DSD clinical evaluation

Question 1

When to suspect DSD clinically, for males and females?

Answer 1

Any discordance between genotype and phenotype

Male:

1) bilateral cryptorchidism
2) severe hypospadias (scrotal / perineal urethra)
3) hypospadias + undescended testicle
4) Hypospadias + micropenis (<2.5 cm streched)

Female:

1) clitoromegaly (> 6mm width or >9mm lenght)
2) Posterior labial fusion (due to androgen action - may use anogenital ratio)
3) Gonads palpable in labioscrotal fold / inguinal region

Question 2

Name 1 laboratory test and 1 finding on physical exam compatible with congenital adrenal hyperplasia

Answer 2

test: 17-hydroxyprogesterone (a metabolite which is elevated in 21-hydroxylase deficiency. it is used as an indirect measurement 21-hydroxylase deficiency)

finding on exam: virilization of female genitalia

Bonus: concomitant daily measurement of serum electrolytes can identify salt-wasting CAH (hyponatremia and hyperkalemia)

Question 3

What are the 3 most common causes of DSD (all gender combined)?

Answer 3

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency in an XX individual
Sex chromosome mosaicism (XX/XY)
Androgen insensitivity syndrom in an XY individual