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31. How to approach a neonate with genital ambiguity?

The fi rst step in the evaluation of a neonate with genital ambiguity is a meticu-

lous clinical examination for the presence or absence of gonad/s. Palpable

gonad/s in a child with ambiguous genitalia suggests the presence of testes or

ovotestis; as testes descend, ovaries do not and ovotestes/dysgenetic testes par-

tially descend. Absence of palpable gonad/s in a child with ambiguous genitalia

suggests either undervirilized 46,XY infant or virilized 46,XX infant. The

external genitalia in undervirilized 46,XY infant and virilized 46,XX infant is

usually symmetrical; however, asymmetrical external genitalia suggests the

diagnosis of mixed gonadal dysgenesis (MGD) or ovotesticular DSD (OT-DSD).

An approach to genital ambiguity in a newborn based on clinical examination

and estimation of serum 17(OH)P is given in the fi gure below (Fig. 9.10 ).

32. How to evaluate a child with genital ambiguity and palpable gonads?

In a child with genital ambiguity and palpable gonads, karyotyping, serum tes-

tosterone, anti-Mullerian hormone (AMH), and hCG stimulation test help to

Infant with ambiguous genitalia

Are the gonad/s palpable?

Yes No

Asymmetry of gonads or external genitalia? ACTH-simulated 17OHP

Yes

• OT-DSD


• MGD
  
  
  • CAH-21α-
    hydroxylase
    deficiency
  
  
  
  

Elevated Normal

• OT-DSD


• MGD


• 46, XY partial gonadal
  dysgenesis


• Exogenous androgen


• Placental aromatase
  deficiency


• PAIS


• Androgen biosynthetic defect


• 5 α′-reductase deficiency


• 46 XY partial gonadal
  dysgenesis


• 3β-HSD deficiency

No

Fig. 9.10 Approach to a newborn with ambiguous genitalia

9 Disorders of Sex Development