A patient, who appears to be female, is found to be 46, XY. The patient's vagina is very shallow, ending in a blind pouch, and there are palpable masses in the labia. The diagnosis of testicular feminization syndrome is made. Which of the following was most likely present during the early fetal life of this individual?
a. A streak ovary
b. A uterus
c. Depressed levels of testosterone
d. MIF (Mullerian inhibitory factor)
The Correct option is D
Explanation with High Yield Facts:
Testicular feminization is a disorder of the androgen receptor. Phenotypically, the patient appears female, but has a blindly ending vagina and lacks a uterus or other female internal reproductive organs. The patient has an XY genotype. Since the gene for testes determining factor (TDF) is on the Y chromosome, TDF will cause the indifferent gonad to develop into a testis containing Sertoli cells. Sertoli cells at this stage will secrete MIF, a substance that suppresses the paramesonephric ducts, preventing the formation of female internal reproductive organs. This patient would not have a streak ovary, a finding in Turner's syndrome that is associated with a 45, XO genotype. In fact, the patient would have testes, since the genetic complement contained a Y chromosome. The testes in individuals with testicular feminization syndrome are often undescended and are usually removed surgically. This patient would not possess a uterus. Both of these structures are derived from the paramesonephric duct, which is suppressed by MIF. Depressed levels of testosterone would not occur in this patient. In fact, individuals with testicular feminization syndrome have normal or even slightly elevated levels of testosterone. The development of female external genitalia is the result of defective androgen receptors, not depressed levels of testosterone.
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