Androgen insensitivity syndrome 雄激素不敏感综合征

Androgen insensitivity syndrome (AIS), commonly referred to as testicular feminization, is the third most common cause of primary amenorrhea.

雄激素不敏感综合症(AIS)，通常称为睾丸女性化综合征，是导致原发性闭经的第三种常见原因。

Patients with AIS have a normal 46, XY karyotype. Their testes produce both testosterone and anti-mullerian hormone. AIS is caused by genetic abnormality in the androgen receptor gene that results in end organ resistance to the effects of androgen activity (1). This resistance prevents the process of normal masculinization of both internal and external genital structures. These patients are born with normal external female genitalia due to absence of androgen action but have absent internal female genitalia due to the action of anti-mullerian hormone. As a consequence, the vagina is a short, blind pouch.

AIS患者的染色体核型正常，为46，XY。 他们的睾丸既产生睾丸激素又产生抗谬勒氏管激素。AIS是由雄激素受体基因的遗传突变引起的，该突变导致末端器官对雄激素的作用产生抵抗力(1)，从而阻止了内外生殖器结构的正常男性化过程。由于不能表达雄激素作用，AIS患者出生时具有正常的女性外生殖器，但同时又由于抗谬勒氏管激素的作用患者没有形成内生殖器。 因此，患者的阴道呈盲端。

AIS patients have a normal physical exam at birth and typically exhibit normal growth and development in childhood. At puberty, they gain breast development secondary to the peripheral conversion of androgens to estrogen that acts on the breast tissue to stimulate development (2). Given the lack of ovarian progesterone, the areolae and nipples are often small and pale and the breasts lack significant glandular development. Physical exam is also remarkable for absent pubic and axillary hair as a result of lack of androgen effects on peripheral end organs. The testicles may be partially descended and found in the inguinal cavity, or be completely contained within the abdomen.

AIS患者出生时体检正常，通常在幼儿时期表现出正常的生长发育。到青春期时，由于雄激素向雌激素的外周血转换后促进乳房组织刺激发育，AIS患者继而出现乳房发育(2)。由于缺乏卵巢分泌的孕酮激素，通常患者的乳晕和乳头很小且颜色苍白，乳房缺乏明显的腺体发育。体检时可见患者无阴毛或腋毛发育，这是因为缺乏雄激素对周围末梢器官的作用。睾丸可能会部分下降于腹股沟腔内，也可能全部包含在腹部内。

Primary amenorrhea is the usual presenting complaint for patients with AIS. As previously discussed, they have breast development but absent pubic and axillary hair. They will also have an absent cervix and a small, blind ending vaginal canal. Serum testosterone levels will be in the normal male range and the high female range.

AIS患者的主要症状是原发性闭经。如前所述，患者有乳腺发育，但没有阴毛，腋毛或宫颈，只有一条狭窄的盲端阴道管。血清睾丸激素水平处于男性正常范围和女性高范围内。

Treatment of patients with AIS has two major areas of focus (3). The first is creation of a functioning vagina and the second is removal of gonadal tissue to prevent development of a neoplastic process. As with mullerian agenesis, creation of a functional vagina can either be accomplished through progressive dilation or surgical creation of a neo-vagina. Once puberty is complete, the gonads are surgically removed because there is 2%-5% risk of developing testicular cancer after age 25 (4).

治疗AIS综合征主要侧重于两方面(3)，一是进行功能性阴道重建，二是去除性腺组织以防止形成肿瘤。针对谬勒氏管激素缺失导致的无内阴症，可以通过渐进性扩张或阴道再造术来形成功能性阴道。患者度过青春期后，可以通过手术切除性腺，因为患者在25岁后有2%-5%的风险会患上睾丸癌。

References

参考文献

1. Gustafson ML, Donahoe PK. Male sex determination: current concepts of male sexual differentiation. Annu Rev Med 1994; 45: 505.

2. Katz VL, Lentz GM, Labo RA, Gorshenson DM. Comprehensive Gynecology, 5th ed. St. Louis: Mosby; 2007: 933-61.

3. Fritz MA, Speroff L. Clinical Endocrinology and Infertility, 8th ed. Philadelphia: Lippincott Williams & Wilkins, 2010: 435-94.

4. Verp MS, Simpson JL. Abnormal sexual differentiation and neoplasia. Cancer Genet Cytogenet 1987; 25: 191.