What does allelic heterogeneity refer to?

Allelic heterogeneity refers to the phenomenon where different variants of a single gene can lead to the same disorder. This concept is significant in genetic counseling and clinical genetics, as it helps explain why individuals with the same genetic condition may have different mutations in the same gene and yet present with similar clinical features. For example, in conditions like cystic fibrosis or sickle cell disease, various mutations in the CFTR gene or the HBB gene respectively can result in the same disorder. Understanding allelic heterogeneity is crucial for accurate diagnosis, genetic testing, and the development of tailored treatment approaches. This distinction allows healthcare professionals to appreciate the complexity of genetic conditions that arise from mutations in a single gene rather than multiple genes.