allelic heterogeneity

genetics

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July 16, 2026

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Allelic heterogeneity refers to a situation in genetics where different mutations within the same gene can cause the same or similar genetic disorders. This means that even though the gene is the same, variations in its sequence (alleles) can lead to different manifestations of a disease.1

In genetics, an allele is a variant form of a gene. Genes reside at specific locations on chromosomes, and individuals inherit two copies of each gene, one from each parent. If these copies differ, they are called alleles. While a single gene can have multiple alleles, only two are present in an individual at any given gene locus. Allelic heterogeneity highlights that multiple different alleles can affect the same gene, leading to a particular trait or disease. This contrasts with allelic homogeneity, where a specific disease is consistently caused by the same mutation.231

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human genetic disease
Autosomal dominant inheritance
…in the affected population (allelic heterogeneity). In some cases even mutations in different genes can lead to the same clinical disorder (genetic heterogeneity). Achondroplasia is characterized by allelic homogeneity, such that essentially all affected individuals carry exactly the same mutation.
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…in the affected population (allelic heterogeneity). In some cases even mutations in different genes can lead to the same clinical disorder (genetic heterogeneity). Achondroplasia is characterized by allelic homogeneity, such that essentially all affected individuals carry exactly the same mutation.
Read More