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MedlinePlus Genetics Data Files & API

MedlinePlus Genetics provides programmatic retrieval of selected data via API. (For other data available from MedlinePlus, please see MedlinePlus XML Files and MedlinePlus Web Service.)

Genetics Page Index

Titles, URLs, and synonyms for Help Me Understand Genetics pages, and genetic condition, gene, chromosome, and mtDNA pages with summaries written for consumers, are available in XML at

Genetic Condition & Gene Details

Information from individual genetic condition, gene, chromosome, and mtDNA pages is available in XML and JSON. The data are best interpreted using the labeling and context of their corresponding pages on the website.

To access a MedlinePlus Genetics page via API, replace the page URL with the corresponding API data URL using the following pattern:

Additionally, a compendium of all XML instances is available in one XML file:

We are no longer providing API data in JSONP format.

Notes on Certain Fields:

  • A genetic condition may have multiple possible inheritance patterns. For example, the combination of "ad" and "ar" means the condition has an autosomal dominant inheritance pattern in some cases and an autosomal recessive pattern in some other cases.
  • The "db-key-list" relates the MedlinePlus Genetics topic to other databases. The db-key entries are meant only as pointers, and the linked resource or concept might not strictly match the scope of the MedlinePlus Genetics page. In particular, the SNOMED CT and ICD-10-CM links were chosen to support MedlinePlus Connect and might not be broadly applicable.
  • The "related-health-condition-list" on gene and chromosome pages reflects genetic condition pages that refer to the gene or chromosome.

Descriptive text from MedlinePlus Genetics is included when available.

Search Results

Base URL


Required Parameters for Initial Search Request

Required Parameters for Initial Search Request
Parameter Name Description
db Database to search. It is "ghr" for MedlinePlus genetics content.
term Text query submitted to the Web service. All special characters must be URL encoded. Spaces may be replaced by '+' signs, which represent the AND operator. Represent the OR operator as +OR+. To send a query as a phrase, enclose the phrase in quotes using %22 to represent quotation marks.


Required Parameters for Subsequent Requests

Required Parameters for Subsequent Requests
Parameter Name Description
file Name of the file containing the document references for the current search. This parameter is required when retstart is being used. The value is obtained from the XML returned from the initial search. The file will expire after a certain period of inactivity, after which a new request must be initiated. If the file is expired, the XML output will contain an error message.
server Name of the server with the file referenced by the file parameter. This is required when the file parameter is being used.
retstart Sequential index of the first document in the retrieved set to be shown in the XML output (default=0, corresponding to the first record of the entire set). This parameter can be used in conjunction with retmax to download an arbitrary subset of documents retrieved from a search.

To see subsequent results, use the <file> and <server> values returned in the initial search request XML, and specify which set of results you would like returned. The subsequent request URL would be constructed like this:{$file}&server={$server}&retstart={$startFrom}

Optional Parameters

Optional Parameters
Parameter Name Description
retmax Total number of documents from the retrieved set to be shown in the XML output (default=10). By default, the web service only includes the first 10 documents retrieved in the XML output. Increasing retmax allows more of the retrieved documents to be included in the XML output.
tool A string with no internal spaces that identifies the resource which is using the Web service (e.g., tool=myservicename). This argument is used to help NLM provide better service to third parties using the Web service from programs. As with any query system, it is sometimes possible to ask the same question different ways, with different effects on performance. NLM requests that developers sending a large volume of requests include a constant 'tool' argument for all requests using the Web service.
email Email address. If you choose to provide an email address, NLM may use it to contact you if there are problems with your queries. In addition to using the email address parameter, we encourage all Web service users to sign up for the email list referenced at the top of this page to receive general announcements and notifications of changes to the service.

Examples (retmax):