Differences of sexual development and their clinical implications TOG 2020

Question 1

In presence of SRY gene, effect of testosterone on developing foetus

Where is testosterone seceded from

Answer 1

Maintenance of wollfian ducts
Conversion to DHT (5 alpha reductase) forming external genitalia

testosterone = leydig cells

Question 2

In prescence of SRY gene, effect off AMH

Answer 2

Obliteration of Mullerian ducts

Question 3

Effect of no testosterone/DHT/AMH

Answer 3

Obliteration of wollffian ducts, female external genitlia and maintenance of Mullerian ducts

Question 4

What does the Mullerian duct develop into

Answer 4

uterus, cervix, Fallopian tube, upper 2/3 vaginan

Question 5

Turners chromosome

Answer 5

45, XO

Question 6

3 main categories of DSD

Answer 6

Sex chromosome DSD
46, XY DSD
46, XX DSD

Question 7

Kllienfelters chromosome

Answer 7

47XXY

Question 8

Explain complete androgen insensitivity syndrome

Answer 8

Resistant of androgen receptor

Karyoptye XY and tests
Mullerian structures regress (AMH)
Wolfian ducts 50%
Female genitalia

At puberty - breast develop (conversation of testosterone to oestrogen) but scan pubic and axillary hair.

Risk BL inguinal hernia.

Question 9

Difference between luteinising hormone receptor defect and complete androgen insensitivity?

Answer 9

Defect in LH receptor, no production of testosterone.
Similar presentation to CAIS but no breast development

Question 10

How does 5 alpha reductase deficiency present

Answer 10

Female genitlia before developing male genitalia at puberty

XY gene, testes, Mullerian ducts regress (AMH) but no 5-reducrase to convert testosterone to DHT. At puberty other isoenzyme are capable of the conversation

Question 11

Most common deficiency in congenital adrenal hyperplasia?

Answer 11

21 hydroxylase >90% casses

Question 12

How can ‘classical’ CAH present

Answer 12

75% salt wasting crisis (no aldosterone)
Low BP

By comparison 11B-hydroxylase has salt retention and high BP due to accusation of deoxycorticosterone - moderately potent mineralcorticoid

Question 13

How to Ix infant with atypical genitalia or BL impalabe gonads

Answer 13

Thorough Hx and Ex

1. Exclude salt wasting - electrolytes, 17PH progesterone, glucose, urinary steroid profile
2. USS abdo - ?internal genital a
3. Sex chromosomes
4. Establish the presence and function of testes - AMH levels

Question 14

When to Ix primary amenorrhoea

Answer 14

In presence secondary sexual characteristics age 14
Absence of secondary sexual characetistis age 16
5 years since initial onset present development

Question 15

How to Ix adolescent girl with primary amenorrhoea

Answer 15

Hx - weight loss, exercise, stress, chronic disease, Fhc
Ex - height, weight B, signs virilisation

1. Assess electrolytes Na and K
2. Assess hormone levels
   - Estradiol
   - Testosterone
   - Androstenedione
   - Sex hormone binding globulin (SHBG) - Thyroid function tests
   - Prolactin
   - Follicle-stimulating hormone (FSH)
   - LH
3. USS pelvis
4. Establish karyotype