Reproductive · Year 2 · from Reproductive
Case 1: Turner Syndrome
Clinical Image
Source: Wikipedia - Turner syndrome - CC BY-SA 3.0
Case Presentation
A 16-year-old female is referred to endocrinology for evaluation of primary amenorrhea. She has never had a menstrual period and has minimal breast development. She is of short stature (height 4'8", below the 3rd percentile) despite her parents being of average height. Physical examination reveals Tanner stage I breast development, sparse pubic hair, a low posterior hairline, a webbed neck, a broad chest with widely spaced nipples, and multiple pigmented nevi. No goiter is palpated. External genitalia appear normal but immature. Laboratory studies show FSH 85 mIU/mL (markedly elevated), LH 42 mIU/mL (elevated), and estradiol <20 pg/mL (low). Karyotype reveals 45,X. Pelvic ultrasound demonstrates a small, infantile uterus and bilateral streak gonads (fibrous tissue without follicles). Echocardiogram shows a bicuspid aortic valve without significant stenosis or regurgitation. The diagnosis is Turner syndrome with gonadal dysgenesis. Treatment is initiated with low-dose estrogen to induce pubertal development, with gradual dose escalation and eventual addition of progesterone for cyclic withdrawal bleeding. The patient is counseled about infertility and the option of donor egg IVF in the future.
Key Learning Points
- Turner syndrome (45,X) is the most common sex chromosome abnormality in females, characterized by short stature, gonadal dysgenesis, and variable somatic features
- Streak gonads result from accelerated oocyte loss; without functional ovaries, puberty does not occur spontaneously
- Elevated FSH with low estradiol (hypergonadotropic hypogonadism) confirms ovarian failure
- Cardiovascular abnormalities (bicuspid aortic valve, coarctation of the aorta) require screening; renal anomalies are also common