AR and partial androgen insensitivity syndrome: The mainstay of the diagnosis of PAIS is the presence of a 46 XY karyotype, the determination of the normality (baseline or after hCG stimulation) of testosterone and dihydrotestosterone levels (in order to exclude defects in testosterone biosynthesis or 5α-reductase 2 deficiency), and the confirmation of the diagnosis through the identification of a molecular defect in AR gene.