<unk>  is likely multifactorial, and is characterized by severely reduced or absent spermatogenesis despite the presence of both<unk>  and Leydig<unk> s. A substantial subset of men with this uncommon syndrome have microdeletions in the Yq11 region of the Y chromosome, an area known as the AZF (azoospermia factor) region. In particular,<unk>  (SCO) correlates with AZFa microdeletions. It is possible to recognize two types of SCO: SCO type 1 shows total absence of spermatogonia because of an altered migration of primordial germ<unk> s from yolk sac to gonadal ridges; SCO type 2 is instead due to a subsequent damage and shows the presence of rare spermatogonia in a minority of tubules. Generally, testosterone and LH levels are normal, but due to lack of inhibin, FSH levels are increased.
Sertoli cell-only syndrome
Persistent adrenarche syndrome
Angelman syndrome
Perlman syndrome
Klinefelter syndrome
Familial male-limited precocious puberty
Young's syndrome
Partial androgen insensitivity syndrome