Use case diagram describing possible data exploration while diagnosing diabetes mellitus based on the sequence of the HNF1A gene. Genetics lab worker obtains the nucleotide sequence of the HNF1A (hepatocyte nuclear factor HNF-1alpha) gene in the laboratory. He/she performs the sequence analysis, which may include the comparison of the obtained gene sequence to the reference sequences from the GenBank. The sequence comparison can be done by any program, e.g. Sequence Navigator, and must be preceded by a referential sequence search, which can be done using search GenBank. If there are no DNA changes in the patient’s sequence the lab worker reports no changes. Otherwise, he/she verifies whether there are any entries in the SNP database reporting the change in such position of the gene sequence and whether the change has been described and is pathogenic (polymorphic site or mutant). In case of mutants, he/she can analyze mutant sequences by exploring records from the GenBank, related protein sequences from the Protein database and related protein 3D structures from the MMDB. At any moment, he/she may want to broaden his/her knowledge about the change by finding and reading publications from the PubMed database.