Showing papers by "Wellcome Trust Centre for Human Genetics published in 1998"
TL;DR: It is shown that hypoxia and hypoglycaemia reduce proliferation and increase apoptosis in wild-type (Hif-1α+/+) embryonic stem (ES) cells, but not in ES cells with inactivated HIF-1 α genes (HIF- 1α−/−), suggesting that there are at least two different adaptive responses to being deprived of oxygen and nutrients.
Abstract: As a result of deprivation of oxygen (hypoxia) and nutrients, the growth and viability of cells is reduced. Hypoxia-inducible factor (HIF)-1alpha helps to restore oxygen homeostasis by inducing glycolysis, erythropoiesis and angiogenesis. Here we show that hypoxia and hypoglycaemia reduce proliferation and increase apoptosis in wild-type (HIF-1alpha+/+) embryonic stem (ES) cells, but not in ES cells with inactivated HIF-1alpha genes (HIF-1alpha-/-); however, a deficiency of HIF-1alpha does not affect apoptosis induced by cytokines. We find that hypoxia/hypoglycaemia-regulated genes involved in controlling the cell cycle are either HIF-1alpha-dependent (those encoding the proteins p53, p21, Bcl-2) or HIF-1alpha-independent (p27, GADD153), suggesting that there are at least two different adaptive responses to being deprived of oxygen and nutrients. Loss of HIF-1alpha reduces hypoxia-induced expression of vascular endothelial growth factor, prevents formation of large vessels in ES-derived tumours, and impairs vascular function, resulting in hypoxic microenvironments within the tumour mass. However, growth of HIF-1alpha tumours was not retarded but was accelerated, owing to decreased hypoxia-induced apoptosis and increased stress-induced proliferation. As hypoxic stress contributes to many (patho)biological disorders, this new role for HIF-1alpha in hypoxic control of cell growth and death may be of general pathophysiological importance.
2,391 citations
TL;DR: Four error-checking algorithms are implemented in a new computer program, PedCheck, which will assist researchers in identifying all Mendelian inconsistencies in pedigree data and will provide them with useful and detailed diagnostic information to help resolve the errors.
Abstract: Summary Prior to performance of linkage analysis, elimination of all Mendelian inconsistencies in the pedigree data is essential. Often, identification of erroneous genotypes by visual inspection can be very difficult and time consuming. In fact, sometimes the errors are not recognized until the stage of running linkage-analysis software. The effort then required to find the erroneous genotypes and to cross-reference pedigree and marker data that may have been recoded and renumbered can be not only tedious but also quite daunting, in the case of very large pedigrees. We have implemented four error-checking algorithms in a new computer program, PedCheck, which will assist researchers in identifying all Mendelian inconsistencies in pedigree data and will provide them with useful and detailed diagnostic information to help resolve the errors. Our program, which uses many of the algorithms implemented in VITESSE, handles large data sets quickly and efficiently, accepts a variety of input formats, and offers various error-checking algorithms that match the subtlety of the pedigree error. These algorithms range from simple parent-offspring–compatibility checks to a single-locus likelihood-based statistic that identifies and ranks the individuals most likely to be in error. We use various real data sets to illustrate the power and effectiveness of our program.
2,158 citations
TL;DR: Genetic variation in NRAMP1 affects susceptibility to tuberculosis in West Africans, and subjects who were heterozygous for twoNRAMP1 polymorphisms in intron 4 and the 3' untranslated region of the gene were particularly overrepresented among those with tuberculosis.
Abstract: Background Genetic factors may affect the susceptibility to tuberculosis, but no specific genes governing susceptibility have been identified. In mice, natural resistance to infection with some mycobacteria is influenced by the gene for natural-resistance–associated macrophage protein 1 (Nramp1 ), but the role of the human homologue of this gene, NRAMP1, in tuberculosis is unknown. We typed polymorphisms in NRAMP1 in a case–control study of tuberculosis in the Gambia, West Africa. Methods Sequence-specific oligonucleotide hybridization and microsatellite analysis were used to type NRAMP1 polymorphisms in 410 adults (mean age, 34.7 years) with smear-positive pulmonary tuberculosis and 417 ethnically matched, healthy controls. Patients with human immunodeficiency virus infection were excluded. Results Four NRAMP1 polymorphisms were each significantly associated with tuberculosis. Subjects who were heterozygous for two NRAMP1 polymorphisms in intron 4 and the 3' untranslated region of the gene were particula...
754 citations
TL;DR: DNA priming followed by MVA boosting may provide a general immunization regime for induction of high levels of CD8+ T cells and was abrogated when the order of immunization was reversed.
Abstract: Immunization with irradiated sporozoites can protect against malaria infection and intensive efforts are aimed at reproducing this effect with subunit vaccines. A particular sequence of subunit immunization with pre-erythrocytic antigens of Plasmodium berghei, consisting of single dose priming with plasmid DNA followed by a single boost with a recombinant modified vaccinia virus Ankara (MVA) expressing the same antigen, induced unprecedented complete protection against P. berghei sporozoite challenge in two strains of mice. Protection was associated with very high levels of splenic peptide-specific interferon-γ-secreting CD8+ T cells and was abrogated when the order of immunization was reversed. DNA priming followed by MVA boosting may provide a general immunization regime for induction of high levels of CD8+ T cells.
689 citations
TL;DR: It is likely that susceptibility to most microorganisms is determined by a large number of polymorphic genes, and identification of these should provide insights into protective and pathogenic mechanisms in infectious diseases.
Abstract: ▪ Abstract Twin and adoptee studies have indicated that host genetic factors are major determinants of susceptibility to infectious diseases in humans. Twin studies have also found high heritabilities for many humoral and cellular immune responses to pathogen antigens, with most of the genetic component mapping outside of the major histocompatibility complex. Candidate gene studies have implicated several immunogenetic polymorphisms in human infectious diseases. HLA variation has been associated with susceptibility or resistance to malaria, tuberculosis, leprosy, AIDS, and hepatitis virus persistence. Variation in the tumor necrosis factor gene promoter has also been associated with several infectious diseases. Chemokine receptor polymorphism affects both susceptibility to HIV-1 infection and the rate of progression to AIDS. Inactivating mutations of the γ-interferon receptor lead to increased susceptibility to atypical mycobacteria and disseminated BCG infection in homozygous children. The active form of...
574 citations
TL;DR: The authors identified a region on chromosome 7 which co-segregates with the speech and language disorder (maximum lod score = 6.62 at θ = 0.0), confirming autosomal dominant inheritance with full penetrance.
Abstract: Between 2 and 5% of children who are otherwise unimpaired have significant difficulties in acquiring expressive and/or receptive language, despite adequate intelligence and opportunity1,2. While twin studies indicate a significant role for genetic factors in developmental disorders of speech and language1, the majority of families segregating such disorders show complex patterns of inheritance, and are thus not amenable for conventional linkage analysis2. A rare exception is the KE family, a large three-generation pedigree in which approximately half of the members are affected with a severe speech and language disorder which appears to be transmitted as an autosomal dominant monogenic trait3. This family has been widely publicised as suffering primarily from a defect in the use of grammatical suffixa-tion rules4–7, thus supposedly supporting the existence of genes specific to grammar. The phenotype, however, is broader in nature, with virtually every aspect of grammar and of language affected8–10. In addition, affected members have a severe orofa-cial dyspraxia, and their speech is largely incomprehensible to the naive listener10. We initiated a genome-wide search for linkage in the KE family and have identified a region on chromosome 7 which co-segregates with the speech and language disorder (maximum lod score = 6.62 at θ = 0.0), confirming autosomal dominant inheritance with full penetrance. Further analysis of microsatellites from within the region enabled us to fine map the locus responsible (designated SPCH1) to a 5.6-cM interval in 7q31, thus providing an important step towards its identification. Isolation of SPCH1 may offer the first insight into the molecular genetics of the developmental process that culminates in speech and language.
414 citations
TL;DR: A genome-wide scan of 93 affected sibpair families from the UK indicated a similar genetic basis for human type 1 diabetes, with the major genetic component at the MHC locus (IDDM1) explaining 34% of the familial clustering of the disease.
Abstract: Genetic analysis of a mouse model of major histocompatability complex (MHC)-associated autoimmune type 1 (insulin-dependent) diabetes mellitus (IDDM) has shown that the disease is caused by a combination of a major effect at the MHC and at least ten other susceptibility loci elsewhere in the genome. A genome-wide scan of 93 affected sibpair families (ASP) from the UK (UK93) indicated a similar genetic basis for human type 1 diabetes, with the major genetic component at the MHC locus (IDDM1) explaining 34% of the familial clustering of the disease (lambda(s)=2.5; refs 3,4). In the present report, we have analysed a further 263 multiplex families from the same population (UK263) to provide a total UK data set of 356 ASP families (UK356). Only four regions of the genome outside IDDM1/MHC, which was still the only major locus detected, were not excluded at lambda(s)=3 and lod=-2, of which two showed evidence of linkage: chromosome 10p13-p11 (maximum lod score (MLS)=4.7, P=3x10(-6), lambda(s)=1.56) and chromosome 16q22-16q24 (MLS=3.4, P=6.5x10(-5), lambda(s)=1.6). These and other novel regions, including chromosome 14q12-q21 and chromosome 19p13-19q13, could potentially harbour disease loci but confirmation and fine mapping cannot be pursued effectively using conventional linkage analysis. Instead, more powerful linkage disequilibrium-based and haplotype mapping approaches must be used; such data is already emerging for several type 1 diabetes loci detected initially by linkage.
335 citations
TL;DR: In African children with malaria, the variants present are influenced by the presence of a human leukocyte antigen (HLA) type that restricts the immune response to this epitope, which supports the view that parasite genes evolving to evade specific host defenses supports this view.
Abstract: Host-parasite coevolution has been likened to a molecular arms race, with particular parasite genes evolving to evade specific host defenses. Study of the variants of an antigenic epitope of Plasmodium falciparum that induces a cytotoxic T cell response supports this view. In African children with malaria, the variants present are influenced by the presence of a human leukocyte antigen (HLA) type that restricts the immune response to this epitope. The distribution of parasite variants may be further influenced by the ability of cohabiting parasite strains to facilitate each other's survival by down-regulating cellular immune responses, using altered peptide ligand antagonism.
268 citations
TL;DR: Results from large case control studies conducted in East and West Africa provide strong evidence that the most common African G6PD deficiency variant, G6 PD A–, is associated with a significant reduction in the risk of severe malaria for both G 6PD female heterozygotes and male hemizygotes.
Abstract: Glucose-6-phosphate dehydrogenase (G6PD) is a cytoplasmic enzyme that is essential for a cell's capacity to withstand oxidant stress. G6PD deficiency is the commonest enzymopathy of humans, affecting over 400 million persons worldwide. The geographical correlation of its distribution with the historical endemicity of malaria suggests that 66PD deficiency has risen in frequency through natural selection by malaria. This is supported by data from in vitro studies that demonstrate impaired growth of P. falciparum parasites in G6PD-deficient erythrocytes. Attempts to confirm that G6PD deficiency is protective in field studies of malaria have yielded conflicting results, but recent results from large case control studies conducted in East and West Africa provide strong evidence that the most common African G6PD deficiency variant, G6PD A-, is associated with a significant reduction in the risk of severe malaria for both G6PD female heterozygotes and male hemizygotes. The effect of female homozygotes on severe malaria remains unclear but can probably be assumed to be similar to that of comparably deficient male hemizygotes.
263 citations
TL;DR: A combined regime whereby the animals were first primed with the DNA vaccine and then boosted with MVA was the most potent protocol for the induction of both interferon-gamma-producing and cytolytic T cells against two CTL epitopes simultaneously.
244 citations
TL;DR: Low-density lipoprotein receptor related protein 5 (LRP5) was identified by DNA sequence analysis within the insulin-dependent diabetes mellitus (IDDM) locus IDDM4 on chromosome 11q13 as discussed by the authors.
TL;DR: In this article, a haplotype tree (cladogram) was constructed with three main branches (clades A-C) which account for 90% of the observed haplotypes, most likely derived from clades A and B following an ancestral recombination event.
Abstract: Linkage and segregation analysis have shown that circulating angiotensin-I converting enzyme (ACE) levels are influenced by a major quantitative trait locus that maps within or close to the ACE gene. The D variant of a 287 bp insertion/deletion (I/D) polymorphism in intron 16 of the gene is associated with high ACE levels and may also be related to increased risk of cardiovascular disease. Multiple variants that are in linkage disequilibrium with the I/D polymorphism have been described, but it is unknown if any of these are directly implicated, alone or in combination with as yet undiscovered variants, in the determination of ACE levels. An analysis of 10 polymorphisms spanning 26 kb of the ACE gene revealed a limited number of haplotypes in Caucasian British families due to strong linkage disequilibrium operating over this small chromosomal region. A haplotype tree (cladogram) was constructed with three main branches (clades A-C) which account for 90% of the observed haplotypes. Clade C is most likely derived from clades A and B following an ancestral recombination event. This evolutionary information was then used to direct a series of nested, measured haplotype analyses that excluded upstream sequences, including the ACE promoter, from harbouring the major ACE-linked variant that explains 36% of the total trait variability. Residual familial correlations were highly significant, suggesting the influence of additional unlinked genes. Our results demonstrate that a combined cladistic/measured haplotype analysis of polymorphisms within a gene provides a powerful means to localize variants that directly influence a quantitative trait.
TL;DR: The cytoplasmic domain of LRP6 is not similar to other members of the LDLR family, while comparison with LRP5 reveals proline-rich motifs that may mediate protein-protein interactions, likely to comprise a new class of the HDLR family.
TL;DR: The characterization of a widely transcribed X- linked homologue of Uty, called Utx, is reported, which maps to the proximal region of the mouse X chromosome and which detects a human X-linked homologue at Xp11.2.
Abstract: We recently have identified a ubiquitously transcribed mouse Y chromosome gene, Uty, which encodes a tetratricopeptide repeat (TPR) protein. A peptide derived from the UTY protein confers H-Y antigenicity on male cells. Here we report the characterization of a widely transcribed X-linked homologue of Uty, called Utx, which maps to the proximal region of the mouse X chromosome and which detects a human X-linked homologue at Xp11.2. Given that Uty is ubiquitously transcribed, we assayed for Utx expression from the inactive X chromosome (Xi) in mice and found that Utx escapes X chromosome inactivation. Only Smcx and the pseudoautosomal Sts gene on the mouse X chromosome have been reported previously to escape inactivation. The human UTX gene was also found to be expressed from Xi. We discuss the significance of these data for our understanding of dosage compensation of X-Y homologous genes in humans and mice.
01 Jan 1998
TL;DR: In this article, the authors reported the characterization of a widely transcribed X-linked homologue of Uty, called Utx, which maps to the proximal region of the mouse X chromosome and which detects a human X linked homologue at Xp11.2.
Abstract: We recently have identified a ubiquitously transcribed mouse Y chromosome gene, Uty , which encodes a tetratricopeptide repeat (TPR) protein. A peptide derived from the UTY protein confers H-Y antigenicity on male cells. Here we report the characterization of a widely transcribed X-linked homologue of Uty , called Utx , which maps to the proximal region of the mouse X chromosome and which detects a human X-linked homologue at Xp11.2. Given that Uty is ubiquitously transcribed, we assayed for Utx expression from the inactive X chromosome (Xi) in mice and found that Utx escapes X chromosome inactivation. Only Smcx and the pseudoautosomal Sts gene on the mouse X chromosome have been reported previously to escape inactivation. The human UTX gene was also found to be expressed from Xi. We discuss the significance of these data for our understanding of dosage compensation of X-Y homologous genes in humans and mice.
TL;DR: A novel minimal vector pTH for direct gene transfer was constructed for efficient expression of vaccine antigens and used as a vehicle for human immunodeficiency virus (HIV)- and Plasmodium falciparum-derived polyepitope genes.
TL;DR: Nonparametric linkage analyses at microsatellites surrounding D12S83 were performed in 122 North American Caucasian families containing 208 genotyped IBD-affected relative pairs and independently confirmed linkage of IBD to the chromosome 12 region that was investigated.
Abstract: Summary Genetic epidemiological studies have shown that genetic factors are important in the pathogenesis of the idiopathic inflammatory bowel diseases (IBD), Crohn disease (CD), and ulcerative colitis (UC). A genome screen in the United Kingdom found linkage of IBD to a 41-cM region of chromosome 12, surrounding D12S83. We aimed to replicate this linkage and to narrow the region of interest. Nonparametric linkage analyses at microsatellites surrounding D12S83 were performed in 122 North American Caucasian families containing 208 genotyped IBD-affected relative pairs. Transmission/disequilibrium tests (TDTs) were also performed. We confirmed that IBD is linked to chromosome 12 (peak GENEHUNTER-PLUS LOD* score 2.76 [ P = .00016] between D12S1724 and D12S90). The evidence for linkage is contributed by both the group of CD-affected relative pairs (peak GENEHUNTER-PLUS LOD* score 1.79 [ P = .0021] between D12S1724 and D12S90) and the group of UC-affected relative pairs (peak GENEHUNTER-PLUS LOD* score 1.82 [ P = .0019] at D12S335). The TDT is positive at the D12S83 locus (global χ 2 = 16.41, 6 df, P = .012). In conclusion, we have independently confirmed linkage of IBD to the chromosome 12 region that we investigated. A positive TDT at D12S83 suggests that we have greatly narrowed the chromosome 12 region that contains an IBD locus.
TL;DR: Genetic susceptibility to tuberculosis among Gambians may be partly determined by genes in the IL1 gene cluster on chromosome 2, according to a study of tuberculosis cases and healthy blood donor controls.
TL;DR: MBP deficiency is not a significant risk factor for persistent HBV, severe malaria nor pulmonary TB in West Africa, and the most common mutation in Africans was weakly associated with resistance to TB.
Abstract: We retrospectively studied MBP genotypes in patients with malaria, tuberculosis (TB), and persistent hepatitis B virus (HBV) carriage, in clinics and hospitals in The Gambia. Children under 10 years with cerebral malaria and/or severe malarial anaemia, were compared with children with symptomatic, mild malaria, and controls of the same age and ethnicity. Adult TB cases with smear-positive pulmonary TB were compared with healthy blood donors from the same ethnic groups. Malaria cases and controls were tested for hepatitis B core antibody (anti-HBc) and surface antigen (HBsAg). TB patients were tested for HIV antibodies. Genotyping used sequence-specific oligonucleotide analysis to identify MBP variant alleles. Overall, 46% (944/2041) of patients and controls were homozygous for the wild-type MBP allele, 45% (922/2041) were carriers of a single variant allele and 8.6% (175/2041) had two variant alleles. Neither homozygotes nor heterozygotes for MBP variants were at increased risk of clinical malaria, persistent HBV carriage or TB. The most common mutation in Africans, the codon 57 variant allele, was weakly associated with resistance to TB (221/794 in TB cases and 276/844 in controls, p = 0.037). MBP deficiency is not a significant risk factor for persistent HBV, severe malaria nor pulmonary TB in West Africa.
TL;DR: In medium/high incidence Caucasian populations from the United States of America, United Kingdom and Sardinia, the bias in male incidence is largely restricted to the DR3/X category of patients with a M:F ratio of 1.7, evidence for aetiological heterogeneity at the IDDM1/MHC locus and, therefore, in the search for non-M HC loci in type 1 diabetes, conditioning of linkage data by HLA type is advised.
Abstract: It is generally assumed that the male:female (M:F) ratio in patients with type 1 (insulin-dependent) diabetes mellitus (IDDM) is 1. A recent survey, however, revealed that high incidence countries (mainly European) have a high M:F ratio and low incidence ones (Asian and African) have a low M:F ratio1. We have now analysed the M:F ratio according to genotype at the major locus, the major histocompatibility complex (MHC; IDDM1). There are two main IDDM1 susceptibility haplotypes, HLA-DR3 and -DR4, which are present in 95% of Caucasian cases2,3,4. We report here that in medium/high incidence Caucasian populations from the United States of America, United Kingdom and Sardinia (1307 cases), the bias in male incidence is largely restricted to the DR3/X category of patients (X ≠ DR4) with a M:F ratio of 1.7 (P = 9.3 × 10–7), compared with a ratio of 1.0 in the DR4/Y category (Y ≠ DR3). This is additional evidence for significant heterogeneity between the aetiology of 'DR4-associated' and 'DR3-associated' diabetes5,6,7,8,9,10,11,12,13. We analysed linkage of type 1 diabetes to chromosome X, and as expected, most of the linkage to Xp13–p11 was in the DR3/X affected sibpair families (n = 97; peak multipoint MLS at DXS1068 = 3.5, P = 2.7 × 10–4; single point MLS = 4.5, P = 2.7 × 10–5). This is evidence for aetiological heterogeneity at the IDDM1/MHC locus and, therefore, in the search for non-MHC loci in type 1 diabetes, conditioning of linkage data by HLA type is advised.
01 Jan 1998
TL;DR: The results of this study suggest that HLA-DR genes may have a weak effect on susceptibility to AS independent of H LA-B27, but do not support suggestions that they affect disease severity or different clinical manifestations.
Abstract: Objective.
To analyze the effect of HLA-DR genes on susceptibility to and severity of ankylosing spondylitis (AS).
Methods.
Three hundred sixty- three white British AS patients were studied; 149 were carefully assessed for a range of clinical manifestations, and disease severity was assessed using a structured questionnaire. Limited HLA class I typing and complete HLA-DR typing were performed using DNA-based methods. HLA data from 13,634 healthy white British bone marrow donors were used for comparison.
Results.
A significant association between DR1 and AS was found, independent of HLA-B27 (overall odds ratio [OR] 1.4, 95% confidence interval [95% CI] 1.1-1.8, P = 0.02; relative risk [RR] 2.7, 95% CI 1.5-4.8, P = 6 x 10-4 among homozygotes; RR 2.1, 95% CI 1.5-2.8, P = 5 x 10-6 among heterozygotes). A large but weakly significant association between DR8 and AS was noted, particularly among DR8 homozygotes (RR 6.8, 95% CI 1.6-29.2, P = 0.01 among homozygotes; RR 1.6, 95% CI 1.0-2.7, P = 0.07 among heterozygotes). A negative association with DR12 (OR 0.22, 95% CI 0.09-0.5, P = 0.001) was noted. HLA-DR7 was associated with younger age at onset of disease (mean age at onset 18 years for DR7-positive patients and 23 years for DR7-negative patients; Z score 3.21, P = 0.001). No other HLA class I or class H associations with disease severity or with different clinical manifestations of AS were found.
Conclusion.
The results of this study suggest that HLA-DR genes may have a weak effect on susceptibility to AS independent of HLA-B27, but do not support suggestions that they affect disease severity or different clinical manifestations.
TL;DR: The resolution of the originally defined Idd3 locus into at least four separate loci, I dd3, IDD10, Idd17, and Idd18, illustrates the complex poly genic nature of diabetes.
Abstract: Multiple genes control the development of autoimmune diabetes both in humans and in the nonobese diabetic (NOD) strain of mouse. Previously, three insulin-dependent diabetes (Idd) genes, Idd3, Idd10, and Idd17, were localized to mouse Chromosome (Chr) 3. The B10- or B6-derived resistance alleles at Idd10 and Idd3 together provide the NOD mouse with nearly complete protection from diabetes. In the present study, the 10.2-cM region encoding Idd10 was defined further with newly developed congenic strains. A locus, located in the centromeric 2.1 cM of the 10.2 cM region, contributed to the Idd10 trait. However, this locus did not account for the full effect of Idd10, suggesting the presence of a second gene in the distal portion of the 10.2-cM region. This second gene is designated as Idd18 and is localized to a 5.1-cM region. The resolution of the originally defined Idd3 locus into at least four separate loci, Idd3, Idd10, Idd17, and Idd18, illustrates the complex polygenic nature of diabetes.
TL;DR: One form of maturity‐onset diabetes of the young, Type 3 (MODY3), results from mutations in the gene coding for hepatocyte nuclear factor‐1α (HNF‐1 α), a transcription factor first described in the liver.
Abstract: One form of maturity-onset diabetes of the young, Type 3 (MODY3), results from mutations in the gene coding for hepatocyte nuclear factor-1alpha (HNF-1alpha), a transcription factor first described in the liver. MODY3 is characterized by a defective glucose-stimulated insulin secretion. Earlier observations of glycosuria with normal blood glucose levels in some MODY families suggest an additional renal manifestation of the respective genetic defect. We measured the renal threshold for glucose in five diabetic carriers of a missense mutation (Arg 272 His) in HNF-1alpha and, for comparison, in eight Type 1 diabetic patients, applying a non-invasive protocol of frequent parallel blood and urine sampling during a slow shift in blood glucose levels. We found that the mean renal threshold for glucose was lowered in the HNF-1alpha diabetic patients compared to those with Type 1 diabetes (6.5 +/- 0.9 mmol l(-1) vs 10.7 +/- 0.5 mmol l(-1); p < 0.01). This lowered glucose threshold might be an indication of an extra-pancreatic effect of HNF-1alpha gene mutations in humans. Defects in HNF-1alpha may lead to an altered tubular glucose reabsorption, possibly due to decreased expression of the renal glucose transporter proteins involved in reabsorption of glucose from the urine.
TL;DR: A large case-control study of children with the severe forms of this disease-cerebral malaria and severe malarial anaemia suggests that there may be heterogeneity in genetic susceptibility to this condition between these 2 African populations.
Abstract: Many genes have been shown to be involved in host susceptibility to the severe forms of Plasmodium falciparum malaria but it is likely that a large number of malaria-susceptibility genes remain to be determined. We conducted a large case-control study of children with the severe forms of this disease—cerebral malaria and severe malarial anaemia—to attempt to identify these genes. Over 1200 children in The Gambia were typed for polymorphisms of the intercellular adhesion molecule 1 ( ICAM-1 ), complement receptor 1 ( CR-1 ) and interleukin 1 receptor antagonist ( IL-IRA ) genes. None of the polymorphisms typed was significantly associated with severe disease. These data differed significantly from the results of a previous study (χ 2 = 8·81; P = 0·003) in which the ICAM-1 gene polymorphism was shown to be significantly associated with cerebral malaria in a case-control study of 547 subjects in Kenya. This suggests that there may be heterogeneity in genetic susceptibility to this condition between these 2 African populations.
TL;DR: DNA samples isolated from this family of Chinese origin have been tested with genetic markers at chromosome 16p12-q12, and the association of infantile convulsions with paroxysmal dyskinetic movements could be genetically homogeneous, suggesting the ICCA syndrome in this family atypical.
Abstract: We have studied one family of Chinese origin, in which benign infantile convulsions and paroxysmal choreoathetosis (of the dystonic form) were co-inherited as a single autosomal dominant trait. This association is specific to ICCA syndrome, which we have recently described in four French families. Some patients in the new family also exhibit recurrence of epileptic seizures at a much later age, making the ICCA syndrome in this family atypical. DNA samples isolated from this family of 22 members (9 affected) have been tested with genetic markers at chromosome 16p12-q12, in which region the ICCA syndrome has previously been linked. Confirmation of linkage to this pericentromeric region of human chromosome 16 has been obtained and no critical meiotic recombination event has been detected in the ICCA region. This result suggests that, in contrast to marked clinical heterogeneity, the association of infantile convulsions with paroxysmal dyskinetic movements could be genetically homogeneous.
TL;DR: Cosegregation of MNGIE with a single chromosomal region in families with diverse ethnic backgrounds suggests that an important locus for this disorder is mapped, and no evidence to implicate three candidate genes is found.
Abstract: Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) syndrome is a rare, multisystem disorder characterized clinically by ptosis, progressive external ophthalmoplegia, gastrointestinal dysmotility, leukoencephalopathy, thin body habitus, and myopathy. Laboratory studies reveal defects of oxidative-phosphorylation and multiple mtDNA deletions frequently in skeletal muscle. We studied four ethnically distinct families affected with this apparently autosomal recessive disorder. Probands from each family were shown, by Southern blot, to have multiple mtDNA deletions in skeletal muscle. We mapped the MNGIE locus to 22q13.32-qter, distal to D22S1161, with a maximum two-point LOD score of 6.80 at locus D22S526. Cosegregation of MNGIE with a single chromosomal region in families with diverse ethnic backgrounds suggests that we have mapped an important locus for this disorder. We found no evidence to implicate three candidate genes in this region, by using direct sequence analysis for DNA helicase II and by assaying enzyme activities for arylsulfatase A and carnitine palmitoyltransferase.
TL;DR: This work demonstrates that a large number of genes are probably important in susceptibility to mycobacterial pathogens and provides a model for the investigation of genetic susceptibility to other infectious diseases.
TL;DR: The novel recombinant Ty/MVA prime/boost combination with these constructs provides a safe alternative for evaluation for human vaccination against P. falciparum malaria.
Abstract: The desirability of inducing cytotoxic T cell responses to defined epitopes in humans has led to the development of a variety of recombinant delivery systems. Recombinant protein particles derived from a yeast retrotransposon (Ty) and the modified Ankara vaccinia (MVA) virus can deliver large epitope strings or even whole proteins. Both have previously been administered safely in humans. Immunization with recombinant Ty and MVA containing a single Plasmodium berghei class I-binding epitope provided 95% sterile protection against malaria in mice. The sequence of immunization, Ty followed by MVA, was critical to elicit high levels of IFN-gamma-producing cells and protection. The reciprocal sequence (MVA/TY) or homologous boosting was not protective. Both constructs (Ty and MVA) contain the H-2Kd-restricted pb9 CTL epitope from the circumsporozoite protein of P. berghei among a string of 8-15 human P. falciparum-derived CTL epitopes restricted through 7 common HLA alleles as well as widely recognized CD4 T cell epitopes. Thus, the novel recombinant Ty/MVA prime/boost combination with these constructs provides a safe alternative for evaluation for human vaccination against P. falciparum malaria.
TL;DR: A rat PAC library was constructed in the vector pPAC4 from genomic DNA isolated from female Brown Norway rats, providing a new resource for rat genome analysis, in particular the identification of genes involved in models of multifactorial disease.
TL;DR: The full-length recombinant Menkes protein was shown by immunofluorescence to localize to the Golgi apparatus and the alternatively spliced form, lacking sequences for transmembrane domains 3 and 4 encoded by exon 10, was shown to localizing to the endoplasmic reticulum.
Abstract: Menkes disease arises from a genetic impairment in copper transport. The gene responsible for the phenotype has been identified as a copper transporting ATPase ( ATP7A ). Recently, the protein encoded by the ATP7A gene has been localized to the Golgi complex. In order to investigate the role of the Menkes disease protein in copper transport, recombinant constructs containing both the full-length open reading frame and an alternatively spliced form have been successfully expressed and localized in mammalian cells. Other studies of a patient with occipital horn syndrome, an allelic variant of Menkes disease, have demonstrated that only this alternatively spliced isoform and not the full-length form is expressed in this patient. The milder form of this patient's phenotype suggests that the alternatively spliced isoform has some functional role in copper transport. In the present study the full-length recombinant Menkes protein was shown by immunofluorescence to localize to the Golgi apparatus and the alternatively spliced form, lacking sequences for transmembrane domains 3 and 4 encoded by exon 10, was shown to localize to the endoplasmic reticulum. Using sequences from exon 10 fused to a non-Golgi reporter molecule, a 38 amino acid sequence containing transmembrane domain 3 of the Menkes protein was found to be sufficient for localization to the Golgi complex. Therefore, the protein sequence encoded by exon 10 may be responsible for this differential localization and both isoforms may be required for comprehensive transport of copper within the cell.