-MHC-linked genes which contribute to susceptibility may account for the difference in concordance rates for monozygotic twins and for HLA-identical sibs. In the NOD (non-obese diabetic) mouse and the BB rat models for IDDM, non-MHC susceptibility loci have been identified and mapped (Colle et al, 1981; Hattori et al, 1986) but, in humans, the analysis of non-MHC candidate loci (i.e. the T cell receptor) has, thus far, failed to reveal any other susceptibility loci. In general, the HLA-linked genetic susceptibility to IDDM, as well as to other autoimmune diseases, appears to be associated with specific combinations of class II epitopes (e.g. alleles, haplotypes or genotypes) rather than with specific individual residues or epitopes. Understanding the role of these predisposing sequences will require structural analysis of the class II molecules as well as in vitro and in vivo functional studies of interactions with putative autoantigens and T cell receptors. In the meantime, DNA typing offers the potential for identifying individuals at high risk. These susceptible individuals could be monitored by immunological (e.g. anti-islet cell antibody) or by metabolic tests to detect the preclinical phase of IDDM.

Amino Acid Sequence↗
PubMed2003

Association of two polymorphisms of tumor necrosis factor gene with acute severe pancreatitis.

BACKGROUND: Acute severe pancreatitis (ASP) has an unpredictable course and outcome. Polymorphisms of the tumor necrosis factor (TNF) gene have been related to TNF production and outcome in a variety of inflammatory diseases. We assessed whether TNF gene polymorphism and plasma concentrations of TNF-alpha were related to the occurrence of ASP and septic shock from it. METHODS: The study included 208 patients (102 with ASP, 106 with acute mild pancreatitis) and 116 healthy volunteers. TNF-beta and TNF-alpha-308 polymorphisms were performed by analyzing NcoI-digested DNA fragment obtained by polymerase chain reaction (PCR). HLA-DRB1*0301 (HLA-DR3) typing was performed by sequence-specific oligonucleotide typing on PCR-amplified genomic DNA. Plasma concentrations of TNF-alpha were measured by solid-phase enzyme-amplified sensitivity immunoassay. RESULTS: The overall TNF2 allele frequency and TNFB2 allele frequency were similar in patients with mild or severe pancreatitis. Further, no significant difference in gene polymorphism frequencies was noted between patients with acute pancreatitis and controls. TNF2 frequency was significantly increased in septic shock patients compared with nonseptic shock patients (53.8 vs 22.4%; P = 0.003), as was TNFB2 frequency (88.5 vs 63.2%; P = 0.015). A linkage disequilibrium between TNF2 allele and HLA-DR3 was seen, this haplotype was not associated with severity of acute pancreatitis or outcome of septic shock in ASP patients. With regard to the mortality rate in patients who developed septic shock, those with a TNF2 allele had a significantly higher rate of mortality than those with a TNF1 allele (expired: 8 vs 1, P = 0.018). Plasma levels of TNF-alpha did not differ significantly in ASP patients displaying different alleles of the TNF gene studied. CONCLUSIONS: Results indicate that the TNF gene polymorphisms studied play no part in determination of disease severity or ASP susceptibility; however, they are both strongly related to the development of septic shock in ASP. TNF2 allele was associated with death as a result of ASP-associated septic shock.

Acute Disease↗
PubMed2003

Interleukin-10 promoter polymorphism in sporadic Alzheimer's disease.

Proinflammatory cytokines and acute-phase proteins play an important role in Alzheimer's disease (AD) neurodegeneration, and common polymorphisms of genes controlling their high production have been shown to be associated with AD. Thus, AD patients display a proinflammatory genotype and the control of inflammation might play a protective role in AD development. By sequence-specific probes, we have evaluated the role of anti-inflammatory cytokine interleukin(IL)-10 in AD, by analysing in 132 AD patients and 213 healthy controls the prevalence of three different haplotypes, involving three single-nucleotide polymorphisms (SNPs) at -1082 (G-->A), -819 (C-->T) and -592 (C-->A) nucleotides of IL-10 promoter, associated with different IL-10 production. The percentage of -1082A carrier subjects was significantly increased among AD patients, and this increase was mainly due to the increase of ATA haplotype. Analysing these results according to the well-known genetic risk factor APOE-e4 allele, no significant differences were observed in SNP IL-10 allele distribution between AD patients carrying the genotype or not. So we may conclude that the presence of -1082A allele and in particular of -1082A/-819T/-592A haplotype, associated with a low production of anti-inflammatory cytokine IL-10, may be considered as an additive and independent genetic risk factor for AD.

Alzheimer Disease↗
PubMed1979

Role of prethymic cells in acquisition of self-tolerance.

The sequential character of T-lymphocyte development as it pertains to the stage at which self-tolerance is acquired was investigated. Three phases were studied, defined here as prethymic, intrathymic, and postthymic as determined by the timing of thymus implantation. The model utilized was the temporal pattern of skin graft rejection in thymusless BALB/c nude mice implanted with allogeneic, C57BL/6J, or syngeneic thymuses before or after skin grafting; in some instances, F(1) hybrid spleen cells were also given to newborns or young adults. These experiments in nude mice showed that, (a) self-tolerance could be established despite the absence of the host's own haplotype in the implanted thymus; (b) recently emigrated postthymic cells could already discriminate self from non-self; (c) specific neonatal tolerance could be induced in nudes by inoculation of F(1) hybrid cells; (d) nudes showed a higher capacity for induction of neonatal tolerance than did normal littermates. These findings indicate that the process of self-tolerance in the T cell's lineage begins during the prethymic state early in ontogeny.

Animals↗
PubMed1999

Mutations in the gene encoding mevalonate kinase cause hyper-IgD and periodic fever syndrome. International Hyper-IgD Study Group.

Hyperimmunoglobulinaemia D and periodic fever syndrome (HIDS; MIM 260920) is a rare, apparently monogenic, autosomal recessive disorder characterized by recurrent episodes of fever accompanied with lymphadenopathy, abdominal distress, joint involvement and skin lesions. All patients have high serum IgD values (>100 U/ml) and HIDS 'attacks' are associated with an intense acute phase reaction whose exact pathophysiology remains obscure. Two other hereditary febrile disorders have been described. Familial Mediterranean fever (MIM 249100) is an autosomal recessive disorder affecting mostly populations from the Mediterranean basin and is caused by mutations in the gene MEFV (refs 5,6). Familial Hibernian fever (MIM 142680), also known as autosomal dominant familial recurrent fever, is caused by missense mutations in the gene encoding type I tumour necrosis factor receptor. Here we perform a genome-wide search to map the HIDS gene. Haplotype analysis placed the gene at 12q24 between D12S330 and D12S79. We identified the gene MVK, encoding mevalonate kinase (MK, ATP:mevalonate 5-phosphotransferase; EC 2.7.1.36), as a candidate gene. We characterized 3 missense mutations, a 92-bp loss stemming from a deletion or from exon skipping, and the absence of expression of one allele. Functional analysis demonstrated diminished MK activity in fibroblasts from HIDS patients. Our data establish MVK as the gene responsible for HIDS.

Amino Acid Sequence↗
PubMed2003

Beta 1-adrenergic receptor polymorphisms and antihypertensive response to metoprolol.

OBJECTIVES: Marked interpatient variability exists in blood pressure response to beta-blocker monotherapy. We tested the hypothesis that 2 common polymorphisms in the gene for beta(1)-adrenergic receptor are associated with antihypertensive response to metoprolol in patients with uncomplicated hypertension. METHODS: Forty hypertensive men and women aged 35 to 65 years were studied. Baseline studies included 24-hour ambulatory blood pressure monitoring. Patients took 50 mg metoprolol twice daily with weekly titration to response or 200 mg twice daily. After a minimum of 4 weeks at stable dose, treatment phase 24-hour ambulatory blood pressure monitoring was repeated. The codon 49 and 389 genotypes for beta(1)-adrenergic receptor were determined by polymerase chain reaction with restriction fragment length polymorphism. Multilinear regression was performed to determine the impact of genotype and other variables on blood pressure response to metoprolol. RESULTS: Patients homozygous for Arg at codon 389 had a nearly 3-fold greater reduction in daytime diastolic blood pressure (-13.3% +/- 8.4% versus -4.5% +/- 8.2%, P =.0018) compared with those who carried the variant allele. The haplotype pair (diplotype) for beta(1)-adrenergic receptor was also a significant predictor of response, with patients having the Ser49Arg389/Ser49Arg389 diplotype demonstrating a decline in blood pressure of 14.7 mm Hg versus 0.5 mm Hg in patients with the Gly49Arg389/Ser49Gly389 diplotype. In multiregression analysis, baseline daytime diastolic blood pressure, codon 389 genotype, and codon 49 genotype were significant predictors of blood pressure after treatment. CONCLUSIONS: Our data suggest that beta(1)-adrenergic receptor polymorphisms are important determinants of antihypertensive response to metoprolol. In the future, codon 49 and 389 genotypes or beta(1)-adrenergic receptor haplotypes might be used to predict the diastolic blood pressure response to metoprolol in patients with hypertension.

Adrenergic beta-1 Receptor Antagonists↗
PubMed1992

Linkage analysis of insulin-receptor gene in familial NIDDM.

Although non-insulin-dependent diabetes mellitus (NIDDM) is clearly inherited, the mode of inheritance and genetic etiology remain unknown. Impaired insulin action is an important component of NIDDM, which may precede NIDDM onset, and appears to be inherited. Numerous defects of the insulin-receptor gene have been described in syndromes of extreme insulin resistance, and this gene is a strong candidate for genetic predisposition to NIDDM. To test this hypothesis, we examined 18 white pedigrees from Utah that had two or more siblings with NIDDM. For each pedigree, individuals not known to be affected were tested by standard oral glucose tolerance test, and diagnoses of NIDDM and impaired glucose tolerance were made by World Health Organization criteria. Each individual was typed for seven restriction-fragment-length polymorphism markers at the insulin-receptor locus, and marker phase was established by segregation. Linkage was examined with the LINKAGE program under six models, including autosomal dominant and autosomal recessive, with individuals with impaired glucose tolerance counted either as affected or of unknown status and with or without sporadic cases of diabetes. Under each model, linkage was significantly rejected. Neither inspection of individual pedigree log of odds scores nor formal tests of heterogeneity suggested a subgroup in which linkage of NIDDM and insulin-receptor gene was likely. In addition, sharing of insulin-receptor gene haplotypes among 108 affected sibling pairs drawn from the pedigrees did not deviate from that expected by chance alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Interleukin-6: a regulator of plasma protein gene expression in hepatic and non-hepatic tissues.

The cytokine which is now called interleukin-6 (IL-6) has emerged as a major systemic alarm signal produced by essentially every injured tissue in response to almost every kind of damage. The hallmark of IL-6 gene regulation is its induction in many different tissues by inflammation-associated cytokines, bacterial products, virus infection and by activation of any of the three major signal transduction pathways (diacylglycerol, cAMP and Ca2(+)-activated). Many of these inducers act largely through a 23 base-pair "multi-response element" in the IL-6 promoter. Different tissues secrete multiple post-translationally modified forms of IL-6 (six protein species in the size range 23 to 30 kDa, and additional forms of size greater than or equal to 45 kDa). IL-6 plays a key role in activating a variety of host defence mechanisms that are aimed at limiting tissue injury. Thus, IL-6 elicits major changes in the biochemical, physiological and immunological status of the host (e.g. the "acute phase" plasma protein response). IL-6 enhances plasma protein gene expression not only in hepatocytes but also in monocytes, fibroblasts and lymphocytes. Elevated levels of IL-6 are observed in body fluids during acute and chronic infections, neoplasia and autoimmune diseases. The nature of the IL-6 receptor in hepatic and non-hepatic cells, the different signal transduction pathways involved in the regulation of particular liver genes by IL-6, the association between IL-6 levels in body fluids and clinical outcome and between IL-6 haplotypes and specific disease states remain to be explored in detail.

Animals↗
PubMed1996

Ancient DNA analysis of Fremont Amerindians of the Great Salt Lake Wetlands.

Skeletal remains of 47 individuals from the Great Salt Lake Wetlands, affiliated principally with Bear River (A.D. 400-1000) and Levee Phase (A.D. 1000-1350) Fremont cultural elements, were assessed for four mitochondrial DNA (mtDNA) markers that, in particular association, define four haplogroups (A, B, C, and D) widely shared among contemporary Amerindian groups. The most striking result is the absence of haplogroup A in this Fremont series, despite its predominance in contemporary Amerindian groups. Additionally, haplogroup B, defined by the presence of a 9bp deletion in region V, is present at the moderately high frequency of 60%. Haplogroups C and D are present at low frequencies. An additional haplotype, "N," observed in some modern populations and two other prehistoric samples, is also present in this Fremont skeletal collection.

Base Sequence↗
PubMed2001

Association of structural polymorphisms in the human period3 gene with delayed sleep phase syndrome.

Recent progress in biological clock research has facilitated genetic analysis of circadian rhythm sleep disorders, such as delayed sleep phase syndrome (DSPS) and non-24-h sleep-wake syndrome (N-24). We analyzed the human period3 (hPer3) gene, one of the human homologs of the Drosophila clock-gene period (Per), as a possible candidate for rhythm disorder susceptibility. All of the coding exons in the hPer3 gene were screened for polymorphisms by a PCR-based strategy using genomic DNA samples from sleep disorder patients and control subjects. We identified six sequence variations with amino acid changes, of which five were common and predicted four haplotypes of the hPer3 gene. One of the haplotypes was significantly associated with DSPS (Bonferroni's corrected P = 0.037; odds ratio = 7.79; 95% CI 1.59-38.3) in our study population. Our results suggest that structural polymorphisms in the hPer3 gene may be implicated in the pathogenesis of DSPS.

Adolescent↗
PubMed2001

Human sulfotransferase SULT1C1 pharmacogenetics: gene resequencing and functional genomic studies.

Sulfotransferase (SULT) enzymes catalyze an important phase II reaction in the biotransformation of many drugs and other xenobiotics. We previously cloned the human SULT1C1 cDNA and gene as steps toward pharmacogenetic studies. We have now 'resequenced' the exons, portions of introns flanking exons and approximately 315 bp of the 5' flanking region of SULT1C1 in 89 DNA samples from Caucasian subjects to identify common genetic polymorphisms. Nineteen separate polymorphisms were observed, including four nonsynonymous coding region single nucleotide polymorphisms (cSNPs) and five insertions/deletions. These data were also used to determine and/or infer common SULT1C1 haplotypes. Three of the four nonsynonymous cSNPs had allele frequencies greater than 1%, including one with a frequency of 6.7%. Expression constructs were created for all of the nonsynonymous cSNPs observed, and those constructs were used to transfect COS-1 cells. Three of the four SULT1C1 variant allozymes had significantly reduced enzyme activity when compared with the wild-type enzyme. Among the variant allozymes, apparent Km values for 3'-phosphoadenosine 5'-phosphosulfate (PAPS), the sulfate donor for the reaction, varied 7-fold, and quantitative Western blot analysis showed variable levels of immunoreactive protein when compared to the wild-type enzyme. Therefore, mechanisms responsible for decreased activity involved both alterations in levels of enzyme protein and alterations in substrate kinetics. In summary, application of a 'genotype to phenotype' strategy has resulted in the identification of a series of functionally significant common genetic polymorphisms for SULT1C1. It will now be possible to evaluate the possible contribution of these polymorphisms to variation in the sulfate conjugation of drugs, other xenobiotics and/or disease pathophysiology.

Animals↗