Summary
Background
Pemphigus foliaceus (PF) is an epidermal autoimmune disease, characterized by the presence of autoantibodies against the desmosomal protein desmoglein 1. Genetic and environmental ...factors contribute to PF, a complex disease that is endemic in Brazil and Colombia and neighbouring countries, and in Tunisia. Long noncoding RNAs (lncRNAs) may participate in gene regulation by interacting with DNA, proteins and other RNAs. Dysregulation of lncRNAs has recently been recognized as an important coplayer in the onset or progression of complex diseases. In addition, single‐nucleotide polymorphisms (SNPs) located in lncRNA genes have been associated with differential risk to cancer, autoimmunity and infection.
Objectives
Here, we aimed to investigate whether SNPs in lncRNA genes are associated with differential susceptibility to endemic PF.
Materials and methods
We integrated data from the lncRNA SNP database with genome‐wide genotype data obtained for 229 patients and 6681 controls. We tested the association between endemic PF and 2080 SNPs located in lncRNAs applying logistic regression.
Results
The most significantly associated SNP was rs7144332 (OR = 1·63, P = 2·8 × 10–6), located in the lncRNA gene AL110292·1. Results for five other SNPs were suggestive of association (P < 0·001). In silico analysis indicated that five of the six SNPs impact transcription, three may influence lncRNA's secondary structure, and three may alter microRNA–lncRNA interactions.
Conclusions
We showed, for the first time, that variation in lncRNA genes may influence pemphigus pathogenesis. Our findings highlight the importance of lncRNA variation in autoimmune and possibly other complex diseases and suggest polymorphisms for functional validation.
What's already known about this topic?
The multifactorial autoimmune blistering skin disease pemphigus foliaceus (PF) presents a genetic susceptibility component that is not fully understood.
Although PF is rare worldwide, it reaches a prevalence of 1·5–3% in some regions of Brazil, the highest ever reported for an autoimmune disease.
Long noncoding RNA (lncRNA) polymorphisms have been associated with some complex diseases but have not yet been studied in any form of pemphigus.
What does this study add?
Genetic variation of lncRNA may influence susceptibility to PF via its effect on lncRNA structure, on transcription of nearby genes, and on microRNA–lncRNA interactions.
We have shown, for the first time, that variation in lncRNA genes may influence PF pathogenesis.
What is the translational message?
Our findings show that lncRNA variation is part of the polygenic risk component in the pathogenesis of pemphigus and possibly other complex skin diseases, indicating that lncRNAs can be explored as potential new drug targets.
Linked Comment: Amber. Br J Dermatol 2019; 181:241–242.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Following the candidate gene approach we analyzed the CD40L, CD40, BLYS and CD19 genes that participate of B-cell co-stimulation, for association with pemphigus foliaceus (PF), an organ-specific ...autoimmune disease, characterized by the detachment of epidermal cells from each other (acantholysis) and presence of autoantibodies specific for desmoglein 1 (dsg1), an epidermal cell-adhesion molecule. The disease is endemic in certain regions of Brazil and also is known as fogo selvagem. Complex interactions among environmental and genetic susceptibility factors contribute to the manifestation of this multifactorial disease. The sample included 179 patients and 317 controls. Strong significant association was found with CD40L-726T>C (odds ratio, OR=5.54 and 0.30 for T+ and C+ genotypes, respectively). In addition, there were significant negative associations with CD40 -1T (OR=0.61) and BLYS-871T (OR=0.62) due to the decrease of the frequency of both homo- and heterozygotes in the patient group. No associations were found with variants of CD19 gene. Gene-gene interactions were observed between CD40 and BLYS, and between CD40L and BLYS. So, the dominant protective effects of CD40L-726C and of CD40 -1T only manifest in BLYS-871T+ individuals, and vice versa. We conclude that genetic variability of CD40L, CD40 and BLYS is an important factor for PF pathogenesis.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
lncRNA polymorphisms in EPF Lobo‐Alves, S.C.; Augusto, D.G.; Magalhães, W.C.S. ...
British journal of dermatology (1951),
August 2019, 2019-08-00, 20190801, Volume:
181, Issue:
2
Journal Article
Peer reviewed
Open access
Summary
Pemphigus foliaceus (PF) is a disease that causes painful blisters in the skin. Due to genetic and environmental reasons, the person's own immune system produces antibodies that attack ...proteins present in the top layer of the skin (the epidermis). Although PF is rare worldwide, there are some geographic regions where many people develop this disease, known as the endemic form of PF (EPF). In Brazil, EPF is also known as fogo selvagem. This study aimed at finding out if single changes in the DNA (called SNPs – single nucleotide polymorphisms) located in genes called lncRNA genes predispose people to EPF. There are several different variants of SNPs. The frequencies of 2,080 SNPs were compared between 229 EPF patients and 6,681 people without pemphigus (the controls). A variant of the SNP called rs7144332 was significantly more frequent among EPF patients than people without EPF, and is therefore associated with increased risk. Results for another five SNPs suggested that they also influence the susceptibility to (risk of) EPF. Further study showed that five of these six SNPs could affect the amount of lncRNAs or proteins produced by nearby genes. Along with other findings, this study shows that genetic variants of lncRNAs might contribute to the development of pemphigus, highlighting their importance in autoimmune and possibly other complex diseases.
Linked Article: Lobo‐Alves et al. Br J Dermatol 2019; 181:324–331
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
It is well accepted that the Americas were the last continents reached by modern humans, most likely through Beringia. However, the precise time and mode of the colonization of the New World remain ...hotly disputed issues. Native American populations exhibit almost exclusively five mitochondrial DNA (mtDNA) haplogroups (A–D and X). Haplogroups A–D are also frequent in Asia, suggesting a northeastern Asian origin of these lineages. However, the differential pattern of distribution and frequency of haplogroup X led some to suggest that it may represent an independent migration to the Americas. Here we show, by using 86 complete mitochondrial genomes, that all Native American haplogroups, including haplogroup X, were part of a single founding population, thereby refuting multiple-migration models. A detailed demographic history of the mtDNA sequences estimated with a Bayesian coalescent method indicates a complex model for the peopling of the Americas, in which the initial differentiation from Asian populations ended with a moderate bottleneck in Beringia during the last glacial maximum (LGM), around ∼23,000 to ∼19,000 years ago. Toward the end of the LGM, a strong population expansion started ∼18,000 and finished ∼15,000 years ago. These results support a pre-Clovis occupation of the New World, suggesting a rapid settlement of the continent along a Pacific coastal route.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The human leukocyte antigen (HLA) are the most polymorphic genes in the human genome. Because of their importance for antigen recognition, HLA molecules play a central role in host defense and graft ...rejection upon transplantation. The aim of this study was to characterize allelic diversity of the classical HLA genes HLA‐A, ‐B, ‐C, ‐DRA, ‐DRB1, ‐DQA1, ‐DQB1, ‐DPA1, ‐DPB1, and the non‐classical class I genes HLA‐E, ‐F and ‐G at high‐resolution for a population of predominantly European ancestry from Curitiba, Brazil. Genotyping of 108 individuals was performed by next‐generation sequencing on the MiSeq platform and also by Sanger sequencing. The genotype distributions of all loci were in accordance with Hardy‐Weinberg equilibrium (P > 0.05) and a total of 202 HLA variants at second field resolution were observed for the 12 loci. The strongest linkage disequilibrium (r2 = 1.0, P < 10−5) was observed for the following pairs of alleles: HLA‐B*42:01:01 ~ HLA‐DRB1*03:02:01; HLA‐B*14:02:01 ~ HLA‐C*08:02:01; B*42:01:01 ~ HLA‐C*17:01:01; HLA‐DRB1*03:01:01 ~ HLA‐DQB1*02:01:01 ~ DRB1*03:01:01 ~ HLA‐DQB1*02:01:01; DRB1*13:01:01~ HLA‐DQB1*06:03:01 and HLA‐DRB1*09:01:02 ~ HLA‐DQA1*03:02. This is the first study to characterize all 12 HLA genes at high resolution in a single population. On the basis of the allelic frequencies of worldwide populations and principal component analysis, we confirmed the similarity of the study population to European and other Euro‐descendant populations.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
The large and diverse population of Latin America is potentially a powerful resource for elucidating the genetic basis of complex traits through admixture mapping. However, no genome-wide ...characterization of admixture across Latin America has yet been attempted. Here, we report an analysis of admixture in thirteen Mestizo populations (i.e. in regions of mainly European and Native settlement) from seven countries in Latin America based on data for 678 autosomal and 29 X-chromosome microsatellites. We found extensive variation in Native American and European ancestry (and generally low levels of African ancestry) among populations and individuals, and evidence that admixture across Latin America has often involved predominantly European men and both Native and African women. An admixture analysis allowing for Native American population subdivision revealed a differentiation of the Native American ancestry amongst Mestizos. This observation is consistent with the genetic structure of pre-Columbian populations and with admixture having involved Natives from the area where the Mestizo examined are located. Our findings agree with available information on the demographic history of Latin America and have a number of implications for the design of association studies in population from the region.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
To scrutinize the male ancestry of extant Native American populations, we examined eight biallelic and six microsatellite polymorphisms from the nonrecombining portion of the Y chromosome, in 438 ...individuals from 24 Native American populations (1 Na Dené and 23 South Amerinds) and in 404 Mongolians. One of the biallelic markers typed is a recently identified mutation (M242) characterizing a novel founder Native American haplogroup. The distribution, relatedness, and diversity of Y lineages in Native Americans indicate a differentiated male ancestry for populations from North and South America, strongly supporting a diverse demographic history for populations from these areas. These data are consistent with the occurrence of two major male migrations from southern/central Siberia to the Americas (with the second migration being restricted to North America) and a shared ancestry in central Asia for some of the initial migrants to Europe and the Americas. The microsatellite diversity and distribution of a Y lineage specific to South America (Q-M19) indicates that certain Amerind populations have been isolated since the initial colonization of the region, suggesting an early onset for tribalization of Native Americans. Age estimates based on Y-chromosome microsatellite diversity place the initial settlement of the American continent at ∼14,000 years ago, in relative agreement with the age of well-established archaeological evidence.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The mannose binding lectin (
MBL2) polymorphism is responsible for a common immunodeficiency in the human species. There were suggestions that the
MBL2 polymorphism has been under balancing ...selection, based on the high global frequency of alleles generating MBL deficiency and on the worldwide distribution of diseases negatively associated with them. To describe the distribution of
MBL2 allelic haplotypes in Brazilian populations and to discuss the evolution of this polymorphism, we analyzed six South Brazilian populations (152 Guarani Amerindian, 239 Kaingang Amerindian, 107 admixed, Brazilian 32 Afro-Brazilian, 202 Euro-Brazilian and 16 Oriental-Brazilian). Eight haplotypes were observed:
MBL2*HYPA, LYQA, LYPA, LXPA, LYPB, LYQC, HYPD, and
LYPD. In addition, through sequencing of the promoter and exon 1 from Amerindian and Oriental individuals, three new single-nucleotide polymorphisms (SNPs) were found in the
MBL2 promoter region in the Kaingang. Analysis of the sequencing data by neutrality tests (Tajima’s D and Fu and Li’s D* and F*) revealed no deviation from selective neutrality equilibrium in the Guarani and Kaingang. Significant Fay and Wu’s H results are explained by the recent gene flow in these populations. Contrarily to previous thoughts, stochastic evolutionary factors seem therefore to have had a predominant role in shaping the
MBL2 polymorphism, at least in the Amerindians.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Killer cell immunoglobulin‐like receptor (KIR) genes encode cell surface molecules that recognize HLA molecules and modulate the activity of natural killer (NK) cells. KIR genes exhibit presence and ...absence polymorphism, which generates a variety of gene‐content haplotypes in worldwide populations. KIR gene‐content variation is implicated in many diseases and is also important for placentation and transplantation. Because of the complexity of KIR polymorphism, variation in this family is still mostly studied at the gene‐content level, even with the advent of next‐generation sequencing (NGS) methods. Gene‐content determination is generally expensive and/or time‐consuming. To overcome these difficulties, we developed a method based on multiplex polymerase chain reaction with specific sequence primers (PCR‐SSP) followed by melting curve analysis that allows cost‐effective, precise and fast generation of results. Our method was 100% concordant with a gel‐based method and 99.9% concordant with presence and absence determination by NGS. The limit of detection for accurate typing was 30 ng of DNA (0.42 μM) with 260/230 and 260/280 ratios as low as 0.19 and of 0.44. In addition, we developed a user‐friendly Java‐based computational application called killerPeak that interprets the raw data generated by Viia7 or QuantStudio 7 quantitative PCR machines and reliably exports the final genotyping results in spreadsheet file format. The combination of a reliable method that requires low amount of DNA with an automated interpretation of results allows scaling the KIR genotyping in large cohorts with reduced turnaround time.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
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