History and exam
Key diagnostic factors
common
atypical genitalia with no palpable gonads
Although impalpable gonads are more suggestive of a 46,XX disorder of sex development (DSD), an underlying 46,XY DSD is still possible.
atypical genitalia with one palpable gonad
Presence of one gonad makes 46,XX disorder of sex development (DSD) less likely, as ovaries are less likely to descend into the inguinal region. 46,XY DSD, mixed gonadal dysgenesis, and ovotesticular DSD should be considered.
atypical genitalia with bilaterally palpable gonads
Presence of both gonads makes 46,XX disorder of sex development (DSD) less likely and a 46,XY DSD more likely.
penile length <2.5 cm in a phenotypic male
For a term male infant, a normal stretched penile length ranges from 2.0 cm to 2.5 cm.[21] A length of <2.5 cm is considered abnormal in a full-term male baby, especially in the presence of undescended testes or other abnormalities.[21] There is variation in normal penile size between ethnic groups.
In preterm infant males, the penis is shorter and the length should be plotted on a centile chart available for preterm male babies.[25]
clitoris >1 cm in a phenotypic female
A normal clitoral length in a term female infant ranges from 0.2 cm to 0.85 cm, with variation between ethnic groups.[21]
hypospadias and undescended testes or separation of scrotal sacs
Hypospadias is a urethral opening not present at the tip of the phallus.
Presence in combination with separation of scrotal sacs or only one or no palpable gonads suggests a disorder of sex development.
urethral opening at base of phallus
If there are no palpable gonads, the presence of a single urogenital sinus versus a separate vaginal introitus and urethra in a female is more likely to be a 46,XX disorder of sex development (DSD), although a cause of 46,XY DSD is still a possibility.
This occurs when the urethral and vaginal openings exit at the perineum through a common opening.
Other diagnostic factors
common
hypotension and vomiting
Signs of salt wasting (from mineralocorticoid deficiency), including hypotension, weight loss, and vomiting, suggest primary adrenal insufficiency, and congenital adrenal hyperplasia secondary to 21 hydroxylase deficiency is the commonest cause. These infants may have hypoglycaemia from glucocorticoid deficiency.
uncommon
dysmorphic facial features
Presence of dysmorphic features and/or other congenital anomalies suggests a syndromic cause of atypical genitalia. Further hormonal studies may not be necessary if a malformation syndrome is diagnosed.
Risk factors
strong
family history
A family history of consanguinity, genital surgery, infertility, neonatal death, virilisation of a female at puberty (e.g., 5 alpha-reductase deficiency), or other children born with atypical genitalia could suggest a diagnosis.
Most causes of differences of sex development have an autosomal-recessive inheritance, such as congenital adrenal hyperplasia, 5 alpha-reductase deficiency, and defects in testosterone biosynthesis.
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