CTNNB1 and hemoglobin measurement: Attesting to the notion that considerable genetic drift has occurred is the fact that independent studies have described different sizes of in-frame deletions involving exons 3 and 4 of the CTNNB1 gene that encodes β-catenin (or CTNNB1), the major oncogenic driver of HB [10,36,37,38,52,53,54,55,56].