SRY和maspin基因对胎儿游离DNA的检测效率

目的:探讨应用非性别依赖的表观遗传学标记代替SRY基因检测孕妇血浆中胎儿游离DNA的可行性。方法:分别以SRY基因和不同甲基化状态的maspin基因序列为标记对孕妇和非妊娠女性血浆中的游离DNA进行PCR和甲基化PCR检测,并对结果进行统计学分析。结果:孕男胎孕妇血浆DNA标本中SRY基因的检出率为93.9%。u-maspin(maspin基因的非甲基化序列)仅在妊娠组中被检测出,检出率88.3%。两检出率间的差异不具有统计学意义。m-maspin(maspin基因的甲基化序列)在妊娠组和非妊娠组中的检出率无差异。结论:u-maspin基因可作为非性别依赖的胎儿DNA特异性标志物,相对于以SRY基因作为标志物有助于扩大非创伤性产前诊断的临床应用范围。     

性反转综合征的细胞遗传学1例分析

目的: 探讨性反转综合征发病的可能原因。方法: 运用人类外周血淋巴细胞常规染色体核型并结合相关文献资料进行分析。结果: 分析30个中期分裂相,核型均为46,XY。结论: 该女性患者为46,XY男性性反转综合征;SRY基因的突变或缺失以及SOX基因的突变是导致性反转综合征的主要原因。     

Comparison of morphological and molecular genetic sex-typing on mediaeval human skeletal remains

Archaeological excavations conducted at an early mediaeval cemetery in Volders (Tyrol, Austria) produced 141 complete skeletal remains dated between the 5th/6th and 12th/13th centuries. These skeletons represent one of the largest historical series of human remains ever discovered in the East Alpine region. Little historical information is available for this region and time period. The good state of preservation of these bioarchaeological finds offered the opportunity of performing molecular genetic investigations. Adequate DNA extraction methods were tested in the attempt to obtain as high DNA yields as possible for further analyses. Molecular genetic sex-typing using a dedicated PCR multiplex (“Genderplex”) gave interpretable results in 88 remains, 78 of which had previously been sexed based on morphological features. We observed a discrepancy in sex determination between the two methods in 21 cases. An unbiased follow-up morphological examination of these finds showed congruence with the DNA results in all but five samples.     

手术终止妊娠对早孕妇女外周血中游离胎儿DNA的影响

目的检测在孕早期手术终止妊娠是否会对母体外周血浆中的胎儿DNA水平造成影响。方法选择孕6~9w妇女36例(自愿要求终止妊娠,无禁忌症,胎儿性别为男性),在其终止妊娠前后分别采取外周静脉血5m l,对其血浆中的游离胎儿DNA的SRY基因行荧光定量分析。结果在36例血浆标本中,术前有31例检测到胎儿DNA,术后全部检测到胎儿DNA。其浓度平均分别为62.40±21.70(31.80~128.00Eq/m l),101.04±37.40(58.20~209.70Eq/m l),术前与术后胎儿DNA含量有统计学差异(P<0.01)。结论①孕妇外周血中游离胎儿DNA最早在孕45天即可检测到。②外周血中游离胎儿DNA的水平在妊娠终止后很快升高。③孕妇外周血中的游离胎儿DNA很可能来源于母胎之间出血。     

SRY-negative 46,XX male with normal genitals, complete masculinization and infertility

XX maleness is a rare syndrome with a frequency of 1 in 20,000-25,000 males. XX males exist in different clinical categories with ambiguous genitalia or partially to fully mature male genitalia, in combination with complete or incomplete masculinization. In this study, we report a case of SRY-negative XX male with complete masculinization but infertility. The patient had fully mature male genitalia with descended but small testes and no signs of undervirilization. PCR analysis for SRY, ZFY, Amelogenin, AZFa, AZFb, AZFc genes, a pair of primers from heterochromatic region and six Y-STRs showed the absence of any Y-chromosome-derived material. Absence of SRY gene was confirmed by three independent PCRs for each of two sets of primers covering an increasing length of the gene. Sequence analysis of the coding regions of SOX9 and DAX1 genes did not reveal any mutation. Real-time PCR assay revealed normal copy number for SOX9 gene. Microsatellite analysis showed no evidence of 17q (SOX9 gene) or 22q duplication. Genotyping with X-STRs ruled out the possibility of any deletion on X chromosome. Development of the male phenotype in the absence of SRY probably resulted from the loss of function mutation in some unknown sex-determining gene, which normally inhibits the male pathway, or from a gain of function mutation in a gene downstream to SRY in male pathway.     

A novel SRY missense mutation affecting nuclear import in a 46,XY female patient with bilateral gonadoblastoma

Patients with disorders of sex development (DSD), especially those with gonadal dysgenesis and hypovirilization, are at risk of developing the so-called type II germ cell tumors (GCTs). Both carcinoma in situ and gonadoblastoma (GB) can be the precursor lesion, resulting in a seminomatous or non-seminomatous invasive cancer. SRY mutations residing in the HMG domain are found in 10–15% of 46,XY gonadal dysgenesis cases. This domain contains two nuclear localization signals (NLSs). In this study, we report a unique case of a phenotypical normal woman, diagnosed as a patient with 46,XY gonadal dysgenesis, with an NLS missense mutation, on the basis of the histological diagnosis of a unilateral GB. The normal role of SRY in gonadal development is the upregulation of SOX9 expression. The premalignant lesion of the initially removed gonad was positive for OCT3/4, TSPY and stem cell factor in germ cells, and for FOXL2 in the stromal component (ie, granulosa cells), but not for SOX9. On the basis of these findings, prophylactical gonadectomy of the other gonad was performed, also showing a GB lesion positive for both FOXL2 (ovary) and SOX9 (testis). The identified W70L mutation in the SRY gene resulted in a 50% reduction in the nuclear accumulation of the mutant protein compared with wild type. This likely explains the diminished SOX9 expression, and therefore the lack of proper Sertoli cell differentiation during development. This case shows the value of the proper diagnosis of human GCTs in identification of patients with DSD, which allows subsequent early diagnosis and prevention of the development of an invasive cancer, likely to be treated by chemotherapy at young age.