Which of the following is NOT a common single gene disorder?

Cystic fibrosis, while it is indeed a genetic disorder caused by mutations in the CFTR gene, is actually classified as a common single gene disorder. It is characterized by the production of thick and sticky mucus that can clog the lungs and lead to respiratory problems and various other complications.

On the other hand, sickle cell anemia, Tay-Sachs disease, and beta thalassemia are also recognized as single gene disorders. Sickle cell anemia results from a mutation in the HBB gene, Tay-Sachs is caused by a mutation in the HEXA gene, and beta thalassemia involves mutations in the HBB gene as well. Each of these conditions stems from alterations in a specific gene, leading to distinct clinical manifestations.

Understanding that cystic fibrosis is a common single gene disorder clarifies why it does not fit the criteria of the question asking for a disorder that is NOT common among this category.