313establish the etiological diagnosis. Age-specifi c cutoffs for serum testosterone
and AMH are to be used for interpretation of the results. Estimation of serum
LH is helpful during minipuberty and after the onset of puberty; however, it has
limited utility during “window period.” The diagnostic workup of a child with
ambiguous genitalia and palpable gonads is shown in the fi gure given below
(Fig. 9.11 ).- A 2 - year - old child was brought with history of genital ambiguity since birth.
The clinical profi le of the patient is depicted below. What are the differential
diagnoses in the index case?
This child was reared as a boy and was brought for evaluation of genital ambi-
guity at the age of 2 years. Examination of genitalia revealed bifi d scrotum with
rugosity, bilateral scrotal testes (size 2 ml each), phallus with chordee, ventral
urethral groove, and perineoscrotal hypospadias. The external masculinization
score was 6. Since both the gonads are palpable, a clinical diagnosis of 46,XY
DSD was considered. The differential diagnosis in this child includes androgen
biosynthetic defects (ABSD), partial androgen insensitivity (PAIS), and
5 α-reductase type 2 defi ciency. Rarely, CAH due to 3β-HSD2 and POR defi -
ciency can be associated with 46,XY DSD (Fig. 9.12 ).Ambiguous genitalia with palpable gonad/s46XX 46,XX/46,XY 45X/46XY 46 XYMGD TestosteronehCG stimulation test
AMHNormal/↑TestosteroneBasal LH & hCG stimulation testT/DHT ratio >105 α′-Reductase
Deficiency type 2PAIS*A= Androstenedione
**T= TestosteroneT:A ratio <0.8 ↑ basal LH
normal AMH↓A, ↓T
normal AMH↓A*, ↓T**
↓AMH46XY partial GD 17 β-HSD3
deficiency- LH receptor mutation
- StAR deficiency
- CYP11A1 deficiency
- CYP17A1 deficiency
- 3β-HSD deficiency
- POR deficiency
OT-DSD↓TestosteroneOT-DSD
Testicular DSDFig. 9.11 Approach to a child with ambiguous genitalia and palpable gonads
9 Disorders of Sex Development