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Difficulty: MediumReproductive Endocrinology and Infertility

A reproductive endocrinology clinic is evaluating four adolescent patients who each present with primary amenorrhea. Based on the findings from physical examinations, laboratory testing, and karyotype analysis, match each patient's clinical profile with the most likely diagnosis.

  • Absent uterus, normal breast development, present axillary and pubic hair, 46,XX karyotype, normal female-range testosterone.Müllerian agenesis (Mayer-Rokitansky-Küster-Hauser syndrome)
  • Absent uterus, normal breast development, scant or absent axillary and pubic hair, 46,XY karyotype, male-range testosterone.Complete androgen insensitivity syndrome
  • Present uterus, absent breast development, low FSH and LH levels, normal karyotype, anosmia.Kallmann syndrome
  • Present uterus, absent breast development, highly elevated FSH and LH levels, 45,X karyotype, short stature.Turner syndrome

Answer

Profile 1 matches Müllerian agenesis. Profile 2 matches complete androgen insensitivity syndrome. Profile 3 matches Kallmann syndrome. Profile 4 matches Turner syndrome.
Each profile distinctly aligns with a classic etiology of primary amenorrhea, correctly mapping genetic, anatomical, and endocrinological findings to their underlying pathophysiology.

Step-by-Step Solution

1
Differentiate profiles based on the presence or absence of a uterus.
Profiles 1 and 2 describe patients with an absent uterus. Profiles 3 and 4 describe patients with a present uterus.
The presence of a uterus indicates that anti-Müllerian hormone (AMH) was not present during fetal development, guiding the differential diagnosis into discrete categories.
2
Evaluate the karyotype and hair distribution for patients with an absent uterus.
Profile 1 (46,XX, present hair) indicates Müllerian agenesis. Profile 2 (46,XY, absent hair) indicates complete androgen insensitivity syndrome.
Both conditions cause primary amenorrhea and absent uterus with normal breasts, but CAIS is characterized by androgen receptor resistance leading to absent pubic/axillary hair.
3
Evaluate gonadotropin levels and physical features for patients with a present uterus and absent breasts.
Profile 3 features low FSH/LH and anosmia, pointing to a central defect (Kallmann syndrome). Profile 4 features high FSH/LH and a 45,X karyotype, pointing to primary ovarian insufficiency (Turner syndrome).
Low FSH/LH indicates a hypothalamic-pituitary issue (hypogonadotropic), while high FSH/LH indicates gonadal failure (hypergonadotropic) due to loss of negative feedback.

Key Concept

The diagnostic algorithm for primary amenorrhea relies on pelvic ultrasound to evaluate for a uterus, followed by FSH and LH measurement to differentiate central from gonadal failure, and karyotyping to identify specific genetic syndromes.
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Reproductive Endocrinology and Infertility

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