18 Obstetrics and Gynecology Board Review •••
❍ The loss of the Wolffian system in the female (including the epididymis, vas deferens, and seminal vesicle) is
due to the lack of which hormone?
Testosterone.
❍ Is there any chromosome anomaly that accelerates the process of germ cell loss?
Yes. Turner syndrome (45,X) or gonadal dysgenesis is characterized by a fibrous streak of ovarian tissue that lacks
follicles.
❍ Do individuals with Turner syndrome (45,X) have germ cells, which undergo mitosis and meiosis?
Patients with Turner syndrome have germ cells, which undergo mitosis, but oogonia do not undergo meiosis.
❍ Do individuals with Turner syndrome (45,X) have any follicles at birth?
No.
❍ What are the characteristic findings in someone with Turner syndrome?
The characteristic findings include short stature, streak gonads, webbed neck, high arched palate, cubitus
valgus, shield-like chest with widely spaced nipples, low hairline on the neck, short fourth metacarpal
bones, renal abnormalities, and coarctation of the aorta, primary amenorrhea, lack of secondary sexual
characteristics.
❍ What is Swyer syndrome?
46XY gonadal dysgenesis of the testes caused by a mutation of the SRY gene. They are found to have an XY
karyotype with normal infantile female external genitalia and streak gonads.
❍ Gonadal dysgenesis may also develop in individuals with a mosaic karyotype of 45X/46XX or 45X/46XY.
What tumors must you be concerned about in these patients?
Gonadoblastoma or dysgerminoma.
❍ What are two conditions that cause gonadal dysgenesis but have a normal chromosome complement?
Pure gonadal dysgenesis and gonadal agenesis (male pseudohermaphroditism).
❍ What is the etiology of pure gonadal dysgenesis?
Failure of germ cells to arrive at the gonadal ridge with subsequent failure of ovarian development.
❍ In the bipotential state (6 weeks’ gestation), what does the external genitalia consist of?
Genital tubercle, a urogenital sinus, and two labioscrotal swellings.
❍ External sexual differentiation is under what hormonal influence?
Androgen secretion from the Leydig cells of the testis.
❍ When do the fetal testes begin secreting androgens and when is masculinization complete?
Testes begin secreting androgens at 8 to 9 weeks’ gestation and masculinization is complete by 14 weeks’ gestation.