Essential Genes and Human Genetic Disease


Essential genes are those genes required for an organism to complete development and survive to birth. There is debate as to whether essential genes play a role in human disease, because if they are critical for survival then mutations in these genes will cause lethality during development, removing individuals carrying these mutations from the population. Yet, essential genes can have diverse mutations that either limit or alter their function in a manner that allows individuals with these mutations to survive. These nonlethal, yet pathological, mutations in essential genes do contribute to human disease. Studies have demonstrated that essential disease genes are highly conserved, participate in many protein–protein interactions and may cause both Mendelian and complex disorders. These results confirm that essential genes are valid candidates as disease loci.

Key Concepts:

  • Genetic mutations create different alleles of genes.

  • Hypomorphic alleles retain some gene function.

  • Essential genes are those that are absolutely required for the survival of the organism, and have null alleles with lethal phenotypes.

  • Human disease can be caused by hypomorphic mutations in essential genes.

  • Essential genes do contribute to human nondevelopmental diseases.

  • Essential genes can contribute to Mendelian disease and complex disorders.

Keywords: essential genes; disease; genetics; lethality; mutation; development

Figure 1.

Different allele types generated by genetic mutations. The protein encoded by the wild type gene is shown on the left. The protein encoded following a null mutation is shown in the middle; note that there is no functional protein present. The protein encoded by a hypomorphic mutant allele is shown on the right. Protein activity is diminished but not completely eliminated.



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Further Reading

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Hentges, Kathryn E(Sep 2013) Essential Genes and Human Genetic Disease. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0025172]