Disorders of sex hormones

Question 1

What is androgen insensitivity syndrome?

Answer 1

• X-linked recessive condition
• Defect in androgen receptor => end-organ resistance to testosterone
• 46XY genotype but female phenotype
• vagina and testes present but no uterus
• Testosterone, oestrogen and LH levels are elevated

Question 2

What is 5-α reductase deficiency?

Answer 2

• Autosomal recessive condition. - males cant convert testosterone to dihydrotestosterone (DHT)

=> ambiguous genitalia in the newborn period
- Hypospadias common.
- Virilisation at puberty

Question 3

Describe the amount of LH and testosterone in the following disorders:
A) Klinefelters
B) Kallmans
C) Androgen Insensitivity
D) Testosterone secreting tumour

Answer 3

A) High LH, Low Testosterone

B) Low LH and testosterone

C) High LH, normal-high testosterone

D) Low LH, High testosterone

Question 4

What is the karyotype in Klinefelters?

Answer 4

47XXY

Question 5

Features in Klinefelters

Answer 5

• taller than average
• lack of secondary sexual characteristics
• small, firm testes
• infertile
• gynaecomastia
• elevated gonadotrophin levels

Question 6

How is kallmans syndrome inherited?

Answer 6

X-linked recessive

Question 7

Features in kallmans syndrome

Answer 7

• ‘delayed puberty’
• cryptorchidism
• ANOSMIA
• LH, FSH levels LOW
• normal or above average height
• Cleft lip/palate and visual/hearing defects in some

Question 8

Presumed pathophysiology of kallmans

Answer 8

Failure of GnRH secreting neurons to migrate to hypothalamus

Question 9

Features of androgen insensitivity syndrome

Answer 9

• primary amenorrhoea
• undescended testes causing groin swellings

Question 10

How is androgen insensitivity syndrome managed?

Answer 10

• bilateral orchidectomy (increased risk of testicular cancer in undescended testes)
• oestrogen therapy