Describe the prevalence.
Approx. 1:650 population in the US [8]
One of the most common causes of male hypogonadism
Describe the etiology.
Usually due to nondisjunction of sex chromosomes during meiosis
Associated with advanced maternal age
Describe the karyotype.
47,XXY (rarely 48,XXXY or 48,XXYY)
Presence of a Barr body (inactivated X chromosome)
Describe the pathophysiology.
Testicular dysgenesis leads to:
Seminiferous tubules dysgenesis → loss of Sertoli cells → ↓ inhibin B → ↑ FSH
Leydig cell dysfunction → ↓ testosterone → ↑ LH
Both ↑ LH and ↑ FSH lead to increased conversion of testosterone to estrogen.
Last changeda year ago