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Microdeletions and gross deletions are important causes (~20%) of human inherited disease and their genomic locations are strongly influenced by the local DNA sequence environment. This notwithstanding, no study has systematically examined their underlying generative mechanisms. Here, we obtained 42,098 pathogenic microdeletions and gross deletions from the Human Gene Mutation Database (HGMD) that together form a continuum of germline deletions ranging in size from 1bp to 28,394,429bp. We analyzed the DNA sequence within 1-kb of the breakpoint junctions and found that the frequencies of non-B DNA-forming repeats, GC-content, and the presence of seven of 78 specific sequence motifs in the vicinity of pathogenic deletions correlated with deletion length for deletions of length ≤30 bp. Further, we found that the presence of DR, GQ and STR repeats is important for the formation of longer deletions (>30 bp) but not for the formation of shorter deletions (≤30 bp) whilst significantly (Chi-square test P-value30 bp). We provide evidence to support a functional distinction between microdeletions and gross deletions. Finally, we propose that a deletion length cut-off of 25-30bp may serve as an objective means to functionally distinguish microdeletions from gross deletions.

Background and Motivation: Whilst DNA repeat expansions cause numerous heritable human disorders, their origins and underlying pathological mechanisms are often unclear.Method: We collated a dataset comprising 224 human repeat expansions encompassing 203 different genes, and performed a systematic analysis with respect to key features at the DNA-, RNA- and protein-levels. Comparison with controls without known pathogenicity and genomic regions lacking repeats, allowed the construction of the first model to discriminate repeat regions harboring pathogenic repeat expansions (DPREx).Results: At the DNA level, pathogenic repeat expansions exhibited stronger signals for DNA regulatory factors (e.g. H3K4me3, transcription factor-binding sites) in exons, promoters, 5’UTRs, and 5’genes but not significantly different in introns, 3’UTRs and 3’genes than controls. At the RNA-level, pathogenic repeat expansions showed lower free energy for forming RNA secondary structure and were closer to splice sites in introns, exons, promoters and 5’genes than controls. At the protein level, pathogenic repeat expansions preferred to form coil than other types of secondary structures, and tended to encode surface-located protein domains. Additionally, pathogenic repeat expansions were also enriched in non-B DNA structures. Guided by these features, DPREx (http://biomed.nscc-gz.cn/zhaolab/geneprediction/#/) achieved an Area Under the Curve (AUC) value of 0.88 in an independent dataset test. Conclusion: Pathogenic repeat expansions are located so as to exert a synergistic, multi-level influence on stress responses and inter-molecular connections involving DNA, RNA and proteins, thereby impacting the relationship between genotype and clinical phenotype.

The Human Gene Mutation Database (HGMD®) constitutes a comprehensive collection of published germline mutations in nuclear genes that underlie, or are closely associated with human inherited disease. At the time of writing (March 2017), the database contained in excess of 203,000 different gene lesions identified in over 8000 genes manually curated from over 2600 journals. With new mutation entries currently accumulating at a rate exceeding 17,000 per annum, HGMD represents de facto the central unified gene/disease-oriented repository of heritable mutations causing human genetic disease used worldwide by researchers, clinicians, diagnostic laboratories and genetic counsellors, and is an essential tool for the annotation of next-generation sequencing data. The public version of HGMD (http://www.hgmd.org) is freely available to registered users from academic institutions and non-profit organisations whilst the subscription version (HGMD Professional) is available to academic, clinical and commercial users under license via QIAGEN Inc.

The Human Gene Mutation Database (HGMD®) is a comprehensive collection of germline mutations in nuclear genes that underlie, or are associated with, human inherited disease. By June 2013, the database contained over 141,000 different lesions detected in over 5,700 different genes, with new mutation entries currently accumulating at a rate exceeding 10,000 per annum. HGMD was originally established in 1996 for the scientific study of mutational mechanisms in human genes. However, it has since acquired a much broader utility as a central unified disease-oriented mutation repository utilized by human molecular geneticists, genome scientists, molecular biologists, clinicians and genetic counsellors as well as by those specializing in biopharmaceuticals, bioinformatics and personalized genomics. The public version of HGMD (http://www.hgmd.org) is freely available to registered users from academic institutions/non-profit organizations whilst the subscription version (HGMD Professional) is available to academic, clinical and commercial users under license via BIOBASE GmbH.

We have assessed the numbers of potentially deleterious variants in the genomes of apparently healthy humans by using (1) low-coverage whole-genome sequence data from 179 individuals in the 1000 Genomes Pilot Project and (2) current predictions and databases of deleterious variants. Each individual carried 281–515 missense substitutions, 40–85 of which were homozygous, predicted to be highly damaging. They also carried 40–110 variants classified by the Human Gene Mutation Database (HGMD) as disease-causing mutations (DMs), 3–24 variants in the homozygous state, and many polymorphisms putatively associated with disease. Whereas many of these DMs are likely to represent disease-allele-annotation errors, between 0 and 8 DMs (0–1 homozygous) per individual are predicted to be highly damaging, and some of them provide information of medical relevance. These analyses emphasize the need for improved annotation of disease alleles both in mutation databases and in the primary literature; some HGMD mutation data have been recategorized on the basis of the present findings, an iterative process that is both necessary and ongoing. Our estimates of deleterious-allele numbers are likely to be subject to both overcounting and undercounting. However, our current best mean estimates of ∼400 damaging variants and ∼2 bona fide disease mutations per individual are likely to increase rather than decrease as sequencing studies ascertain rare variants more effectively and as additional disease alleles are discovered.

Genes are nonrandomly distributed in the human genome, both within and between chromosomes. Thus, genes of similar function and common evolutionary origin are often clustered, as are genes with similar expression profiles. We now report that the >2400 genes known to underlie human monogenic inherited disease are non-randomly distributed in the genome over and above the general nonrandomness evident in the distribution of human genes. Further, a subset of 315 inherited disease genes subject to gross deletion was found to exhibit a degree of clustering that was twice that manifested by disease genes in general. The clustering of human disease genes is likely to have important implications for understanding the genotype-phenotype relationship in contiguous gene syndromes as well as those conditions characterized by multigene deletions or complex chromosomal rearrangements.

The rhesus macaque ( Macaca mulatta ) is an abundant primate species that diverged from the ancestors of Homo sapiens about 25 million years ago. Because they are genetically and physiologically similar to humans, rhesus monkeys are the most widely used nonhuman primate in basic and applied biomedical research. We determined the genome sequence of an Indian-origin Macaca mulatta female and compared the data with chimpanzees and humans to reveal the structure of ancestral primate genomes and to identify evidence for positive selection and lineage-specific expansions and contractions of gene families. A comparison of sequences from individual animals was used to investigate their underlying genetic diversity. The complete description of the macaque genome blueprint enhances the utility of this animal model for biomedical research and improves our understanding of the basic biology of the species.

Translocations and gross deletions are important causes of both cancer and inherited disease. Such gene rearrangements are nonrandomly distributed in the human genome as a consequence of selection for growth advantage and/or the inherent potential of some DNA sequences to be frequently involved in breakage and recombination. Using the Gross Rearrangement Breakpoint Database [GRaBD; www.uwcm.ac.uk/uwcm/mg/grabd/grabd.html] (containing 397 germ-line and somatic DNA breakpoint junction sequences derived from 219 different rearrangements underlying human inherited disease and cancer), we have analyzed the sequence context of translocation and deletion breakpoints in a search for general characteristics that might have rendered these sequences prone to rearrangement. The oligonucleotide composition of breakpoint junctions and a set of reference sequences, matched for length and genomic location, were compared with respect to their nucleotide composition. Deletion breakpoints were found to be AT-rich whereas by comparison, translocation breakpoints were GC-rich. Alternating purine-pyrimidine sequences were found to be significantly over-represented in the vicinity of deletion breakpoints while polypyrimidine tracts were over-represented at translocation breakpoints. A number of recombination-associated motifs were found to be over-represented at translocation breakpoints (including DNA polymerase pause sites/frameshift hotspots, immunoglobulin heavy chain class switch sites, heptamer/nonamer V(D)J recombination signal sequences, translin binding sites, and the chi element) but, with the exception of the translin-binding site and immunoglobulin heavy chain class switch sites, none of these motifs were over-represented at deletion breakpoints. Alu sequences were found to span both breakpoints in seven cases of gross deletion that may thus be inferred to have arisen by homologous recombination. Our results are therefore consistent with a role for homologous unequal recombination in deletion mutagenesis and a role for nonhomologous recombination in the generation of translocations.

A relatively rare type of mutation causing human genetic disease is the indel, a complex lesion that appears to represent a combination of micro-deletion and micro-insertion. In the absence of meta-analytical studies of indels, the mutational mechanisms underlying indel formation remain unclear. Data from the Human Gene Mutation Database (HGMD) were therefore used to compare and contrast 211 different indels underlying genetic disease in an attempt to deduce the processes responsible for their genesis. Each indel was treated as if it were the result of a two-step insertion/deletion process and was assessed in the context of 10 base-pairs DNA sequence flanking the lesion on either side. Several indel hotspots were noted and a GTAAGT motif was found to be significantly over-represented in the vicinity of the indels studied. Previously postulated mechanisms underlying micro-deletions and micro-insertions were initially explored in terms of local DNA sequence regularity as measured by its complexity. The change in complexity consequent to a mutation was found to be indicative of the type of repeat sequence involved in mediating the event, thereby providing clues as to the underlying mutational mechanism. Complexity analysis was then employed to examine the possible intermediates through which each indel could have occurred and to propose likely mechanisms and pathways for indel generation on an individual basis. Manual analysis served to confirm that the majority of indels (>90%) are explicable in terms of a two-step process involving established mutational mechanisms. Indels equivalent to double base-pair substitutions (22% of the total) were found to be mechanistically indistinguishable from the remainder and may therefore be regarded as a special type of indel. The observed correspondence between changes in local DNA sequence complexity and the involvement of specific mutational mechanisms in the insertion/deletion process, and the ability of generated models to account for both the number and identity of the bases deleted and/or inserted, makes this approach invaluable not only for the analysis of indel formation, but also for the study of other types of complex lesion.

Although 20 years have elapsed since the first single basepair substitution underlying an inherited disease in humans was characterised at the DNA level, the initiative has only recently been taken to establish central database resources for pathological genetic variants. Disease-associated gene lesions are currently collected and publicised by the Human Gene Mutation Database (HGMD) in Cardiff, locus-specific mutation databases, and to some extent also by the Genome Database (GDB) and Online Mendelian Inheritance in Man (OMIM). To date, HGMD represents the only comprehensive and publicly available database of gene lesions underlying human inherited disease. By July 1999, HGMD contained over 18,000 different mutations from some 900 human genes, the majority being single basepair substitutions. In addition to its potential as an information resource for clinicians and genetic counsellors, HGMD has allowed molecular geneticists to address a variety of biological questions through meta-analysis of the collated data. HGMD also promises to assist research workers in optimising mutation search strategies for a given gene. A questionnaire sent out to, and answered by, the editors of 20 key journals revealed that human genetics journals are increasingly reluctant to publish mutation reports. Electronic data submission and publication facilities are therefore urgently required. The World Wide Web (WWW) provides an excellent medium within which to combine the centralised management of basic mutation data, including rigorous quality control, with the possibility of publishing additional mutation-related information. In response to these needs, HGMD has both instituted a collaboration with Springer-Verlag GmbH, Heidelberg, to potentiate free online submission and electronic publication of human gene mutation data and developed links with the curators of locus-specific mutation databases.

We write in response to a number of very specific criticisms of the Human Gene Mutation Database (HGMD; www.hgmd.org) made in the recently published article by George et al ( see review on p 65 ).1 All seven claims made were amenable to empirical testing. Having tested these claims, we find all of them to be either false or highly misleading. In the text that follows, we refute or rebut each claim in turn. HGMD represents an attempt to collate known (published) gene lesions responsible for human inherited disease. HGMD comprises various types of germ-line mutation within the coding, splicing and regulatory regions of human nuclear genes. HGMD currently (1 December 2007) contains 76 011 different mutations in 2876 human genes. Claim 1: 143 genes are present in OMIM but have no corresponding HGMD entry Response —This claim is wholly misleading. OMIM (Online Mendelian Inheritance in Man) records many types of gene mutation which HGMD does not, such as somatic lesions, neutral polymorphisms and mitochondrial mutations. It is therefore to be expected that there will be some entries in OMIM that do not have a corresponding HGMD entry. We received the list of 143 genes from George et al and performed our own analysis. After careful comparison with OMIM, we found the following

The Human Gene Mutation Database (HGMD) constitutes a comprehensive core collection of data on germ-line mutations in nuclear genes underlying or associated with human inherited disease (http://www.hgmd.org). Data cataloged include single-base-pair substitutions in coding, regulatory, and splicing-relevant regions, micro-deletions and micro-insertions, indels, and triplet repeat expansions, as well as gross gene deletions, insertions, duplications, and complex rearrangements. Each mutation is entered into HGMD only once, in order to avoid confusion between recurrent and identical-by-descent lesions. By March 2012, the database contained in excess of 123,600 different lesions (HGMD Professional release 2012.1) detected in 4,514 different nuclear genes, with new entries currently accumulating at a rate in excess of 10,000 per annum. ∼6,000 of these entries constitute disease-associated and functional polymorphisms. HGMD also includes cDNA reference sequences for more than 98% of the listed genes.

A total of 405 unique single base-pair substitutions, located within the ATG translation initiation codons (TICs) of 255 different genes, and reported to cause human genetic disease, were retrieved from the Human Gene Mutation Database (HGMD). Although these lesions comprised only 0.7% of coding sequence mutations in HGMD, they nevertheless were 3.4-fold overrepresented as compared to other missense mutations. The distance between a TIC and the next downstream in-frame ATG codon was significantly greater for genes harboring TIC mutations than for the remainder of genes in HGMD (control genes). This suggests that the absence of an alternative ATG codon in the vicinity of a TIC increases the likelihood that a given TIC mutation will come to clinical attention. An additional 42 single base-pair substitutions in 37 different genes were identified in the vicinity of TICs (positions −6 to +4, comprising the so-called “Kozak consensus sequence”). These substitutions were not evenly distributed, being significantly more abundant at position +4. Finally, contrary to our initial expectation, the match between the original TIC and the Kozak consensus sequence was significantly better (rather than worse) for genes harboring TIC mutations than for the HGMD control genes.

International audience; The number of reported germline mutations in human nuclear genes, either underlying or associated with inherited disease, is set tohas now exceeded 100,000 in more than 3,7600 different genes. The availability of these data has both revolutionized the study of the morbid anatomy of the human genome and facilitated ‘personalized genomics'. With ~300 new ‘inherited disease genes' (and ~10,000 new mutations) being identified annually, it is pertinent to ask how many ‘inherited disease genes' there are there in the human genome, how many mutations reside within them and where are such lesions are likely to be located? To address these questions, it is necessary not only to reconsider how we define human genes but also to explore notions of gene ‘'essentiality'' and ‘dispensability'. Answers to these questions are now emerging from recent novel insights into genome structure and function and through complete genome sequence information derived from multiple individual human genomes. However, a change in focus towards screening functional genomic elements as opposed to genes sensu stricto will be required if we are to capitalize fully on recent technical and conceptual advances and identify new types of disease-associated mutation within non-coding regions remote from the genes whose function they disrupt.

The Human Gene Mutation Database (HGMD) constitutes a comprehensive core collection of data on germ-line mutations in nuclear genes underlying or associated with human inherited disease (www.hgmd.org). Data catalogued includes: single base-pair substitutions in coding, regulatory and splicing-relevant regions; micro-deletions and micro-insertions; indels; triplet repeat expansions as well as gross deletions; insertions; duplications; and complex rearrangements. Each mutation is entered into HGMD only once in order to avoid confusion between recurrent and identical-by-descent lesions. By March 2003, the database contained in excess of 39,415 different lesions detected in 1,516 different nuclear genes, with new entries currently accumulating at a rate exceeding 5,000 per annum. Since its inception, HGMD has been expanded to include cDNA reference sequences for more than 87% of listed genes, splice junction sequences, disease-associated and functional polymorphisms, as well as links to data present in publicly available online locus-specific mutation databases. Although HGMD has recently entered into a licensing agreement with Celera Genomics (Rockville, MD), mutation data will continue to be made freely available via the Internet.

No general rules have been proposed to account for the functional consequences of gene regulatory mutations. In a first attempt to establish the nature of such rules, an analysis was performed of the DNA sequence context of 153 different single base-pair substitutions in the regulatory regions of 65 different human genes underlying inherited disease. Use of a recently proposed measure of DNA sequence complexity (taking into account the level of structural repetitiveness of a DNA sequence, rather than simply the oligonucleotide composition) has served to demonstrate that the concomitant change in local DNA sequence complexity surrounding a substituted nucleotide is related to the likelihood of a regulatory mutation coming to clinical attention. Mutations that led to an increase in complexity exhibited higher odds ratios in favour of pathological consequences than mutations that led to a decrease or left complexity unchanged. This relationship, however, was discernible only for pyrimidine-to-purine transversions. Odds ratios for other types of substitution were not found to be significantly associated with local changes in sequence complexity, even though a trend similar to that observed for Y-->R transversions was also apparent for transitions. These findings suggest that the maintenance of a defined level of DNA sequence complexity, or at least the avoidance of an increase in sequence complexity, is a critical prerequisite for the function of gene regulatory regions.

The Human Gene Mutation Database (HGMD) represents a comprehensive core collection of data on published germline mutations in nuclear genes underlying human inherited disease. By September 1997, the database contained nearly 12 000 different lesions in a total of 636 different genes, with new entries currently accumulating at a rate of over 2000 per annum. Although originally established for the scientific study of mutational mechanisms in human genes, HGMD has acquired a much broader utility to researchers, physicians and genetic counsellors so that it was made publicly available at http://www.uwcm.ac.uk/uwcm/mg/hgmd0.html in April 1996. Mutation data in HGMD are accessible on the basis of every gene being allocated one web page per mutation type, if data of that type are present. Meaningful integration with phenotypic, structural and mapping information has been accomplished through bi-directional links between HGMD and both the Genome Database (GDB) and Online Mendelian Inheritance in Man (OMIM), Baltimore, USA. Hypertext links have also been established to Medline abstracts through Entrez, and to a collection of 458 reference cDNA sequences also used for data checking. Being both comprehensive and fully integrated into the existing bioinformatics structures relevant to human genetics, HGMD has established itself as the central core database of inherited human gene mutations.

Single base substitutions constitute the most frequent type of human gene mutation and are a leading cause of cancer and inherited disease. These alterations occur non-randomly in DNA, being strongly influenced by the local nucleotide sequence context. However, the molecular mechanisms underlying such sequence context-dependent mutagenesis are not fully understood. Using bioinformatics, computational and molecular modeling analyses, we have determined the frequencies of mutation at G•C bp in the context of all 64 5′-NGNN-3′ motifs that contain the mutation at the second position. Twenty-four datasets were employed, comprising >530,000 somatic single base substitutions from 21 cancer genomes, >77,000 germline single-base substitutions causing or associated with human inherited disease and 16.7 million benign germline single-nucleotide variants. In several cancer types, the number of mutated motifs correlated both with the free energies of base stacking and the energies required for abstracting an electron from the target guanines (ionization potentials). Similar correlations were also evident for the pathological missense and nonsense germline mutations, but only when the target guanines were located on the non-transcribed DNA strand. Likewise, pathogenic splicing mutations predominantly affected positions in which a purine was located on the non-transcribed DNA strand. Novel candidate driver mutations and tissue-specific mutational patterns were also identified in the cancer datasets. We conclude that electron transfer reactions within the DNA molecule contribute to sequence context-dependent mutagenesis, involving both somatic driver and passenger mutations in cancer, as well as germline alterations causing or associated with inherited disease., Author Summary A large number of DNA mutations identified in cells from patients with cancer or human inherited disease were analyzed to address a fundamental issue in human pathology, viz, the mutational mechanisms that cause irreversible changes to DNA. By using bioinformatics and computational methods, we found that mutations do not occur randomly, but instead affect specific bases, most often guanines flanked by other guanines or adenines. We attribute this effect to electron transfer, a chemical reaction known to underlie basic biological processes such as cellular respiration and photosynthesis. Certain types of carcinogens, oxidants or radiation can interact with DNA and abstract an electron. Our results imply that the ensuing sites of electron loss can migrate from their original position in the DNA to neighboring guanines where they become trapped, leading to further chemical modifications that may eventually result in mutations. Many of the mutations known to be important for tumor growth (driver mutations), as well as passenger mutations and mutations associated with inherited disease, appear to be caused by electron transfer. Beyond pathological mutations, electron transfer may represent a universal mechanism by which genetic changes occur in all life forms to drive population fitness over evolutionary time.

The recent publication of the draft genome sequences of the Neanderthal and a ~50,000-year-old archaic hominin from Denisova Cave in southern Siberia has ushered in a new age in molecular archaeology. We previously cross-compared the human, chimpanzee and Neanderthal genome sequences with respect to a set of disease-causing/disease-associated missense and regulatory mutations (Human Gene Mutation Database) and succeeded in identifying genetic variants which, although apparently pathogenic in humans, may represent a 'compensated' wild-type state in at least one of the other two species. Here, in an attempt to identify further 'potentially compensated mutations' (PCMs) of interest, we have compared our dataset of disease-causing/disease-associated mutations with their corresponding nucleotide positions in the Denisovan hominin, Neanderthal and chimpanzee genomes. Of the 15 human putatively disease-causing mutations that were found to be compensated in chimpanzee, Denisovan or Neanderthal, only a solitary F5 variant (Val1736Met) was specific to the Denisovan. In humans, this missense mutation is associated with activated protein C resistance and an increased risk of thromboembolism and recurrent miscarriage. It is unclear at this juncture whether this variant was indeed a PCM in the Denisovan or whether it could instead have been associated with disease in this ancient hominin.

The Human Gene Mutation Database (HGMD((R))) is a comprehensive core collection of germline mutations in nuclear genes that underlie or are associated with human inherited disease. Here, we summarize the history of the database and its current resources. By December 2008, the database contained over 85,000 different lesions detected in 3,253 different genes, with new entries currently accumulating at a rate exceeding 9,000 per annum. Although originally established for the scientific study of mutational mechanisms in human genes, HGMD has since acquired a much broader utility for researchers, physicians, clinicians and genetic counselors as well as for companies specializing in biopharmaceuticals, bioinformatics and personalized genomics. HGMD was first made publicly available in April 1996, and a collaboration was initiated in 2006 between HGMD and BIOBASE GmbH. This cooperative agreement covers the exclusive worldwide marketing of the most up-to-date (subscription) version of HGMD, HGMD Professional, to academic, clinical and commercial users.