Mutation@A Glance: an integrative web application for analysing mutations from human genetic diseases.

Abstract

Although mutation analysis serves as a key part in making a definitive diagnosis about a genetic disease, it still remains a time-consuming step to interpret their biological implications through integration of various lines of archived information about genes in question. To expedite this evaluation step of disease-causing genetic variations, here we developed Mutation@A Glance (http://rapid.rcai.riken.jp/mutation/), a highly integrated web-based analysis tool for analysing human disease mutations; it implements a user-friendly graphical interface to visualize about 40,000 known disease-associated mutations and genetic polymorphisms from more than 2600 protein-coding human disease-causing genes. Mutation@A Glance locates already known genetic variation data individually on the nucleotide and the amino acid sequences and makes it possible to cross-reference them with tertiary and/or quaternary protein structures and various functional features associated with specific amino acid residues in the proteins. We showed that the disease-associated missense mutations had a stronger tendency to reside in positions relevant to the structure/function of proteins than neutral genetic variations. From a practical viewpoint, Mutation@A Glance could certainly function as a 'one-stop' analysis platform for newly determined DNA sequences, which enables us to readily identify and evaluate new genetic variations by integrating multiple lines of information about the disease-causing candidate genes.

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Mutation@A Glance: An Integrative Web Application for Analysing
Mutations from Human Genetic Diseases
ATSUSHI Hijikata1, RAJESH Raju2,3,4, SHIVAKUMAR Keerthikumar2,3,4, SUBHASHRI Ramabadran2,3,
LAVANYA Balakrishnan2,3, SURESH KUMAR Ramadoss2, AKHILESH Pandey3,5, SUJATHA Mohan2,3, and
OSAMU Ohara1,6,*
Laboratory for Immunogenomics, RIKEN Research Center for Allergy and Immunology, 1-7-22 Suehiro-cho, Tsurumi-
ku, Yokohama, Kanagawa 230-0045, Japan1; Research Unit for Immunoinformatics, RIKEN Research Center for
Allergy and Immunology, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan2; Institute of
Bioinformatics, International Technology Park, Bangalore 560 066, India3; Department of Biotechnology and
Bioinformatics, Kuvempu University, Jnanasahyadri, Shimoga 577 451, India4; McKusick-Nathans Institute of
Genetic Medicine, Johns Hopkins University School of Medicine, 733 N. Broadway, BRB Room 527, Baltimore, MD
21205, USA5and Laboratory of Genome Technology, Department of Human Genome Research, Kazusa DNA
Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan6
*To whom correspondence should be addressed. Tel. þ81 45-503-9696. Fax. þ81 45-503-9694.
Email: oosamu@rcai.riken.jp
Edited by Katsumi Isono
(Received 17 January 2010; accepted 8 March 2010)
Abstract
Although mutation analysis serves as a key part in making a definitive diagnosis about a genetic disease,
it still remains a time-consuming step to interpret their biological implications through integration of
various lines of archived information about genes in question. To expedite this evaluation step of
disease-causing genetic variations, here we developed Mutation@A Glance (http://rapid.rcai.riken.jp/
mutation/), a highly integrated web-based analysis tool for analysing human disease mutations; it
implements a user-friendly graphical interface to visualize about 40 000 known disease-associated
mutations and genetic polymorphisms from more than 2600 protein-coding human disease-causing
genes. Mutation@A Glance locates already known genetic variation data individually on the nucleotide
and the amino acid sequences and makes it possible to cross-reference them with tertiary and/or quatern-
ary protein structures and various functional features associated with specific amino acid residues in the
proteins. We showed that the disease-associated missense mutations had a stronger tendency to reside in
positions relevant to the structure/function of proteins than neutral genetic variations. From a practical
viewpoint, Mutation@A Glance could certainly function as a ‘one-stop’ analysis platform for newly deter-
mined DNA sequences, which enables us to readily identify and evaluate new genetic variations by inte-
grating multiple lines of information about the disease-causing candidate genes.
Key words: genetic disease; mutation; polymorphism; bioinformatics; protein structure
1.Introduction
Genetic diseases are caused by structural changes
genesand/orchromosomes.
Mendelian Inheritance in Man (OMIM, http://www.
ncbi.nlm.nih.gov/sites/entrez?db=omim)
more than 2200 genes are known to have mutations
in Inthe Online
database,
causing genetic diseases.1
immunodeficiency diseases (PIDs) are caused by con-
genital defects in genes involved in the development
and maintenance of the immune system,2,3and
they can be diagnosed using mutation analysis that
identifies pathogenic mutations in candidate PID
genes. This process plays a critical role in improving
For instance, primary
#The Author 2010. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://
creativecommons.org/licenses/by-nc/2.5), which permits unrestricted non-commercial use, distribution, and reproduction in any medium,
provided the original work is properly cited.
DNA RESEARCH 17, 197–208, (2010)
Advance Access Publication: 1 April 2010
doi:10.1093/dnares/dsq010

Page 2

the quality of life for PID patients.4In this regard, the
recent advances in DNA sequencing technology will
extremely expedite this process. Thus, the next bottle-
neck to be addressed is obviously how to clarify the
associations between newly identified patient-specific
genetic variations and disease phenotypes, even when
familial disease history is absent. To eliminate the
bottleneck in mutation analysis, we need a bioinfor-
matics tool that would enable us to readily evaluate
the impact of a genetic variation on the structure/
function of a gene product at the molecular level.
Towards this end, our first step was to develop an inte-
grated ‘one-stop’ analysis platform where we could
cross-reference multiple lines of information regard-
ing known genetic variations, including a huge
amount of non-synonymous (ns) single-nucleotide
polymorphisms (nsSNPs) in healthy individuals,5–7
in genes of interest.
Bioinformatics resources and methods played an
indispensable role in creating this platform.8–12
Although a number of databases regarding reported
human disease mutations and SNPs have been
alreadyconstructed,13–25
launched as a static archive for genetic variation data,
not necessarily an interactive tool for evaluating
newly identified sequence variation data. Several com-
putational algorithms for predicting the effects of ns
substitutions on a corresponding protein have been
developed using evolutionary and protein three-
dimensional(3D)structure
However, despite public availability of these soft-
ware/web servers, there are at least two hurdles,
especially for clinical researchers to exploit them for
the mutation analysis: (i) since these servers usually
require information about the position of the genetic
variation occurred in a submitted sequence as a
queryinput,theusershavetospecify thevariationpos-
ition in the sequence before submitting the query; (ii)
since these servers do not necessarily incorporate
known disease-associated mutation data into their
systems, the users have to manually compare their
newly identified genetic variation data from patients
with previously reported data. Thus, we thought it
was important to integrate predictive bioinformatics
tools, such as the one described above, with a compre-
hensive set of known genetic variation data, to create a
‘one-stop’ mutation analysis platform.32
In this context, here we present Mutation@A
Glance (http://rapid.rcai.riken.jp/mutation/), a new
web-based integrated bioinformatics tool for analysing
mutations from human genetic diseases. The user-
friendly graphical interface of Mutation@A Glance
makes it possible to allocate known disease-associated
mutation data on the nucleotide and amino acid
sequences of a gene of interest, and to link these
mutation data to the 3D structure of the gene product
thesedatabases were
information.26–31
along with various lines of information about the
mutated amino acid residues (e.g. the extent of evolu-
tional sequence conservation, post-translational modi-
fications and molecular interactions). Furthermore,
this tool enables users to identify and evaluate newly
identifiedsequencevariationsinaqueryDNA sequence
from a gene of interest by comparing them with known
disease-associated mutation data and using the SIFT
program,26which is one of the most accurate and
widely used program to specifically predict the effects
of ns substitutions based on evolutionary information
for each residue position.33Therefore, Mutation@A
Glance surely serves as a ‘one-stop’ informational plat-
form to identify and evaluate new genetic variations
by integrating multiple lines of information about the
disease-causing candidate genes.
2. Materials and methods
2.1. Data resources for disease-associated genes and
sequence variations
Human disease-associated mutation data were
obtained from the following three databases: OMIM
(http://www.ncbi.nlm.nih.gov/omim/),1
(http://www.uniprot.org/)34and RAPID (http://rapid.
rcai.riken.jp/).17Sequence variations that were associ-
ated with OMIM in the dbSNP database (Build 130,
http://www.ncbi.nlm.nih.gov/projects/SNP/)18
considered to be disease-associated mutations and
other variations were considered non-disease associ-
ated. For the mutation data in the UniProt database,
VARIANT features associated with diseases in the
human entries were considered. RAPID is a molecular
database that we have recently established for
reported disease mutation data in genes causing
PIDs.17The RAPID database is directly connected to
our local server and the mutation data (as of August
2009) are retrieved using a Perl script. The human
genome sequence (Build 36.3), RefSeq sequences for
nucleotides and proteins of human were downloaded
from the NCBI ftp site (ftp://ftp.ncbi.nlm.nih.gov/).
Informationregardingresidue-wisefunctionalfeatures
(Transmembrane helix, signal peptide, nucleotide
binding, disulphide bond, metal binding, active site
and post-translational modification site) was extracted
from the human entries in the UniProt database.
Information regarding the exon–intron structures of
each gene was downloaded from the NCBI ftp site.
UniProt
were
2.2.Calculation of sequence conservation in ns
substitution sites
Homologous protein sequences in other organisms
to the human proteins encoded by disease-causing
genes were identified using the BLAST program35
against the RefSeq database (6 691 817 amino acid
198 Integrative Web Tool for Human Disease Mutation[Vol. 17,

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sequences) with a cut-off E-value of 1024. If the
sequence identity and the coverage between a
sequence hit and the human were higher than 40%
and 80%, respectively, the sequence was selected as
ahomologoussequence.
sequences from an organism were found as homolo-
gous sequences, the sequence with the highest
sequence identity was only considered. The homolo-
gous protein sequences from various organisms were
aligned using the CLUSTAL W program.36A degree of
sequence conservation at each amino acid position
in the multiple sequence alignment (simply desig-
nated as ‘residue conservation’ in Fig. 1) was defined
as the ratio of (the number of the homologous
protein sequences which carried an identical amino
acid residue to that in the human sequence) to
(the number of the aligned homologous protein
sequences) at the specified position in the multiple
sequence alignment. For example, if Ala appears in
an aligned position in the human sequence and the
corresponding positions in all of the other homolo-
gous sequences are also Ala, the residue conservation
in this position is defined as 1.0. The frequency distri-
bution of the residue conservations in disease-associ-
ated missense mutation or nsSNP positions for
proteins analysed in this study was represented
using bins of the interval of 0.2. The value in each
bin was normalized by the frequency of the total
number of residues in each bin.
When two ormore
2.3. Protein 3D structure information
Protein 3D structure data were downloaded from
the Protein Data Bank (PDB, http://www.rcsb.org/
pdb/).37In cases where the 3D structure of a
human protein had not yet been determined, we
searched the available sequences in the PDB entries
for a template structure for homology modelling
using the BLAST program as described above. When
the alignment of the human protein sequence and a
known 3D structure showed .30% identity and
.90% coverage, a homology model was built using
the MODELLER package.38For each target, 20 model
structures were generated and their reliabilities were
assessed with the Discrete Optimized Protein Energy
(DOPE) method.39Eventually, the model with the
best DOPE score was selected as the final model for
each protein. Information about protein quaternary
structures was also extracted from the PDB database.
Entries from the PDB that contained information
about the biological unit structure and entries with
polypeptide chains showed .85% identities with a
human protein sequence were considered. When a
distance of one atom in a residue in a given polypep-
tide chain was ,5.0 A˚from that of another residue in
the other polypeptide or nucleotide chain, the residue
was considered to be located at a molecular inter-
action interface.
2.4.Solvent accessibility calculations
The solvent accessibilities of the amino acid resi-
dues in a 3D modelled structure were calculated
using a modification of the Shrake and Rupley
method,40with a water molecule represented by a
1.4 A˚radius sphere. The solvent accessibility is rep-
resented by values ranging from 0 to 1. The residue
was considered as an exposed residue on the protein
surface, if the solvent accessibility was .0.25 and
buried otherwise.
2.5.Disorder prediction
We used the DISOPRED2 program41to analyse each
amino acid sequence of a gene product and predict
intrinsically unstructured (disordered) regions in the
protein sequence. If the program predicted a region
consisting of more than three amino acid residues in
a sequence to be ‘disordered’, we assigned this
region as an intrinsically unstructured one.
2.6.Predicting the effect of ns substitutions on proteins
The effects of ns substitutions on a given protein
were evaluated on a local server using the SIFT
program26which predicts the effects of missense sub-
stitutions on a protein based on evolutionary infor-
mation from homologous protein sequences.
2.7. System implementation
At the server end, a set of common gateway interface
programs was written in Perl and is running on an
Apache web server. The information regarding the
disease-associated genes and the sequence variations
Figure1. Comparison
conservations in disease-associated missense mutations and
nsSNPs. The vertical axis depicts the log-odds ratio of the
frequencyof nssubstitution
associated mutations or nsSNPs) to those of total number of
residues in each residue conservation bin.
offrequency distributionsof residue
residue positions(disease-
No. 3] A. Hijikata et al.199

Page 4

described above was integrated into a MySQL database
implemented in the server. At the client end, JavaScript
frameworkssuch as prototype.js
prototypejs.org/) and scriptaculous.js (http://script.
aculo.us/) were used to make the user interface
more interactive. Jmol, a Java applet (http://www.
jmol.org/), was implemented for visualizing protein
3D structures in a web browser.
(http://www.
3. Results and discussion
3.1.Statistics of the sequence variation data on
Mutation@A Glance
From three data resources for human disease
mutations, OMIM, UniProt and RAPID, we obtained
25 616 disease-associated mutations and 21 199
nsSNPs in 2656 human genes (Table 1) and inte-
grated into the local database. Functional classifi-
cation of the proteins encoded by the disease-
associated genes showed a wide variety of molecular
functionssuch asmetabolic
kinases, transcription factor/regulators and structural
proteins (Table 1 and Supplementary Table S1).
Because we have been actively analysing mutations
found in patients of PIDs with paediatricians in
Japan, we constructed RAPID and used it as our orig-
inal data resource for genetic variations in genes
responsible for PIDs.17
RAPID contains manually
curated mutation data from published literature,
including nonsense (582 sites in 96 genes), frame-
shift (851 sites in 101 genes) and insertion/deletion
(85 sites in 42 genes) mutations as well as missense
mutations (1564 sites in 116 genes) in the protein-
coding regions of 155 PID genes (as of August
2009). For non-PID genes, we used two publicly avail-
able data sets from UniProt and OMIM. The UniProt
database contains only missense mutation data
(22 258 entries in 2614 genes). On the other hand,
the OMIM database contains a large number of mis-
sense mutation (1899 entries in 556 genes) and a
relatively small number of the other types of
mutations (99 entries in 13 genes). The RAPID and
the OMIM databases also contain 699 disease-associ-
ated mutation data in intronic regions of 147 genes
that cause splice anomaly effects. Thus, the most fre-
quent mutation type in our data sets was missense
mutation (89% of the total entry) as reported in the
previous study.13
enzymes, protein
3.2.Evolutionary, structural and functional features of
the ns substitution positions
In general, disease-associated missense mutations
tend to occur at evolutionarily conserved positions,
because these positions are usually essential for the
structure and/or function of a protein.26,42,43To
verify this using the up-dated data set, we compared
the frequencyof disease-associated
mutation sites (19 128 unique positions in 2622
genes) in each residue conservation bin with that of
nsSNP sites (20 605 positions in 2494 genes)
(Fig. 1). The results indicated that the previously
reported tendency was still true for the 2622 genes
in our data set; the disease-associated mutation sites
were preferably appeared in the highest residue con-
servation bin, while nsSNP sites showed the opposite
trend (Fig. 1). Next, we cross-referenced amino acid
positions of the disease-associated
mutations and nsSNPs to the functional features and
3D structures of the protein data in Mutation@A
Glance. We classified these positions in terms of
their functional features in a protein (annotated in
the UniProt databases; Table 2). More disease-associ-
ated missense mutations were found in the positions
annotated to have some functional features, except
in the ‘signal peptides’ and ‘post-translational modifi-
cation sites’, than nsSNPs. Using a homology model-
ling technique, we mapped 10 939 out of 19 128
missense
missense
Table
products
1. Functional classificationof disease-associatedgene
Molecular class No. of
genes
410
258
239
No. of mutationsa
No. of
nsSNPs
2476
2452
1502
Enzymes
Protein kinases
Transcription factor/
regulator
Structural proteins
Cell surface receptors
Transport/cargo
protein
DNA/RNA binding
proteins
Integral membrane
protein
Channels
GTPase/GTPase
regulators
Membrane transport
protein
Immunity proteins
Extracellular matrix
protein
Proteases
Cell adhesion
molecules
Others
Unclassified
Total
5406 (5003)
1947 (1340)
2889 (2743)
132
123
116
1588 (1377)
1271 (1165)
1617 (1411)
1800
838
1139
97 429 (369)580
87 446 (434) 698
79
71
958 (948)
371 (351)
639
450
67755 (751)523
58
53
496 (183)
886 (884)
423
939
53
52
345 (284)
390 (363)
368
428
430
331
2656
4647 (4091)
1175 (987)
25 616 (22 684)
3863
2081
21 199
aThe numbers in parentheses indicate the number of
disease-associated missense mutations.
200 Integrative Web Tool for Human Disease Mutation[Vol. 17,

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disease-associated mutation sites (57.2%) to protein
3D structures (Fig. 2). Of these sites, 6616 sites
(60.4%) were located in regions buried in protein
structures (solvent accessibility ,0.25). In the same
way, 7106 out of 20 605 nsSNP sites (34.4%) were
mapped to 3D structures, and 4258 sites (59.9%)
were located on the surfaces of proteins (Fig. 2A).
This observation is basically consistent with the
previousfindingsfrom
Interestingly, nsSNP sites were located in regions
predicted as intrinsically disordered at a three times
higher frequency than disease-associated mutation
sites (Fig. 2A). This might be ascribed to the
observation that conservation in the intrinsically
disordered regions is relatively lower than that in
ordered regions.47
Proteinsfunctionwith
molecular networks (e.g. signalling pathways) in
many cases. Hence, the effects of mutations on mol-
ecular interactions must be intriguing in mutation
structuralanalysis.44–46
other molecules in
Table 2. Structural and functional loci of mutation/nsSNP sites
Property
Transmembrane helix
Nucleotide binding
Disulfide bond
Metal binding site
Signal peptide
Post translational modification site
Binding sitea
Active sitea
Disease mutations
1283
670
385
226
101
97
48
25
nsSNPs
648
102
39
147
262
104
12
6
aAs defined in UniProt database (described in the text).
Figure 2. Classification of disease-associated mutations and nsSNPs according to their location on protein 3D structure. (A) The numbers in
the pie charts depict those of ns substitution positions. (B) Proportion of ns substitution positions in the disease-associated mutations or
nsSNPs that were located on the interface of the experimentally determined quaternary structures.
No. 3]A. Hijikata et al.201

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analysis.48We thus analysed whether or not the mis-
sense mutation positions were located in the molecu-
lar interaction sites based on the quaternary protein
structures available from the PDB. Consequently,
714 out of 1738 disease-associated mutation sites
(41.1%) were found to locate at the interfaces of
474 distinct proteins known to be involved in
protein complex structures (Fig. 2B; see Section 2.3).
In contrast, the same was true for only 346 out of
1128 nsSNP sites (30.7%) in 447 genes. We con-
firmed that the frequency of disease-associated
mutation sites located at the molecular interaction
interface was significantly higher than that of nsSNP
sites by x2test (P, 0.01). These results implicated
that ns substitutions at positions involved in the
molecular interaction tend to be disease-related as
we expected.
3.3.The user interface for visualizing sequence
variations
Figure 3 shows the front page of the Mutation@A
Glance website. It has two types of query forms, for
visualizing known disease mutation data (Fig. 3A)
and for evaluating novel genetic variations in query
DNA sequences (Fig. 3B). For the visualization, a user
inputs a given gene symbol of interest in the form.
When the user enters some characters in the form, a
list of gene names containing the input character
string is shown to assist the user input. In addition, a
user can also search for the gene name of interest
from an entire list of genes available in Mutation@A
Glance, which is displayed by clicking ‘Select from
List’ button (Fig. 3A). Just as information for users,
the mutation data set used for each gene is noted
near the ‘Select from List’ button. Figure 4 shows
Figure 3. The front page of Mutation@A Glance. There are two types of query interface for (A) browsing known mutation data and (B)
evaluating novel sequence variations in DNA sequences of interest. See the main text for details of the mutation data available in
Mutation@A Glance.
202Integrative Web Tool for Human Disease Mutation [Vol. 17,

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sample screenshots for the STAT3 gene, which is
known to be causative to
(HIES).49,50
At the DNA level, positions of the
disease-associated mutations, including substitution,
insertion and deletion, as well as SNPs are shown on
a set of exon sequences or genomic DNA sequence
with/without the open-reading frame for the gene
of interest (Fig. 4A). If two or more alternative
transcripts exist in the RefSeq database, the genetic
variation data are allocated on the reference sequence
hyper-IgEsyndrome
that encodes the longest amino acid sequence among
the alternative transcripts whereas all the alternative
transcripts are indicated in the top panel of the
genomic structure. At the protein level, the disease-
associated mutation and SNP sites are highlighted in
the primary structure of the gene products along
with available functional annotation information of
the amino acid residues from the UniProt database
(e.g. enzymatic active sites and post-translational
modification sites, etc.) (Fig. 4B). Information regarding
Figure 4. Screenshots of Mutation@A Glance. An example of visualizing mutation data for STAT3 is shown at the DNA (A) and the protein
levels (B). The nucleotide and amino acid positions of disease-associated mutations and SNPs are coloured magenta and green,
respectively. At the protein level, various types of information for the mutated amino acid residues can be viewed. (C) The detailed
information about the position of nucleotide or amino acid residues selected. (D) A multiple sequence alignment of human and the
other organisms STAT3 protein sequences. (E) Detailed information about the 3D structure displayed with Jmol and the
representation option menu for 3D structure information. (F) External links to other website for various types of information about
the gene, e.g. gene expression and signalling pathway.
No. 3]A. Hijikata et al. 203

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conserved domain from Pfam (http://pfam.sanger.ac.
uk/)51and predicted intrinsically disordered regions
are also displayed. When 3D structure information for
the protein is available, the positions of mutation and
SNP data can be viewed on the monomer or complex
3D structures with the Jmol applet (Fig. 4B). Detailed
information about nucleotide or amino acid residues
of interest is displayed in another window after clicking
on a residue (Fig. 4C). In particular, at the protein level,
an amino acid residue becomes highlighted in the 3D
structure when clicking on it (Fig. 4B). The amino acid
sequence of human can be compared with those of
other organisms by clicking ‘Multiple Alignment’
button(Fig.4D).Therepresentationofthe 3Dstructure
can beselectedfromtwomodeltypes(ribbonorspace-
filling models) and three colouring types (by rainbow,
highlighting mutation positions or residue conserva-
tion) (Fig. 4E). The ‘External Links’ button provides
links to NCBI Entrez Gene (http://www.ncbi.nlm.nih.
gov/sites/entrez?db=gene)52
tion regarding the gene, Human Protein Reference
Database (http://www.hprd.org/)53for information
about the gene product, GeneCards (http://www.
genecards.org/),54the Reference Database of Immune
Cells (http://refdic.rcai.riken.jp/)55for gene expression
profiling data and the KEGG pathway (http://www.
genome.jp/)56
forpathways
(Fig. 4F). By using this visualization facility, mapping
amino acid positions of known ns substitutions on the
crystal structure of the STAT3–DNA complex (PDB
code: 1bg1)57revealed that the disease-associated
missense mutation residue positions were spatially
located at the interface of the homodimer or at the
DNA binding site, whereas the nsSNP residue positions
werelocatedonasurfaceoutsideofthemolecularinter-
action sites (Fig. 5). This suggests that disease-causative
missensemutationsinSTAT3directlyaffecttheprotein–
protein and/or protein–DNA interaction as reported
previously.49,50This is a good demonstration how
Mutation@A Glance could help us interpret mutation
effects at the molecular level.
forgeneralinforma-
involving this gene
3.4.Evaluating the sequence variations in query
sequences
One of the issues of diagnosis of genetic diseases is
how to evaluate the pathogenicity of newly identified
sequencevariations.To
Mutation@A Glance has an interface that allows clini-
cal researchers to assess the impact of an observed
sequence variation in a given DNA sequence for a can-
didate disease-causing gene as the second query form
(Fig. 3B). When a user submits DNA sequences of a
candidate gene in question, this tool returns a list of
sequence variationsfound
sequences at both the DNA and the protein levels
address this issue,
in theinput DNA
(Fig. 6). To identify genetic variations that occur in
input DNA sequences of a given gene, the BLAT
program58is implemented to align the input DNA
sequences with the reference genomic DNA sequence
for the corresponding gene. Figure 6A represents the
alignment status of the query sequence to the refer-
ence sequence. If a sequence variation is found, mul-
tiplelines of detailed
variation, such as the variation types (e.g. substitution,
insertion and deletion), the mutated region (e.g. exon,
intron and 50- or 30-splice sites constituting the GT-AG
rule), the amino acid changes (e.g. missense, non-
sense,insertion/deletion
known variation data (disease-associated mutation
and SNP) and structure/function features of the pos-
ition at the protein level, are displayed based on the
reference human genome sequence in the public
database (Fig. 6B). Sequence alignments between
the query and reference sequences are also displayed
(Fig. 6C). If a ns substitution is found in the query DNA
sequence, it was evaluated by the SIFT program26
(incorporated in the local system), which predicts
whether amino acid substitutions in a protein will
be ‘Deleterious’ or ‘Tolerated’ using evolutionary
information from the homologous proteins (Fig. 6B).
We tested the prediction accuracy of SIFT with
our data sets of disease-associated mutations and
non-disease-associated nsSNPs, and found that the
information about the
andframe-shift),the
Figure5. Spatial localizationof disease-associated missense
mutation sites on the STAT3 protein structure. Two STAT3
subunits are represented as a space-filling model coloured
white (subunit A) and a ribbon model coloured pink (subunit
B), respectively. A double-stranded DNA is represented as a
ribbonmodel coloured light
missense mutations and nsSNPs of STAT3 (subunit A) are
coloured magenta and green, respectively.
green.Thedisease-related
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false-negative rate (falsely predicted as ‘Tolerated’ for
disease-associated mutations) and the false-positive
rate (falsely predicted as ‘Deleterious’ for nsSNPs)
were 25% and 39%, respectively. These accuracy
values were comparable to those evaluated in pre-
vious study.33The current version of Mutation@A
Glance does not implement a method for quantitative
evaluation of mutation effects on RNA splicing, mainly
because we considered the evaluation method is not
matured enough yet. However, because the evalu-
ation of mutation effects on RNA splicing/stability is
very intriguing, we will place a high priority on the
implementation of the evaluation tool for genetic
variations affecting RNA
future development.
There are several advantages of Mutation@A Glance
over other existing web servers for evaluating the
splicing/stability in the
effects of mutations. First, users are only required to
have DNA sequences from a particular gene as their
input and thus do not need to pre-process their sub-
mission data; other websites for evaluating the
mutation effects require a list of genetic variations as
a query, not raw sequence data.26–31Secondly,
Mutation@A Glance identifies and addresses multiple
types of sequence variations (e.g. insertion/deletion,
frame-shifts)frominput
whereas the other web servers do not. Thirdly, newly
identified genetic variations can be easily compared
withknownmutationandSNPdatausingthegraphical
visualization interface of Mutation@A Glance (Fig. 6D).
From a viewpoint of clinical use, it is obvious that any
mutation analysis platform cannot serve as a useful
one without reliable mutation data sets. However,
whereas large amounts of disease-associated mutation
query DNAsequences
Figure 6. An example of evaluating sequence variations in query STAT3 DNA sequences. (A) The mapping status of each query sequence to
the reference sequence is shown. (B) If a variation is found in the query sequence, the detailed information is shown for each variation
(e.g. the positions on the DNA/protein sequences, the type of variation and the description as to whether or not it is known as a disease-
associated mutation or SNP). Results from the SIFT program (‘Tolerated’ or ‘Deleterious’) are also shown if the variation caused ns
substitutions. (C) The query-reference sequence alignment around the altered nucleotides is depicted. (D) The variations can be
visualized in the viewer, represented by different colours for known disease mutations or SNPs as ‘User’s Data’.
No. 3] A. Hijikata et al.205

Page 10

data for various genetic diseases have been reported,
most of them are dispersed and stored locally. Only a
few websites, e.g. OMIM and UniProt, integrate
disease-associated mutation data and allow us to
download their contents. However, the mutation data
in such databases have a relatively low integrity in
terms of updating and coverage. Thus, we have begun
to comprehensively collect and manually curate the
disease-associated mutation data from published lit-
erature focusing on PIDs and established a resource
of PID research for clinical use, named RAPID.17
Mutation@A Glance thus uses these manually curated
data sets for over 150 PID genes in the RAPID database,
which is solid enough for clinical use at least for PID
analysis. To make Mutation@A Glance a reliable and
general mutation analysis platform for other various
genetic diseases in the future, we consider that data
sharing with experts in particular diseases will be
highly important as in the case of PID; otherwise it
would take a long time to accumulate extensive
mutation data of all human disease genes to an accep-
table level for clinical use. In fact, similar efforts along
this direction have been being made by the research
community.19
As new technologies for determining genetic vari-
ation in humans have rapidly and continuously
emerged (such as next generation DNA sequencing),
amounts of genetic variation data of human are expo-
nentially growing.6,7,59Therefore, we will continue to
update and improve the Mutation@A Glance system,
in order to cope with the larger-scale data analysis
for more comprehensive identification of disease-cau-
sative candidate genes. Implementing API programs
into Mutation@A Glance for query submissions and
a retrieval system through command line scripts
would be more convenient for this purpose.
In summary, Mutation@A Glance provides a highly
integrated bioinformatics tool for mutation analysis
not only for facilitating visualization of sequence vari-
ation data along with various types of information,
including primary and tertiary structures of the gene
products, but also for evaluating the effects of novel
sequence variations in a query input DNA sequence.
This tool works solely on a web browser through
Internet and is open to the public. Hence, Mutation@A
Glance can be used as a ‘one-stop’ integrated bioinfor-
matics platform for analysing genotype–phenotype
relationships of genetic diseases from molecular as
well as clinical perspectives.
Acknowledgements:
to thank Drs Shigeaki Nonoyama, Kohsuke Imai,
Hirokazu Kanegane, Toshio Miyawaki, Koichi Oshima,
Fumihiko Ishikawa and Reiko Kikuno-Fukaya for their
critical suggestions about this work.
The authors would like
Supplementary Data: Supplementary Data are
available at www.dnaresearch.oxfordjournals.org.
Funding
This work is supported by a Grant-in-aid for Special
CoordinationFunds for
Technology, from the Ministry of Education, Culture,
Sports, Science and Technology of Japan.
PromotingScience and
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