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Biomedical subjects

Jouni Väliaho

Publications and source records attributed to Jouni Väliaho.

7 recordsLinked to original sources

Immunodeficiency mutation databases (IDbases).

Primary immunodeficiencies (IDs) are a heterogenic group of inherited disorders of the immune system. Immunodeficiency patients have increased susceptibility to recurrent and persistent, even life-threatening infections. Mutations in a large number of genes can cause defects in different cellular functions and lead to impaired immune response. To date, approximately 150 IDs and more than 100 affected genes have been identified. ID-related genes are distributed throughout the genome, and diseases can be inherited in an X-linked, an autosomal recessive, or an autosomal dominant way. We have collected ID mutation data into locus-specific patient-related mutation databases, IDbases (http://bioinf.uta.fi/IDbases). Mutations are described at DNA, mRNA, and protein levels with links to reference sequences and reference articles. The mutation data has been collated into entries along with some clinical information. IDbases offer an easy way, e.g., to find recently identified mutations, to reveal genotype-phenotype correlations, and to discover a specific mutation or to examine the most common mutations in a single immunodeficiency related gene. At the moment we have databases for 107 ID genes with 4,140 public patient entries. An exhaustive statistical analysis of mutation data from the IDbases was made. Missense and nonsense mutations are the most common mutation types, and the most common single substitution is a nonsense mutation from tryptophan to a stop codon. Arginine is the most mutated as well as the most abundant mutant amino acid.

Amino Acid Sequence↗

BTKbase: the mutation database for X-linked agammaglobulinemia.

X-linked agammaglobulinemia (XLA) is a hereditary immunodeficiency caused by mutations in the gene encoding Bruton tyrosine kinase (BTK). XLA patients have a decreased number of mature B cells and a lack of all immunoglobulin isotypes, resulting in susceptibility to severe bacterial infections. XLA-causing mutations are collected in a mutation database (BTKbase), which is available at http://bioinf.uta.fi/BTKbase. For each patient the following information is given (when available): the identification of the entry, a plain English description of the mutation followed by a reference, formal characterization of the mutation, and the various parameters from the patient. BTKbase is implemented with the MUTbase program suite, which provides an easy, interactive, and quality controlled submission of information to mutation databases. BTKbase version 8 lists mutation entries of 1,111 patients from 973 unrelated families showing 602 unique molecular events. The localization of the mutations on the gene and protein for BTK can be analyzed by clicking sequences on the web pages. The distribution of the mutations in the five structural domains is approximately proportional to the length of the domains, except for the Tec homology (TH) domain. The most frequently affected sites are CpG dinucleotides. The majority of the missense mutations are structural-disturbing Bruton tyrosine kinase (Btk) folding or decreasing stability. Many of the mutations affect functionally significant, conserved residues. The structural consequences of the mutations in all the domains have been studied based on crystallographic and nuclear magnetic resonance (NMR) structures as well as computer-aided molecular modeling.

Agammaglobulinemia↗

Distribution of immunodeficiency fact files with XML--from Web to WAP.

BACKGROUND: Although biomedical information is growing rapidly, it is difficult to find and retrieve validated data especially for rare hereditary diseases. There is an increased need for services capable of integrating and validating information as well as proving it in a logically organized structure. A XML-based language enables creation of open source databases for storage, maintenance and delivery for different platforms. METHODS: Here we present a new data model called fact file and an XML-based specification Inherited Disease Markup Language (IDML), that were developed to facilitate disease information integration, storage and exchange. The data model was applied to primary immunodeficiencies, but it can be used for any hereditary disease. Fact files integrate biomedical, genetic and clinical information related to hereditary diseases. RESULTS: IDML and fact files were used to build a comprehensive Web and WAP accessible knowledge base ImmunoDeficiency Resource (IDR) available at http://bioinf.uta.fi/idr/. A fact file is a user oriented user interface, which serves as a starting point to explore information on hereditary diseases. CONCLUSION: The IDML enables the seamless integration and presentation of genetic and disease information resources in the Internet. IDML can be used to build information services for all kinds of inherited diseases. The open source specification and related programs are available at http://bioinf.uta.fi/idml/.

Database Management Systems↗

KinMutBase: a registry of disease-causing mutations in protein kinase domains.

A large number of disease-causing mutations have been identified from several protein kinases. KinMutBase is a comprehensive knowledge base for human disease-related mutations in protein kinase domains (http://bioinf.uta.fi/KinMutBase/). The latest version contains 582 different mutations for 1,790 cases in 1,322 families. KinMutBase entries are described on the DNA, mRNA, and protein level. Numbers for affected patients and families are also provided. KinMutBase has extensive amount of links and cross-references to literature, other databases, and information sources. There are numerous interactive pages about sequences, structures, mutation statistics, and diseases. Detailed statistical study was done on frequencies of different types of mutations both on the DNA and protein level in serine/threonine kinase (PSK) and tyrosine kinase (PTK). Three-dimensional structures indicate clustering of disease-related mutations mainly to conserved subdomains, and substrate and coligand binding amino acids, although mutations appear throughout the sequences. CpG containing codons, especially for arginine, constitute the majority of mutational hotspots. There are certain clear differences in mutation patterns and types between PSKs and PTKs.

Amino Acid Sequence↗

Bruton's tyrosine kinase: cell biology, sequence conservation, mutation spectrum, siRNA modifications, and expression profiling.

Bruton's tyrosine kinase (Btk) is encoded by the gene that when mutated causes the primary immunodeficiency disease X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency (Xid) in mice. Btk is a member of the Tec family of protein tyrosine kinases (PTKs) and plays a vital, but diverse, modulatory role in many cellular processes. Mutations affecting Btk block B-lymphocyte development. Btk is conserved among species, and in this review, we present the sequence of the full-length rat Btk and find it to be analogous to the mouse Btk sequence. We have also analyzed the wealth of information compiled in the mutation database for XLA (BTKbase), representing 554 unique molecular events in 823 families and demonstrate that only selected amino acids are sensitive to replacement (P < 0.001). Although genotype-phenotype correlations have not been established in XLA, based on these findings, we hypothesize that this relationship indeed exists. Using short interfering-RNA technology, we have previously generated active constructs downregulating Btk expression. However, application of recently established guidelines to enhance or decrease the activity was not successful, demonstrating the importance of the primary sequence. We also review the outcome of expression profiling, comparing B lymphocytes from XLA-, Xid-, and Btk-knockout (KO) donors to healthy controls. Finally, in spite of a few genes differing in expression between Xid- and Btk-KO mice, in vivo competition between cells expressing either mutation shows that there is no selective survival advantage of cells carrying one genetic defect over the other. We conclusively demonstrate that for the R28C-missense mutant (Xid), there is no biologically relevant residual activity or any dominant negative effect versus other proteins.

Agammaglobulinaemia Tyrosine Kinase↗

Online registry of genetic and clinical immunodeficiency diagnostic laboratories, IDdiagnostics.

Primary immunodeficiencies (IDs) are caused by inherited genetic defects leading to intrinsic defects in cells of the immune systems. Most IDs are rare diseases and can be difficult to diagnose because similar symptoms characterize several disorders. Mutation detection is the most reliable method in such cases. These tests are not available at most centers and physicians can have difficulties in finding laboratories that could analyze the genetic defects because certain genes are possibly analyzed by just one laboratory. The IDdiagnostics registry has been established to provide information for physicians and other health care professionals. The database at http://bioinf.uta.fi/IDdiagnostics contains currently information for the analysis of defects in 30 ID-related genes. Another part of IDdiagnostics is a database of clinical tests. Laboratories performing these analyses, either gene or clinical tests, are asked to submit their information to the database by using a printed form or electronic submission at http://bioinf.uta.fi/cgi-bin/submit/IDClini.cgi. The clinical test database contains information about tests for clinical data, immune status, and studies of function, antibody response, cell function, enzyme assays, clinical function, and apoptosis assays. Both the services are freely available and regularly updated. The services aim at increasing the awareness of IDs and helping to obtain exact and early diagnosis.

Databases as Topic↗

IDR: the ImmunoDeficiency Resource.

The ImmunoDeficiency Resource (IDR), freely available at http://www.uta.fi/imt/bioinfo/idr/, is a comprehensive knowledge base on immunodeficiencies. It is designed for different user groups such as researchers, physicians and nurses as well as patients and their families and the general public. Information on immunodeficiencies is stored as fact files, which are disease- and gene-based information resources. We have developed an inherited disease markup language (IDML) data model, which is designed for storing disease- and gene-specific data in extensible markup language (XML) format. The fact files written by the IDML can be used to present data in different contexts and platforms. All the information in the IDR is validated by expert curators.

Database Management Systems↗