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U.S. National Library of Medicine

Genetics Home Reference provides consumer-friendly information about the effects of genetic variation on human health.

Health Conditions

Learn about the signs and symptoms, causes, and inheritance of more than 1,200 health conditions with a genetic basis.

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Genes

Find information about the function of more than 1,400 genes and see how changes in these genes are related to health conditions.

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Chromosomes & mtDNA

Read about each of the 23 pairs of human chromosomes and mitochondrial DNA (mtDNA).

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Help Me Understand Genetics

Explore topics in human genetics, from the basics of DNA to genomic research and personalized medicine.

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Published: September 10, 2019

The resources on this site should not be used as a substitute for professional medical care or advice. Users with questions about a personal health condition should consult with a qualified healthcare professional.