Clinical_Rounds_in_Endocrinology_Volume_II_-_Pediatric_Endocrinology

315

hCG stimulation test is also useful to differentiate anorchidism from bilateral

cryptorchidism.

Diagnosis Androstenedione Testosterone Dihydrotestosterone Remarks

Androgen

resistance

syndrome

Elevated Elevated Elevated –

5 α-reductase

type 2

defi ciency

Normal to

elevated

Elevated Low T/DHT ratio >10

Androgen

biosynthetic

defects

(17β-HSD3)

Elevated Low Low T: ∆ 4 ratio <0.8

Dysgenetic

testes

Low Low Low No response to

even prolonged

hCG stimulation

test

35. What are the causes of presence of Mullerian derivatives in a child with genital
    ambiguity and palpable gonads?

The presence of Mullerian structures in a child with ambiguous genitalia and

palpable gonads suggests dysgenetic testes or ovotestes. Inability of dysgenetic

testes/ovotestes to produce suffi cient quantity of AMH and testosterone results

in persistence of Mullerian derivates and genital ambiguity, respectively. The

differential diagnosis includes ovotesticular DSD, mixed gonadal dysgenesis,

and 46,XY partial gonadal dysgenesis.

36. How to evaluate a child with genital ambiguity and non - palpable gonads?

Absence of palpable gonads in a child with ambiguous genitalia suggests

either undervirilized 46,XY infant or virilized 46,XX infant. The most com-

mon cause of virilization in 46,XX infant is CAH due to 21α-hydroxylase

defi ciency, and it is important to recognize this disorder as it can be life threat-

ening due to salt-wasting crisis. Undervirilization in 46,XY infant with non-

palpable gonads suggest 46,XY partial gonadal dysgenesis or 17α-hydroxylase

defi ciency. In addition, infants with mixed gonadal dysgenesis and ovotesticu-

lar DSD can also present with genital ambiguity and non-palpable gonads.

Karyotype and stimulated 17(OH)P can establish the diagnosis in a child with

ambiguous genitalia and non-palpable gonads. After establishing the diagno-

sis, gonads should be localized in infants with 46,XY DSD, OT-DSD, and

MGD (Fig. 9.13 ).

9 Disorders of Sex Development