Mehl. Klinefelter syndrome + Swyer syndrome 04-15 (1)

Question 1

Mehl. karyotype?

Answer 1

47XXY karyotype; male phenotype.

Question 2

Mehl. stature, shape?

Answer 2

Tall, eunuchoid body shape

Question 3

Mehl. what testes?

Answer 3

mall testes

Question 4

Mehl. neuro?

Answer 4

reduced IQ.

Question 5

Mehl. breasts?

Answer 5

gynecomastia

Question 6

Mehl. Q might say there is presence of electron-dense mass in the cell on electron microscopy, what is it?

Answer 6

i.e., a Barr body

Question 7

Mehl. what about seminiferous tubules?

Answer 7

Testes are present but are small; there is dysgenesis of the seminiferous tubules.

Question 8

Mehl. LH and FSH levels?

Answer 8

leading to incr.­ LH and FSH due to decr. negative-feedback from decr. androgens and inhibin.

Question 9

Mehl. Estrogen/androgen ratio is …..? why?

Answer 9

­Incr. due to dysgenesis of Leydig cells (which make androgen).

Absolute estrogen is also ­incr. due to ­incr. adipose tissue (therefore ­ aromatase).

Question 10

Mehl. risk for what cancer?

Answer 10

Incr. risk of breast cancer; risk of testicular cancer is only very subtly incr., so prophylactic orchiectomy is not indicated.

Question 11

Mehl. should we do prophylactic orchiectomy?

Answer 11

risk of testicular cancer is only very subtly incr., so prophylactic orchiectomy is not indicated.

Question 12

Mehl. Swyer syndrome. chromosomes?

Answer 12

46XY; phenotypically female.

Question 13

Mehl. Swyer syndrome. caused by what?

Answer 13

Caused by failure of the primitive gonads to develop into testes, but they don’t develop into ovaries either. They develop into streak gonads.

Question 14

Mehl. Swyer syndrome. what causes to manifest female phenotype?

Answer 14

decr. androgen production causes external female phenotype. Also leads to scanty/absent pubic/axillary hair.

Question 15

Mehl. Swyer syndrome. Absence of MIF lead to what?

Answer 15

Absence of MIF (since no testes) means Müllerian structures develop.

Question 16

Mehl. Swyer syndrome. CP?

Answer 16

Presents similar to AIS – i.e., phenotypic female with scanty/absent pubic/axillary hair, BUT there are Müllerian structures (i.e., uterus, Fallopian tubes, cervix, and upper vagina) and decr. androgens, whereas in AIS, Müllerian structures are absent and androgens are normal or incr. (tissues are just insensitive to them).

Question 17

Mehl. MIF deficiency = Müllerian-inhibitory factor deficiency.

Answer 17

.

Question 18

Mehl. MIF deficiency. karyotype?

Answer 18

46XY karyotype;

Question 19

Mehl. MIF deficiency. phenotype?

Answer 19

phenotypically male with testes (i.e., internal and external structures are male), but failure of regression of the Müllerian ducts means a uterus, Fallopian tubes, cervix, and upper vagina are present.

Question 20

Mehl. MIF deficiency.

he Müllerian structures are usually located in the pelvis between the bladder and rectum (similar to location for uterus in a female), or in the inguinal canal.

Answer 20

They are often discovered incidentally during orchidopexy for cryptorchidism.

Question 21

Mehl. MIF deficiency.

In other words, the Q can say there are undescended testes, where upon surgical reduction into the scrotum, a primitive uterus and Fallopian tubes are discovered.

Answer 21

.

Question 22

UW. Dx of Klinefelter?

Answer 22

Karyotype analysis is used to diagnose Klinefelter syndrome (47,XXY)

Question 23

UW. common cause gynecomastia?

Answer 23

Klinefelter syndrome (47,XXY)