Histogenetics

Ossining, NY, United States

Histogenetics

Ossining, NY, United States
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Robinson J.,Anthony Nolan Research Institute | Robinson J.,University College London | Guethlein L.A.,Stanford University | Cereb N.,Histogenetics | And 5 more authors.
PLoS Genetics | Year: 2017

HLA class I glycoproteins contain the functional sites that bind peptide antigens and engage lymphocyte receptors. Recently, clinical application of sequence-based HLA typing has uncovered an unprecedented number of novel HLA class I alleles. Here we define the nature and extent of the variation in 3,489 HLA-A, 4,356 HLA-B and 3,111 HLA-C alleles. This analysis required development of suites of methods, having general applicability, for comparing and analyzing large numbers of homologous sequences. At least three amino-acid substitutions are present at every position in the polymorphic α1and α2domains of HLA-A, -B and -C. A minority of positions have an incidence >1% for the ‘second’ most frequent nucleotide, comprising 70 positions in HLA-A, 85 in HLA-B and 54 in HLA-C. The majority of these positions have three or four alternative nucleotides. These positions were subject to positive selection and correspond to binding sites for peptides and receptors. Most alleles of HLA class I (>80%) are very rare, often identified in one person or family, and they differ by point mutation from older, more common alleles. These alleles with single nucleotide polymorphisms reflect the germ-line mutation rate. Their frequency predicts the human population harbors 8–9 million HLA class I variants. The common alleles of human populations comprise 42 core alleles, which represent all selected polymorphism, and recombinants that have assorted this polymorphism. © 2017 Robinson et al.


PubMed | University of California at San Francisco, University of Oxford and Histogenetics
Type: Journal Article | Journal: PLoS computational biology | Year: 2016

Genetic variation at the Human Leucocyte Antigen (HLA) genes is associated with many autoimmune and infectious disease phenotypes, is an important element of the immunological distinction between self and non-self, and shapes immune epitope repertoires. Determining the allelic state of the HLA genes (HLA typing) as a by-product of standard whole-genome sequencing data would therefore be highly desirable and enable the immunogenetic characterization of samples in currently ongoing population sequencing projects. Extensive hyperpolymorphism and sequence similarity between the HLA genes, however, pose problems for accurate read mapping and make HLA type inference from whole-genome sequencing data a challenging problem. We describe how to address these challenges in a Population Reference Graph (PRG) framework. First, we construct a PRG for 46 (mostly HLA) genes and pseudogenes, their genomic context and their characterized sequence variants, integrating a database of over 10,000 known allele sequences. Second, we present a sequence-to-PRG paired-end read mapping algorithm that enables accurate read mapping for the HLA genes. Third, we infer the most likely pair of underlying alleles at G group resolution from the IMGT/HLA database at each locus, employing a simple likelihood framework. We show that HLA*PRG, our algorithm, outperforms existing methods by a wide margin. We evaluate HLA*PRG on six classical class I and class II HLA genes (HLA-A, -B, -C, -DQA1, -DQB1, -DRB1) and on a set of 14 samples (3 samples with 2 x 100bp, 11 samples with 2 x 250bp Illumina HiSeq data). Of 158 alleles tested, we correctly infer 157 alleles (99.4%). We also identify and re-type two erroneous alleles in the original validation data. We conclude that HLA*PRG for the first time achieves accuracies comparable to gold-standard reference methods from standard whole-genome sequencing data, though high computational demands (currently ~30-250 CPU hours per sample) remain a significant challenge to practical application.


Fakhoury H.A.,King Saud bin Abdulaziz University for Health Sciences | Jawdat D.,King Abdullah International Medical Research Center | Alaskar A.S.,King Abdullah International Medical Research Center | Al Jumah M.,King Abdullah International Medical Research Center | And 3 more authors.
International Journal of Immunogenetics | Year: 2014

In this report, we present two novel HLA-A alleles: HLA-A*02:433 and HLA-A*02:434. These alleles were identified by sequence-based typing method (SBT), in two donors for the Saudi Bone Marrow Donor Registry (SBMDR). Allele A*02:433 is identical to A*02:05:01G except for a G to A substitution at nucleotide position 449 in exon 2. This substitution results in glycine to serine substitution at position 83. Whereas, allele A*02:434 is identical to A*02:01:01G except for a C to A substitution at nucleotide position 245 in exon 2, which results in phenylalanine to threonine substitution at position 15. The generation of both alleles appears to be the result of nucleotide point mutation involving 02:01:01 and 02:05:01. © 2014 John Wiley & Sons Ltd.


Fakhoury H.A.,King Saud bin Abdulaziz University for Health Sciences | Cereb N.,Histogenetics | Jawdat D.,King Abdullah International Medical Research Center | Al Jumah M.,King Abdullah International Medical Research Center | And 3 more authors.
International Journal of Immunogenetics | Year: 2014

Two new HLA- DRB1 alleles were identified by sequence-based typing method (SBT) in 1100 participants in the Saudi Stem Cell Donor Registry. HLA-DRB1*11:150 differs from HLA-DRB1*11:01:01G by a single C to A substitution at nucleotide position 5580 in exon 2, resulting in an amino acid change from alanine to glutamic acid at position 74. HLA-DRB1*14:145 differs from HLA-DRB1*14:04 by a C to G substitution at nucleotide position 5511 in exon 2, resulting in an amino acid change from threonine to arginine at position 51. © 2014 John Wiley & Sons Ltd.


Fakhoury H.A.,King Saud bin Abdulaziz University for Health Sciences | Jawdat D.,King Abdullah International Medical Research Center | Alaskar A.S.,King Abdullah International Medical Research Center | Al Jumah M.,King Abdullah International Medical Research Center | And 3 more authors.
International Journal of Immunogenetics | Year: 2015

Three new HLA-C alleles were identified by sequence-based typing method (SBT) in donors for the Saudi Bone Marrow Donor Registry (SBMDR). HLA-C*14:02:13 differs from HLA-C*14:02:01 by a silent G to A substitution at nucleotide position 400 in exon 2, where lysine at position 66 remains unchanged. HLA-C*15:72 differs from HLA-C*15:22 by a nonsynonymous C to A substitution at nucleotide position 796 in exon 3, resulting in an amino acid change from phenylalanine to leucine at position 116. HLA-C*15:74 differs from HLA-C*15:08 by a nonsynonymous C to T substitution at nucleotide position 914 in exon 3, resulting in an amino acid change from arginine to tryptophan at position 156. © 2015 John Wiley & Sons Ltd.


PubMed | King Saud bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center and Histogenetics
Type: Journal Article | Journal: International journal of immunogenetics | Year: 2015

Three new HLA-C alleles were identified by sequence-based typing method (SBT) in donors for the Saudi Bone Marrow Donor Registry (SBMDR). HLA-C*14:02:13 differs from HLA-C*14:02:01 by a silent G to A substitution at nucleotide position 400 in exon 2, where lysine at position 66 remains unchanged. HLA-C*15:72 differs from HLA-C*15:22 by a nonsynonymous C to A substitution at nucleotide position 796 in exon 3, resulting in an amino acid change from phenylalanine to leucine at position 116. HLA-C*15:74 differs from HLA-C*15:08 by a nonsynonymous C to T substitution at nucleotide position 914 in exon 3, resulting in an amino acid change from arginine to tryptophan at position 156.


PubMed | Instituto do Coracao, Histogenetics., Vanderbilt University, Childrens National Medical Center and 2 more.
Type: Journal Article | Journal: Global cardiology science & practice | Year: 2015

Endomyocardial fibrosis (EMF) is the most common form of restrictive cardiomyopathy worldwide. It has been linked to poverty and various environmental factors, but-for unknown reasons-only some people who live in similar conditions develop the disease. EMF cases cluster within both families and ethnic groups, suggesting a role for a genetic factor in host susceptibility. The human leukocyte antigen (HLA) system is associated with predisposition to various diseases. This two-center study was designed to investigate variation in the HLA system between EMF patients and unaffected controls. We provide the first genetic investigation of patients with EMF, as well as a comprehensive review of the literature.HLA class I (HLA-A, -B, -C) and class II (DRB1, DQB1) types were determined in 71 patients with severe EMF and 137 controls from Uganda and Mozambique. Chi Square analysis was used to identify any significant difference in frequency of class I and class II HLA types between cases and controls.Compared to ethnically matched controls, HLA-B*58 occurred more frequently in Mozambique patients with EMF and HLA-A*02:02 occurred more frequently in Ugandan patients with EMF.Ample subjective evidence in the historical literature suggests the importance of a genetically susceptible host in EMF development. In this first formal genetic study, we found HLA alleles associated with cases of EMF in two populations from sub-Saharan Africa, with EMF patients being more likely than controls to have the HLA-B*58 allele in Mozambique (p-0.03) and the HLA-A*02:02 in Uganda (p=0.005). Further investigations are needed to more fully understand the role of genetics in EMF development.


Schmidt A.H.,German Bone Marrow Donor Center | Schmidt A.H.,DKMS Life Science Laboratory | Solloch U.V.,German Bone Marrow Donor Center | Pingel J.,German Bone Marrow Donor Center | And 7 more authors.
PLoS ONE | Year: 2013

Regional HLA frequency differences are of potential relevance for the optimization of stem cell donor recruitment. We analyzed a very large sample (n = 123,749) of registered Polish stem cell donors. Donor figures by 1-digit postal code regions ranged from n = 5,243 (region 9) to n = 19,661 (region 8). Simulations based on region-specific haplotype frequencies showed that donor recruitment in regions 0, 2, 3 and 4 (mainly located in the south-eastern part of Poland) resulted in an above-average increase of matching probabilities for Polish patients. Regions 1, 7, 8, 9 (mainly located in the northern part of Poland) showed an opposite behavior. However, HLA frequency differences between regions were generally small. A strong indication for regionally focused donor recruitment efforts can, therefore, not be derived from our analyses. Results of haplotype frequency estimations showed sample size effects even for sizes between n≈5,000 and n≈20,000. This observation deserves further attention as most published haplotype frequency estimations are based on much smaller samples. © 2013 Schmidt et al.


PubMed | Histogenetics
Type: Journal Article | Journal: Human immunology | Year: 2015

This communication describes our experience in large-scale G group-level high resolution HLA typing using three different DNA sequencing platforms - ABI 3730 xl, Illumina MiSeq and PacBio RS II. Recent advances in DNA sequencing technologies, so-called next generation sequencing (NGS), have brought breakthroughs in deciphering the genetic information in all living species at a large scale and at an affordable level. The NGS DNA indexing system allows sequencing multiple genes for large number of individuals in a single run. Our laboratory has adopted and used these technologies for HLA molecular testing services. We found that each sequencing technology has its own strengths and weaknesses, and their sequencing performances complement each other. HLA genes are highly complex and genotyping them is quite challenging. Using these three sequencing platforms, we were able to meet all requirements for G group-level high resolution and high volume HLA typing.

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