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Fact Sheet
Genetics Home Reference

What is Genetics Home Reference?

Genetics Home Reference is the National Library of Medicine website for consumer information about genetic conditions and the genes or chromosomes associated with those conditions.

Genetics Home Reference is available on the World Wide Web at or through links on MedlinePlus® (

What information is in Genetics Home Reference?

  • Genetic Condition Summaries

Each summary describes the major features of a particular health condition, provides information about the condition's genetic basis, and explains its pattern of inheritance. The summaries also link to support organizations and additional information about the condition.

  • Gene Summaries

Each summary provides the official name and symbol of a gene, its chromosomal location, an explanation of its normal function, and the health implications of variations in the gene. Each gene summary links to more detailed information about the gene.

  • Chromosome Summaries and mitochondrial DNA (mtDNA)

Chromosome summaries provide an estimate of the amount of DNA and number of genes for each chromosome. Each summary also provides information on how changes in the number or structure of the chromosome can lead to certain disorders. A separate summary describes mtDNA and its associated health conditions.

  • Help Me Understand Genetics

This primer on human genetics provides an illustrated, basic explanation of how genes work and how mutations cause disorders. It also includes information about genetic inheritance, gene families, the genetics of normal human traits, genetic testing (including newborn screening), gene therapy, genomics research, and precision medicine.

How are topics selected for Genetics Home Reference?

Genetics Home Reference includes topics that have a known or suspected genetic component. New topics are added regularly. Topics included in complementary resources, such as MedlinePlus, GeneReviews, OMIM, and Genetic Alliance, are more likely to be selected for Genetics Home Reference.

How are Web links selected for Genetics Home Reference?

Genetics Home Reference provides access to information from the National Library of Medicine, the National Institutes of Health, and other U.S. Government agencies.

To complement U.S. Government sources, Genetics Home Reference links to selected nonfederal web sites, consistent with Selection Criteria for Web Links. A link to these selection criteria is available at the bottom of each Web page.

Genetics Home Reference facts

  • Completely confidential; no registration or personal information is required
  • Topics are added and updated on a regular basis and reviewed by experts in human genetics.
  • On the Web since April 2003
  • Redesigned in 2016 with an improved look and feel and better navigation

Need more information?

E-mail address: Contact NLM.

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National Library of Medicine
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Bethesda, Maryland 20894

Phone: (301) 496-6308
Fax: (301) 496-4450