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Difficulty: Very hardReproductive Endocrinology and Infertility

Match each clinical and laboratory profile of a patient presenting with primary amenorrhea to the most likely underlying diagnosis.

  • Profile 1: 16-year-old with primary amenorrhea, absent breast development, and absent pubic hair. Pelvic ultrasound reveals a small uterus. Blood pressure is 155/95 mmHg, and serum potassium is 2.9 mEq/L. Labs show elevated FSH and LH.17-alpha-hydroxylase deficiency
  • Profile 2: 16-year-old with primary amenorrhea, normal breast development, and absent axillary and pubic hair. Pelvic ultrasound reveals an absent uterus. Labs show testosterone in the normal adult male range and elevated LH.Complete androgen insensitivity syndrome (CAIS)
  • Profile 3: 16-year-old with primary amenorrhea, normal breast development, and normal pubic hair. Pelvic ultrasound reveals an absent uterus and normal ovaries. Labs show normal female levels of testosterone, FSH, and LH.Müllerian agenesis (Mayer-Rokitansky-Küster-Hauser syndrome)
  • Profile 4: 15-year-old with primary amenorrhea, absent breast development, and normal pubic hair. She has a history of cleft lip repair and cannot distinguish the smell of coffee. Pelvic ultrasound reveals a normal uterus. Labs show low FSH and LH.Kallmann syndrome
  • Profile 5: 16-year-old with primary amenorrhea, absent breast development, and normal pubic hair. She is at the 3rd percentile for height. Pelvic ultrasound reveals a small uterus and streak ovaries. Labs show markedly elevated FSH and LH.Gonadal dysgenesis (Turner syndrome)

Answer

Profile 1 matches 17-alpha-hydroxylase deficiency; Profile 2 matches Complete androgen insensitivity syndrome (CAIS); Profile 3 matches Müllerian agenesis; Profile 4 matches Kallmann syndrome; Profile 5 matches Gonadal dysgenesis (Turner syndrome).
The diagnosis of primary amenorrhea relies on evaluating breast development (estrogen presence), pubic hair (androgen presence), pelvic ultrasound (Müllerian structures), and FSH/LH levels. Profile 1's unique triad of absent sex steroids, hypertension, and hypokalemia defines 17-alpha-hydroxylase deficiency. Profile 2's absent pubic hair despite male-level testosterone points to androgen insensitivity. Profile 3's entirely normal female phenotype minus a uterus is classic Müllerian agenesis. Profile 4's hypogonadotropic hypogonadism with anosmia is Kallmann syndrome. Profile 5's hypergonadotropic hypogonadism with short stature and normal adrenarche defines Turner syndrome.

Step-by-Step Solution

1
Evaluate Profile 1 for presence of uterus and secondary sexual characteristics.
Uterus is present, breasts and pubic hair are absent, indicating a lack of both estrogens and androgens. Concomitant hypertension and hypokalemia point to a steroidogenesis defect.
17-alpha-hydroxylase deficiency shunts steroid precursors to mineralocorticoids, causing hypertension and hypokalemia, while preventing synthesis of sex steroids.
2
Evaluate Profile 2 for presence of uterus and secondary sexual characteristics.
Absent uterus, normal breasts, absent pubic hair, and male-range testosterone indicate a 46,XY disorder of sex development with androgen resistance.
In CAIS, tissues cannot respond to androgens (no pubic hair), but normal aromatization of high testosterone levels produces enough estrogen for breast development.
3
Evaluate Profile 3 for presence of uterus and secondary sexual characteristics.
Absent uterus but completely normal secondary sexual characteristics and female hormones indicate a structural anomaly.
Müllerian agenesis involves the failed development of the uterus and upper vagina, but the ovaries (which dictate hormones and secondary characteristics) are unaffected.
4
Evaluate Profile 4 for hormone levels and associated anomalies.
Low FSH/LH with anosmia and cleft lip indicates a central defect.
Kallmann syndrome is caused by the failure of GnRH-secreting neurons to migrate, often accompanied by anosmia and midline defects.
5
Evaluate Profile 5 for hormone levels, secondary characteristics, and physical stigmata.
Elevated FSH/LH with absent breasts but normal pubic hair, combined with short stature, indicates primary ovarian insufficiency with normal adrenal function.
Turner syndrome (45,X) causes accelerated follicular atresia leading to streak ovaries (lack of estrogen) and short stature, but adrenal androgens (responsible for pubic hair) are spared.

Key Concept

Differential diagnosis of primary amenorrhea using the presence or absence of secondary sexual characteristics, the uterus, and corresponding endocrine profiles.
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Topics

Reproductive Endocrinology and Infertility

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