Hatano Megumi, Fukuzawa Ryuji, Hasegawa Yukihiro
Sex Dev. 2018;12(4):175-179. doi: 10.1159/000489451. Epub 2018 Jun 8.
Some patients with mixed gonadal dysgenesis (MGD), whose prototypical karyotype is 45,X/46,XY, are known to manifest complications characteristic of Turner syndrome. We report a 16-year-old social male with MGD presenting with coarctation of the aorta, one of the common complications for Turner syndrome. At birth, the patient was found to have hypospadias, bifid scrotum, and cryptorchidism. Chromosomal analysis of his lymphocytes revealed the karyotype 45,X[7]/46,X,dic(Y;22)(p11.3;q13.3)[23] (named 45,X/46,X+Y fragment in this article). A left gonadectomy was performed at 1 year of age, and the histology showed a streak gonad with an epithelial cord-like structure compatible with MGD. At the age of 10 years, coarctation of the aorta was discovered by chance, for which the patient underwent surgical repair. The ratio of mosaicism in the gonad and aortic tissues was estimated by FISH with probes to identify the X centromere-specific repeat sequence and Yp11.2. The mosaicism ratio of 45,X/46,X+Y fragment varied among the tissues, with those having a higher ratio being more likely to exhibit the Turner syndrome phenotype. Some 90% of cells in the aortic tissues and 80% in the gonadal tissues lacked a Y chromosome. In conclusion, the mosaicism ratio in the different tissues may explain the phenotypes in MGD.
一些典型核型为45,X/46,XY的混合性性腺发育不全（MGD）患者，已知会表现出特纳综合征的特征性并发症。我们报告一例16岁的社会性别为男性的MGD患者，其患有主动脉缩窄，这是特纳综合征的常见并发症之一。出生时，该患者被发现患有尿道下裂、阴囊分裂和隐睾症。对其淋巴细胞进行染色体分析，结果显示核型为45,X[7]/46,X,dic(Y;22)(p11.3;q13.3)[23]（本文中命名为45,X/46,X+Y片段）。患者1岁时进行了左侧性腺切除术，组织学检查显示为条索状性腺，具有与MGD相符的上皮条索样结构。10岁时，偶然发现主动脉缩窄，患者接受了手术修复。通过使用识别X着丝粒特异性重复序列和Yp11.2的探针进行荧光原位杂交（FISH），估计性腺和主动脉组织中的嵌合率。45,X/46,X+Y片段的嵌合率在不同组织中有所不同，嵌合率较高的组织更有可能表现出特纳综合征的表型。主动脉组织中约90%的细胞和性腺组织中80%的细胞缺乏Y染色体。总之，不同组织中的嵌合率可能解释MGD的表型。
