As mentioned above, one of the hallmarks of HB at the molecular level is damage to the CTNNB1 gene encoding β-catenin in the third exon in the form of deletions or insertions [51], but most often, the loss of serine/threonine residues (in codons S33, S37, S45 and T41), as well as the substitution of tyrosine for alanine (T41A) [52]. This evidence concerns the gene CTNNB1 and hemoglobin measurement.