Databases and Systems

The Entry
Each OMIM entry is assigned a unique number. Entries are prepared for each
distinct gene or genetic disorder for which sufficient information exists and are not
made for genes known only from expressed sequence tags (ESTs), pseudogenes,
genetic markers (e.g., “D” segments), or even complete cDNAs for which nothing is
known other than the sequence. Many disorders that are not yet characterized at the
level of the gene or even at any meaningful biochemical level are included as entries
if they show Mendelian inheritance. A major goal of OMIM is to help with the
discovery process whereby a gene sequence and a mapped phenotype can be
associated. When this occurs the separate entries may be merged.
OMIM authors do not wittingly create more than one entry for each gene locus.
The kinds of information that may be included in entries are the approved gene name
and symbol (obtained from the HUGO Nomenclature Committee), alternative names
and symbols in common use, information about the map location in man and mouse,
how it was cloned, information about the protein and DNA sequence such as the size
of the gene, the type of product made, what its known or inferred function might be,
where the gene is expressed, whether it is related to other similar genes in man or
other species and whether there are animal models. For entries where the gene
causes a disease, information about key allelic variants is included and clinical details
are presented.
Care is taken to assure that distinctive characteristics of given clinical disorders
are noted, including variations from the usual case. The information is intended as a
guide in diagnosis and management of the particular disorder. Clinical information,
given in succinct form, is supplemented by that provided in carefully selected
citations that accompany each entry.
Text entries are generally diachronic, meaning that they are added to in
chronological order, with the most recent material at the end. This is done, in part, to
minimize the effort of having to rewrite thousands of entries each time they are
amended and to reflect the historical progression of the knowledge about the locus.
Many of the larger entries, for which there is a wealth of information, have been
restructured into topical sections. These topics comprise the Table of Contents (see
Fig. 2) at the top of the entry. For these entries, new information is added in
chronological order into the appropriate section.
User Comments
OMIM encourages users to offer comments about existing entries and suggestions for
improvements or additions of materials. Comments relating to scientific and editorial
content are forwarded by NCBI to the editorial staff at Johns Hopkins.
Clinical Synopses
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