17 下列那一種疾病所導致的性腺低能症（hypogonadism）的致病機轉與其他三者不同？
(A) Kallmann syndrome
(B) Hypopituitarism
(C) X-linked congenital adrenal hypoplasia
(D) Klinefelter syndrome

Primary v.s. Secondary

(C)X-linked congenital adrenal hypoplasia

Mutations in the NR0B1 gene located on the X chromosome (Xp21.3-p21.2) cause X-linked adrenal hypoplasia congenita. The NR0B1 gene provides instructions to make a transcription factor protein called DAX1 that helps control the activity of certain genes. When the NR0B1 gene is deleted or mutated, the activity of certain genes is not properly controlled. This leads to problems with the development of the adrenal glands, two structures in the brain (the hypothalamus and pituitary gland), and reproductive tissues (the ovaries or testes).