In Tunisia, Charfeddine et al. [57] determined the genetic defect CYP21A2 in 50 Tunisian patients with the clinical diagnosis of 21-hydroxylase deficiency, with CYP21A2 mutations being identified in 87% of the alleles, whereas the most common point mutation was the pseudogene specific variant p.Q318X (26%). Here, CYP21A2 is linked to classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency.