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Table of Contents: 2012 NOVEMBER–DECEMBER No. 389

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What's New for 2013 MeSH

Schulman J. What's New for 2013 MeSH. NLM Tech Bull. 2012 Nov-Dec;(389):e5.

2012 December 10 [posted]
Other pertinent articles:

MEDLINE/PubMed Year-End Processing Activities

2013 MeSH Now Available

Cataloging News — 2013

MEDLINE Data Changes — 2013

dotWhat's New for 2013 MeSH

Newly Maintained MEDLINE for 2013 MeSH Now Available in PubMed

The 2013 release of the Medical Subject Headings (MeSH) includes improvements in a variety of areas including new ingredient identifiers from the FDA, a redesign of the Carboxylic Acids tree structure and new terms from the disease portion of the Online Mendelian Inheritance in Man (OMIM).

What’s New for 2013 MeSH -- Overview of Vocabulary Development and Changes

  • 302 Descriptors added
  • 26 Descriptor terms replaced with more up-to-date terminology
  • 30 Descriptors deleted

Totals by Type of Terminology

  • 26,853 Descriptors
  • 83 Qualifiers
  • 214,234 Supplementary Concept Records (SCRs)

Helpful Links

Please consult the 2013 online Introduction to MeSH for more details. Lists of new and changed vocabulary are available at these links:

MeSH Vocabulary Changes
New Descriptors - 2013
Changed Descriptors - 2013
Deleted Descriptors - 2013
New Descriptors by Tree Subcategory - 2013

In addition, files of MeSH 2013 vocabulary are also available for downloading.

Unique Ingredient Identifiers (UNIIs) added to MeSH Supplementary Concept Records

US Food and Drug Administration (FDA) Unique Ingredient Identifiers (UNIIs) have been added to a subset of 2013 MeSH SCRs found to match FDA Substance Registration System (SRS) terminology. The UNIIs were inserted into the RN (Registry Number) field of MeSH chemical SCRs and serve as a new system of unique identifiers that will enhance existing Chemical Abstracts Service (CAS) registry numbers and Enzyme Commission (EC) numbers. MeSH terms that matched SRS terminology also received a Thesaurus ID of "FDA SRS (2013)" to indicate the MeSH year of the UNII insertion. In addition, Thesaurus IDs of USAN, USP, or INN sources were added for terms that matched those sources. The UNII insertion process maintained any replaced CAS registry number or EC number to Related Registry number (RR) fields in the MeSH record so that PubMed searches using these numbers will continue to work.

Summary of UNII Insertion Project
UNII identifiers added to RN fields 7,657
FDA SRS terms identified in MeSH 9,317
USAN terms identified in MeSH 584
USP terms identified in MeSH 133
INN terms identified in MeSH 2,523

For additional information see A New System of Registry Number Identifiers for Chemicals in the MeSH Database.

Redesign of the Carboxylic Acids Tree Structure in MeSH

We have simplified the Carboxylic Acids tree structure by consolidating several closely related descriptors. For example, the descriptor Benzoic Acids is deleted in 2013 MeSH and now appears as a subconcept in the descriptor Benzoates. Derivatives of benzoic acid such as Bromobenzoates are listed as descriptors under the common parent Benzoates and include their various salt and ester forms. Pairs of carboxylic acid headings that were consolidated include:

Consolidated Carboxylic Acid Pairs
Acetic Acids Acetates
Aminobenzoic Acids Aminobenzoates
Benzoic Acids Benzoates
Butyric Acids Butyrates
Crotonic Acids Crotonates
Formic Acids Formates
Glucuronic Acids Glucuronates
Hexanoic Acids Caproates
Hydroxybenzoic Acids Hydroxybenzoates
Octanoic Acids Caprylates
Oxalic Acids Oxalates
Oxaloacetic Acids Oxaloacetates
Phosphonic Acids Organophosphonates
Propionic Acids Propionates
Salicylic Acids Salicylates
Succinic Acids Succinates

Online Mendelian Inheritance in Man (OMIM)

MeSH uploaded the disease portion of the Online Mendelian Inheritance in Man (OMIM) database available in the Unified Medical Language System. OMIM is a database that catalogues human diseases with genetic components. Although OMIM disease names are available for searches in PubMed, it is often difficult to index and search for the articles on rare diseases with genetic components because of multiple synonyms used by different scientists that often do not overlap. As was done with NIH Office of Rare Diseases and Research (ORDR) disease terms (see What's New for 2010 MeSH for additional information), OMIM terms were compared to the existing MeSH descriptors and SCR records. When matches were found OMIM thesaurus tags were added to the matched MeSH record terms. Where there were no string matches, new disease SCRs were created and were mapped to descriptor(s) using the Heading Mapped to (HM) field. MeSH created 3,774 new disease SCRs, and identified and tagged 1,498 existing ORDR SCRs as rare diseases with genetic components during the OMIM load. All OMIM disease names therefore will be available starting with MeSH 2013 for indexers and searchers. The use of the HM field in the disease SCRs will lead to more consistent indexing and retrieval for rare genetic diseases.

There were 2,165 terms in 772 descriptors (MeSH headings) matching OMIM terms and therefore, tagged with the Thesaursus ID (TH)=OMIM (2013). An additional 10,286 terms in 5,453 total SCRs (6,331 terms in 3,774 new SCRs and 3,955 terms in 1,498 existing SCRs) were identified during the load. All newly created SCRs were reviewed and mapped to at least one disease descriptor.


Optic Atrophy 7 is a new SCR (C567833) made during OMIM loading and is heading mapped (HM) to Optic Atrophies, Hereditary (D015418) (see Figure 1). Optic atrophy 5, on the other hand, was an existing SCR introduced during ORDR loading, and because OMIM also has the term, an additional Thesaursus ID=OMIM (2013) was added to the SCR record.

Kjer-Type Optic Atrophy is a term in Optic Atrophy, Autosomal Dominant (D029241) and was identified as a disease with genetic components during OMIM load; therefore, an additional Thesaursus ID=OMIM (2013) was added to the term (see Figure 2).

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Figure 1: MeSH Browser record of Optic Atrophy 7, a new SCR with OMIM.

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Figure 2: MeSH Browser screen shot of Kjer-Type Optic Atrophy showing an additional thesaurus added to the term.

By Jacque-Lynne Schulman
MeSH Section

NLM Technical Bulletin National Library of Medicine National Institutes of Health