Endocrine Abstracts

Primary Amenorrhoea is usually the result of a genetic or anatomical abnormality. Androgen insensitivity syndrome (AIS) is an uncommon cause in which individuals with a 46XY male karyotype are resistant to testosterone due to a defect of the androgen receptor.

A 16-year-old female of non-consanguineous parents presented with primary amenorrhoea. There was no family history of delayed puberty. She was of normal female appearance (height 5′9″, BMI 19 kg/m²). However, both axillary and pubic hair was absent and she had underdeveloped breasts (Tanner Stage 2). External genitalia appeared normal with no clitoromegaly. Her vaginal canal was 5 cm in length.

Biochemical screening revealed elevated levels of LH 38.4 U/l (3–16), FSH 12.9 U/l (0.5–8) and testosterone 17.7 nmol/l (1–2.5) but low levels of serum oestradiol 138 pmol/l. Androstenedione, DHEAS, 17-OH progesterone, prolactin and thyroid function were all normal. A pelvic US confirmed absence of both uterus and ovaries. Subsequent MRI failed to identify any obvious gonadal tissue. Chromosomal screening confirmed a 46XY karyotype.

The findings were consistent with a diagnosis of complete androgen insensitivity syndrome (AIS), an X-linked recessive disorder with an incidence of approximately 1 of 20 000 births. The patient received psychological counselling and support from the AIS Support Group (AISSG, Registered UK Charity) and has coped well with her diagnosis returning to full time education. She has been commenced on low dose oestrogen to enhance her breast development and is being treated with non-surgical pressure dilation to her vaginal canal. Surgical exploration is planned to identify and remove remnant gonadal tissue.