BACKGROUND: Neurodegeneration with brain iron accumulation (NBIA) are a group of clinically and genetically heterogeneous diseases characterized by iron overload in basal ganglia and progressive neurodegeneration. Little is known about the epidemiology of NBIA disorders. In the absence of large-scale population-based studies, obtaining reliable epidemiological data requires innovative approaches. METHODS: All pathogenic variants were collected from the 13 genes associated with autosomal recessive NBIA (PLA2G6, PANK2, COASY, ATP13A2, CP, AP4M1, FA2H, CRAT, SCP2, C19orf12, DCAF17, GTPBP2, REPS1). The allele frequencies of these disease-causing variants were assessed in exome/genome collections: the Genome Aggregation Database (gnomAD) and our in-house database. Lifetime risks were calculated from the sum of allele frequencies in the respective genes under assumption of Hardy-Weinberg equilibrium. FINDINGS: The combined estimated lifetime risk of all 13 investigated NBIA disorders is 0.88 (95% confidence interval 0.70-1.10) per 100,000 based on the global gnomAD dataset (n = 282,912 alleles), 0.92 (0.65-1.29) per 100,000 in the European gnomAD dataset (n = 129,206), and 0.90 (0.48-1.62) per 100,000 in our in-house database (n = 44,324). Individually, the highest lifetime risks (>0.15 per 100,000) are found for disorders caused by variants in PLA2G6, PANK2 and COASY. INTERPRETATION: This population-genetic estimation on lifetime risks of recessive NBIA disorders reveals frequencies far exceeding previous population-based numbers. Importantly, our approach represents lifetime risks from conception, thus including prenatal deaths. Understanding the true lifetime risk of NBIA disorders is important in estimating disease burden, allocating resources and targeting specific interventions. FUNDING: This work was carried out in the framework of TIRCON ("Treat Iron-Related Childhood-Onset Neurodegeneration").
- MeSH
- Databases, Genetic MeSH
- Child MeSH
- Nuclear Proteins MeSH
- Ubiquitin-Protein Ligase Complexes MeSH
- Humans MeSH
- Mitochondrial Proteins genetics MeSH
- Brain pathology MeSH
- Neuroaxonal Dystrophies * epidemiology genetics pathology MeSH
- Neurodegenerative Diseases * epidemiology genetics pathology MeSH
- Iron Metabolism Disorders * genetics pathology MeSH
- Calcium-Binding Proteins MeSH
- Check Tag
- Child MeSH
- Humans MeSH
- Publication type
- Journal Article MeSH
A collaborative effort was carried out by the Spanish and Portuguese Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG) to promote knowledge exchange between associate laboratories interested in the implementation of indel-based methodologies and build allele frequency databases of 38 indels for forensic applications. These databases include populations from different countries that are relevant for identification and kinship investigations undertaken by the participating laboratories. Before compiling population data, participants were asked to type the 38 indels in blind samples from annual GHEP-ISFG proficiency tests, using an amplification protocol previously described. Only laboratories that reported correct results contributed with population data to this study. A total of 5839 samples were genotyped from 45 different populations from Africa, America, East Asia, Europe and Middle East. Population differentiation analysis showed significant differences between most populations studied from Africa and America, as well as between two Asian populations from China and East Timor. Low FST values were detected among most European populations. Overall diversities and parameters of forensic efficiency were high in populations from all continents.
- MeSH
- Databases, Nucleic Acid MeSH
- DNA Fingerprinting MeSH
- Ethnicity genetics MeSH
- Gene Frequency MeSH
- Genotype MeSH
- Polymorphism, Single Nucleotide * MeSH
- Laboratories statistics & numerical data MeSH
- Humans MeSH
- Microsatellite Repeats MeSH
- INDEL Mutation * MeSH
- Genetics, Population * MeSH
- Racial Groups genetics MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
BACKGROUND: Tetranucleotide Short Tandem Repeats (STRs) for human identification and common use in forensic cases have recently been used to address the population genetics of the North-Eastern Mediterranean area. However, to gain confidence in the inferences made using STRs, this kind of analysis should be challenged with changes in three main aspects of the data, i.e. the sizes of the samples, their distance across space and the genetic background from which they are drawn. AIM: To test the resilience of the gradients previously detected in the North-Eastern Mediterranean to the enlargement of the surveyed area and population set, using revised data. SUBJECTS AND METHODS: STR genotype profiles were obtained from a publicly available database (PopAffilietor databank) and a dataset was assembled including >7000 subjects from the Arabian Peninsula to Scandinavia, genotyped at eight loci. Spatial principal component analysis (sPCA) was applied and the frequency maps of the nine alleles which contributed most strongly to sPC1 were examined in detail. RESULTS: By far the greatest part of diversity was summarised by a single spatial principal component (sPC1), oriented along a SouthEast-to-NorthWest axis. The alleles with the top 5% squared loadings were TH01(9.3), D19S433(14), TH01(6), D19S433(15.2), FGA(20), FGA(24), D3S1358(14), FGA(21) and D2S1338(19). These results confirm a clinal pattern over the whole range for at least four loci (TH01, D19S433, FGA, D3S1358). CONCLUSIONS: Four of the eight STR loci (or even alleles) considered here can reproducibly capture continental arrangements of diversity. This would, in principle, allow for the exploitation of forensic data to clarify important aspects in the formation of local gene pools.
- MeSH
- Gene Frequency * MeSH
- Genetic Variation * MeSH
- Genotype * MeSH
- Microsatellite Repeats * MeSH
- Genetics, Population MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Africa, Northern MeSH
- Middle East MeSH
- Mediterranean Region MeSH
A comprehensive knowledge of human leukocyte antigen (HLA) molecular variation worldwide is essential in human population genetics research and disease association studies and is also indispensable for clinical applications such as allogeneic hematopoietic cell transplantation, where ensuring HLA compatibility between donors and recipients is paramount. Enormous progress has been made in this field thanks to several decades of HLA population studies allowing the development of helpful databases and bioinformatics tools. However, it is still difficult to appraise the global HLA population diversity in a synthetic way. We thus introduce here a novel approach, based on approximately 2000 data sets, to assess this complexity by providing a fundamental synopsis of the most frequent HLA alleles observed in different regions of the world. This new knowledge will be useful not only as a fundamental reference for basic research, but also as an efficient guide for clinicians working in the field of transplantation.
- MeSH
- Alleles * MeSH
- Gene Frequency MeSH
- HLA Antigens * genetics immunology MeSH
- Humans MeSH
- Hematopoietic Stem Cell Transplantation * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
Aims: Genomic studies play a major role in variant observations between and within populations and in identifying causal relationships between genotypes and phenotypes. Analyses using databases such as gnomAD can provide insight into the frequencies of alleles in large populations. There have been reports that detail such frequencies for several countries and ethnic groups, but as yet, there are no such datasets for the Czech population. Patients and Methods: Whole-exome sequencing (WES) data from 222 individuals from the Czech Republic were analyzed by The Genome Analysis Toolkit best practices pipeline. These data were annotated with the ANNOVAR tool, and the allele frequencies were computed. Results: We developed a database that contains 300,111 variants in 17,512 genes. It is accessible through a simple web query available at prot2hg.com/variantbrowser. Gene-based analyses identified those genes that are most tolerant to variants in our population. Second, allele frequencies in our population were compared to the gnomAD database and groups of variants frequent in our population, but ultra-rare in gnomAD as a whole were identified. Conclusion: This tool should be useful for detecting local variants in the Czech population of patients with neurogenetic diseases.
- MeSH
- Alleles MeSH
- Databases, Genetic * MeSH
- Adult MeSH
- Phenotype MeSH
- Gene Frequency genetics MeSH
- Genetic Variation genetics MeSH
- Genomics methods MeSH
- Genotype MeSH
- Humans MeSH
- Nervous System Diseases genetics MeSH
- Neurodegenerative Diseases genetics MeSH
- Sequence Analysis, DNA methods MeSH
- Exome Sequencing methods MeSH
- High-Throughput Nucleotide Sequencing methods MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Dataset MeSH
- Geographicals
- Czech Republic MeSH
Importance: The mechanisms behind the phenotypic variability and reduced penetrance in autosomal recessive Stargardt disease (STGD1), often a blinding disease, are poorly understood. Identification of the unknown disease modifiers can improve patient and family counseling and provide valuable information for disease management. Objective: To assess the association of incompletely penetrant ABCA4 alleles with sex in STGD1. Design, Setting, and Participants: Genetic data for this cross-sectional study were obtained from 2 multicenter genetic studies of 1162 patients with clinically suspected STGD1. Unrelated patients with genetically confirmed STGD1 were selected. The data were collected from June 2016 to June 2019, and post hoc analysis was performed between July 2019 and January 2020. Main Outcomes and Measures: Penetrance of reported mild ABCA4 variants was calculated by comparing the allele frequencies in the general population (obtained from the Genome Aggregation Database) with the genotyping data in the patient population (obtained from the ABCA4 Leiden Open Variation Database). The sex ratio among patients with and patients without an ABCA4 allele with incomplete penetrance was assessed. Results: A total of 550 patients were included in the study, among which the mean (SD) age was 45.7 (18.0) years and most patients were women (311 [57%]). Five of the 5 mild ABCA4 alleles, including c.5603A>T and c.5882G>A, were calculated to have incomplete penetrance. The women to men ratio in the subgroup carrying c.5603A>T was 1.7 to 1; the proportion of women in this group was higher compared with the subgroup not carrying a mild allele (difference, 13%; 95% CI, 3%-23%; P = .02). The women to men ratio in the c.5882G>A subgroup was 2.1 to 1, and the women were overrepresented compared with the group carrying no mild allele (difference, 18%; 95% CI, 6%-30%; P = .005). Conclusions and Relevance: This study found an imbalance in observed sex ratio among patients harboring a mild ABCA4 allele, which concerns approximately 25% of all patients with STGD1, suggesting that STGD1 should be considered a polygenic or multifactorial disease rather than a disease caused by ABCA4 gene mutations alone. The findings suggest that sex should be considered as a potential disease-modifying variable in both basic research and clinical trials on STGD1.
- MeSH
- ATP-Binding Cassette Transporters genetics metabolism MeSH
- Alleles MeSH
- DNA genetics MeSH
- Gene Frequency MeSH
- Genotype MeSH
- Middle Aged MeSH
- Humans MeSH
- Mutation * MeSH
- DNA Mutational Analysis MeSH
- Cross-Sectional Studies MeSH
- Sex Distribution MeSH
- Sex Factors MeSH
- Stargardt Disease diagnosis genetics MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Multicenter Study MeSH
- Research Support, Non-U.S. Gov't MeSH
Next-generation sequencing (NGS) is increasingly used in transplantation settings, but also as a method of choice for in-depth analysis of population-specific HLA genetic architecture and its linkage to various diseases. With respect to complex ethnic admixture characteristic for East Croatian population, we aimed to investigate class-I (HLA-A, -B, -C) and class-II (HLA-DRB1, -DQA1, -DQB1) HLA diversity at the highest, 4-field resolution level in 120 healthy, unrelated, blood donor volunteers. Genomic DNA was extracted and HLA genotypes of class I and DQA1 genes were defined in full-length, -DQB1 from intron 1 to 3' UTR, and -DRB1 from intron 1 to intron 4 (Illumina MiSeq platform, Omixon Twin algorithms, IMGT/HLA release 3.30.0_5). Linkage disequilibrium statistics, Hardy-Weinberg departures, and haplotype frequencies were inferred by exact tests and iterative Expectation-Maximization algorithm using PyPop 0.7.0 and Arlequin v3.5.2.2 software. Our data provide first description of 4-field allele and haplotype frequencies in Croatian population, revealing 192 class-I and class-II alleles and extended haplotypic combinations not apparent from the existing 2-field HLA reports from Croatia. This established reference database complements current knowledge of HLA diversity and should prove useful in future population studies, transplantation settings, and disease-associated HLA screening.
- MeSH
- White People genetics MeSH
- Blood Donors MeSH
- Adult MeSH
- Gene Frequency MeSH
- Haplotypes MeSH
- HLA-A Antigens genetics MeSH
- HLA-B Antigens genetics MeSH
- HLA-C Antigens genetics MeSH
- HLA-DQ alpha-Chains genetics MeSH
- HLA-DQ beta-Chains genetics MeSH
- HLA-DRB1 Chains genetics MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Sequence Analysis, DNA MeSH
- Linkage Disequilibrium MeSH
- High-Throughput Nucleotide Sequencing MeSH
- Healthy Volunteers MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Croatia MeSH
One hundred and eighty Czech individuals from the Czech Republic pop 3 were genotyped at the HLA-DRB1, -DQA1 and -DQB1 loci using sequence-specific primers PCR methods. HLA-DRB1, -DQA1 and -DQB1 genotypes are consistent with expected Hardy-Weinberg (HW) proportions. These genotype data are available in the Allele Frequencies Net Database under identifier AFND.
- MeSH
- Alleles MeSH
- Gene Frequency MeSH
- Genotype * MeSH
- Haplotypes MeSH
- HLA-DQ alpha-Chains genetics MeSH
- HLA-DQ beta-Chains genetics MeSH
- HLA-DRB1 Chains genetics MeSH
- Humans MeSH
- Genetics, Population * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Czech Republic MeSH
Polymorphic genes with immune functions, namely those of the human leukocyte antigen (HLA) system, have been implicated in sarcoidosis pathogenesis. As HLA polymorphisms in sarcoidosis have not been yet investigated in the Korean population, we used next-generation sequencing (NGS), allowing detailed characterization of HLA alleles to investigate the role of HLA variation in Korean sarcoidosis patients. We enrolled 103 patients diagnosed by the ATS/ERS/WASOG guidelines at Asan Medical Centre, Seoul, Korea. Among those, genotyping of 7 HLA loci (HLA-A, -B, -C, -DQA1, -DQB1, -DRB1, -DPB1) was performed using Omixon HolotypeTM kit and HLATwin softwareTM. HLA allele frequencies were compared with frequency data on healthy Koreans from the allelic frequency databases, and 4-digit characteristics of HLA genotyping were used. Associations were assessed by two-tailed Fischer's exact test with correction for multiple comparisons. Variants previously associated with sarcoidosis risk (HLA-C*03:04, HLA-DRB1*12:01, HLA-DRB1*14:54) and a known protective variant HLA-DPB1*04:01, were associated with sarcoidosis in Koreans. Further, we suggest new HLA variants associated with sarcoidosis risk (e.g., HLA-DQA1*05:08) and novel protective variants HLA-DQB1*03:02 and HLA-DQA1*01:02 in Koreans. This first study of HLA variation in Korean patients with sarcoidosis by precise genotyping methodology reports data that could serve future meta-analyses on HLA variation's role in sarcoidosis.
Allelic variability in the adaptive immune receptor loci, which harbor the gene segments that encode B cell and T cell receptors (BCR/TCR), is of critical importance for immune responses to pathogens and vaccines. Adaptive immune receptor repertoire sequencing (AIRR-seq) has become widespread in immunology research making it the most readily available source of information about allelic diversity in immunoglobulin (IG) and T cell receptor (TR) loci. Here, we present a novel algorithm for extrasensitive and specific variable (V) and joining (J) gene allele inference, allowing the reconstruction of individual high-quality gene segment libraries. The approach can be applied for inferring allelic variants from peripheral blood lymphocyte BCR and TCR repertoire sequencing data, including hypermutated isotype-switched BCR sequences, thus allowing high-throughput novel allele discovery from a wide variety of existing data sets. The developed algorithm is a part of the MiXCR software. We demonstrate the accuracy of this approach using AIRR-seq paired with long-read genomic sequencing data, comparing it to a widely used algorithm, TIgGER. We applied the algorithm to a large set of IG heavy chain (IGH) AIRR-seq data from 450 donors of ancestrally diverse population groups, and to the largest reported full-length TCR alpha and beta chain (TRA and TRB) AIRR-seq data set, representing 134 individuals. This allowed us to assess the genetic diversity within the IGH, TRA, and TRB loci in different populations and to establish a database of alleles of V and J genes inferred from AIRR-seq data and their population frequencies with free public access through VDJ.online database.
- MeSH
- Alleles * MeSH
- Algorithms * MeSH
- Genetic Variation MeSH
- Humans MeSH
- Receptors, Antigen, B-Cell genetics immunology MeSH
- Receptors, Antigen, T-Cell genetics immunology MeSH
- Sequence Analysis, DNA methods MeSH
- Software * MeSH
- High-Throughput Nucleotide Sequencing methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
