Prenatal diagnosis and genetic analysis of a female fetus with 46, XX and positive SRY gene / 中华围产医学杂志

We report a case of a pregnant woman with 46,XX karyotype and positive sex-determining region on the Y chromosome ( SRY) gene and her female fetus. Ultrasound examination at 12 +6 gestational weeks indicated a thickened fetal nuchal translucency, and 46, XX with a positive SRY gene was detected in the fetus through quantitative fluorescent-polymerase chain reaction and amniotic fluid karyotype. However, the ultrasound showed that the gender of the fetus was female, which was inconsistent with the phenotype of male syndrome with 46, XX combining positive SRY gene. The fluorescent in situ hybridization (FISH) revealed that the short arm of the Y chromosome translocated to the long arm of one of the X chromosomes, namely Yp11.3-Xq28. In addition, a copy number variation at Yp11.31p11.2 copy (about 1 MB) was found by chromosomal microarray analysis, which validated the result of FISH and was consistent with the mother. After genetic counseling, the parents chose to continue the pregnancy to full term, and no abnormalities were found in the infant during the follow-up.

Paciente masculino con cariotipo 46 XX negativo para el gen SRY y sin ambigüedad genital: reporte de un caso / Male patient 46, XX SRY -negative and unambiguous genitalia: A case report

En la mayoría de los casos, la diferenciación sexual masculina ocurre con la participación del gen SRY. Sin embargo, se pueden presentar otros genotipos excepcionales, como en el caso que se presenta en este reporte. Se trata de un paciente adulto de sexo masculino atendido en el Servicio de Paternidades del Instituto de Genética de la Universidad Nacional de Colombia. Se le hicieron los análisis del gen de la amelogenina y de repeticiones cortas en tándem (Short Tandem Repeat, STR) específicas para el gen SRY con estuches comerciales de identificación humana, así como los de cariotipo convencional e hibridación in situ fluorescente del SRY, y el estudio de microdeleciones del cromosoma Y mediante reacción en cadena de la polimerasa (PCR). Se le hizo la evaluación clínica y se le brindó asesoramiento genético. El paciente no presentaba ambigüedad genital, su cariotipo era 46 XX, y el perfil molecular era negativo para el gen SRY y positivo para el ZFY. Se le diagnosticó un trastorno de diferenciación sexual 46 XX testicular no sindrómico, una rara condición genética. Solo el 20 % de los pacientes con este diagnóstico son negativos para SRY y exhiben perfiles moleculares diversos. La información disponible parece indicar que el ZFY está relacionado con la diferenciación sexual masculina, aún en ausencia del gen SRY.

In most cases, male sexual differentiation occurs with SRY gene mediation. However, exceptional genotypes have been identified, as shown in this paper. This was a male adult patient seen at the Servicio de Paternidades, Instituto de Genética, Universidad Nacional de Colombia. The following procedures were carried out: Amelogenin gene and short tandem repeat analyses using human identification commercial kits, conventional karyotype, SRY fluorescent in situ hybridization, PCR analysis for Y chromosome microdeletions, clinical evaluation, and genetic counseling. We present an adult male with unambiguous genitalia, karyotype 46,XX, and an SRY negative and ZFY positive molecular profile. The diagnosis of nonsyndromic 46,XX testicular disorder of sex development (DSD) -a rare genetic condition- was established. Only 20 % of similarly diagnosed patients are SRY negative and exhibit diverse molecular profiles. Until now, available evidence seems to indicate that, even in the absence of SRY, the ZFY factor is involved in male sexual differentiation.

Hyperbaric oxygen combined with Schwann cells transplantation for spinal cord injury in rats:electrophysiological and functional changes of the hind limbs / 中国组织工程研究

BACKGROUND:Hyperbaric oxygen therapy can improve the microenvironment of the injured spinal cord, and hyperbaric oxygen combined with Schwann cel transplantation is expected to improve the therapeutic efficacy on spinal cord injury. OBJECTIVE:To investigate the effect of Schwann cel transplantation plus hyperbaric oxygen on the neural functional recovery of rats with spinal cord injury. METHODS:A total of 80 female SD rats with spinal cord injury were randomized into 4 groups, with 20 in each group:blank control group, injection of L-DMEM via the tail vein at 6 hours after modeling;cel transplantation group, injection of 3×106 RESULTS AND CONCLUSION:The motor function of the lower limbs was better in the combination group than the cel transplantation and hyperbaric oxygen groups, as wel as better in the cel transplantation group and Schwann cel suspension via the tail vein at 6 hours after modeling;hyperbaric oxygen group, hyperbaric oxygen therapy at 1 hour after modeling;combination group, combined therapy of Schwann cel transplantation and hyperbaric oxygen. Inclined plane test, modified Tarlov score, Basso-Beattie-Bresnahan score for motor function evaluation of rat hind limbs were performed and measured at 1, 3 days, 1, 2, 3, 4 weeks after treatment. SRY gene expression in the spinal cord was measured at 4 weeks after transplantation using PCR method. Horseradish peroxidase tracer and electroneurophysiology detection was done at 8 weeks after transplantation.hyperbaric oxygen groups than the blank control group. SRY expression was detected in the cel transplantation group and combination group, but not in the blank control group and hyperbaric oxygen group. The number of nerve fibers positive for horseradish peroxidase was higher in the combination group than the cel transplantation and hyperbaric oxygen groups fol owed by the blank control group, and there were significant differences between different groups (P<0.01). In addition, the latencies and amplitudes of somatosensory evoked potential and motor evoked potential in the combination group were also better than those in the other groups (P<0.05 or P<0.01). These findings indicate that the combined therapy of Schwann cel transplantation and hyperbaric oxygen can promote the synaptic regeneration, improve limb motor function and electrophysiological function in rats with spinal cord injury, which is superior to hyperbaric oxygen or Schwann cel transplantation alone.

Diagnóstico prenatal de mosaicismo 45,X/46,XX con presencia del gen SRY. Presentación de un caso / Prenatal Diagnosis of 45,X/46,XX Mosaicism with Presence of SRY Gene. A Case Report

El cariotipo más frecuente del Síndrome de Turner es 45,X, aunque también puede presentarse como mosaico 45,X/46,XX. En el Centro Provincial de Genética Médica de Cienfuegos se le realizó la amniocentesis a una gestante de 42 años de edad, detectándose un mosaico de Síndrome de Turner (45,X/46,XX). Por ultrasonido se diagnosticó un varón, por lo que se envió una muestra de líquido amniótico al Centro Nacional de Genética Médica para corroborarlo y se indicó realizar estudio del gen SRY, cuyo resultado fue positivo. La gestante decidió interrumpir el embarazo. El reporte de anatomía patológica informó de cadáver de feto de 25,3 semanas de gestación, con pene y bolsas escrotales morfológicamente normales, con alteraciones por quistificación e hipoplasia de la próstata y vesículas seminales y ausencia testicular. En la literatura se reportan casos de varones 46,XX, como poco frecuentes y se refieren menos aún aquellos donde se combina un mosaico 45,X/46,XX con presencia del gen SRY, hecho en que radica el interés del caso. En este artículo se expone el resultado de un diagnóstico prenatal de esta aberración cromosómica de tan baja frecuencia.

The most common karyotype of the Turner syndrome is 45,X, although it may occur as mosaic 45,X/46,XX. In the Provincial Medical Genetics Center, a 42-year-old pregnant woman underwent an amniocentesis which led to the detection of mosaic Turner Syndrome (45,X/46,XX). A male was diagnosed through ultrasound and a sample of amniotic fluid was sent to the National Medical Genetics Center to confirm it. A study of the SRY gene was completed and the result was positive. The patient decided to terminate the pregnancy. The pathology report showed a fetal corpse of 25, 3 weeks of gestation, with penis and morphologically normal scrotal sacs, presenting alterations by cysts and hypoplasia of the prostate and seminal vesicles as well as testicular absence. In the literature, cases of XX males are considered uncommon while those combining a mosaic 45, X/46, XX with a SRY gene are less addressed; and therein lies the importance of this case. This article presents the results of a prenatal diagnosis of this rare chromosomal aberration.

Clinical application of noninvasive prenatal diagnosis using cell free fetal DNA in maternal plasma / 中华妇产科杂志

Objective To investigate the clinical value of non-invasive prenatal diagnosis using cell free fetal DNA(cff-DNA)in maternal blood.Methods From Sep.2010 to Mar.2012,103 pregnant women who came to Henan Province People's Hospital in the first trimestcr for prenatal diagnosis of scx-linked inherited diseases were included in the first trimester group.From Oct.2010 to Jan.2012,205 pregnant women undergoing amniotic fluid sampling for fetal karyotype analysis in the same hospital were included in the second trimester group.Real time quantitative PCR and fluorescent PCR were used to detect sex determining region of Y chromosome gene(SRY)and amelogenin gene(AML)on cff-DNA of the first trimester group.Moreover,12 Y chromosome STR loci analysis were performed for 33 male fetuses and their fathers.Massively Parallel Signature Sequencing(MPSS)was used for aneuploidy analysis in cff-DNA of the second trimester group.Results(1)In the first trimester group,there were 53 SRY positive and 50 SRY negative.Compared with the results of cff-DNA of chorionic villus samples,there was one SRY false positive and one false negative results,with a sensitivity of 98％ and specificity of 98％.For the AML gene test,there were two PCR products of male fetuses:102 bp fragment originating from X chromosome(AML X)and 108 bp fragment from Y chromosome(AML Y);but only AML X was found in products from female fetuses.In the first trimester group,102 bp and 108 bp fragments were detected in 52 cases,and only 102 bp fragment was found in the other cases.Compared to AML results from chorionic villus samples,there were 2 false negative results,with a sensitivity of 96％ and specificity of 100％.(2)For cff-DNA with plasma SRY over 30 copy/ml,Y STR loci were analyzed on cff-DNA of 33 fetuses and their fathers.The Y STR loci less then 200 bp were successfully detected,while Y STR loci with PCR products between 200-300 bp showed low signal or could not be amplicated;and no PCR products more than 300 bp were detected from cff-DNA.Comparing the detected Y STR loci of cff-DNA to the fathers,32 fetuses were concordant with their fathers'.Exogenous contamination was found in the rest one sample.(3)In the second trimester group,6 fetuses with abnormal karyotype(two trisomy 21,three trisomy 18 and one 45,XO)were detected by cff-DNA and were proved by karyotype analysis.Moreover,the MPSS results of cff-DNA revealed one 45,Y and one trisomy 16 whose karyotype analysis showed normal results.And in one case,MPSS suggested less chrX or chrY,that was proved to be 47,XYY by karyotype analysis.Conclusions(1)Cff-DNA in maternal blood can be used to determine fetal gender in early prenancy with considerable sensitivity and specificity.But the trace cff-DNA and the high maternal DNA background might have impact on the result.(2)Analysis of cff-DNA in maternal blood of the second trimester women showed that MPSS could be used for prenatal screening of trisomy 21 and trisomy 18.However,further research should be done for other chromosomes aneuploidy detection.

Y chromosome in Turner syndrome: review of the literature / Cromossomo Y na síndrome de Turner: revisão da literatura

Turner syndrome (TS) is one of the most common types of aneuploidy among humans, and is present in 1:2000 newborns with female phenotype. Cytogenetically, the syndrome is characterized by sex chromosome monosomy (45,X), which is present in 50-60 percent of the cases. The other cases present mosaicism, with a 45,X cell line accompanied by one or more other cell lines with a complete or structurally abnormal X or Y chromosome. The presence of Y-chromosome material in patients with dysgenetic gonads increases the risk of gonadal tumors, especially gonadoblastoma. The greatest concern is the high risk of developing gonadoblastoma or other tumors and virilization during puberty if chromosome Y-specific sequences are present. The role of the Y chromosome in human oncogenesis is still controversial. Even though gonadoblastoma is a benign tumor, it can undergo transformation into invasive dysgerminoma in 60 percent of the cases, and also into other, malignant forms of germ cell tumors. Although some authors have questioned the high incidence of gonadoblastoma (around 30 percent), the risk of developing any kind of gonadal lesion, whether tumoral or not, justifies investigation of Y-chromosome sequences by means of the polymerase chain reaction (PCR), a highly sensitive, low-cost and easy-to-perform technique. In conclusion, mosaicism of both the X and the Y chromosome is a common finding in TS, and detection of Y-chromosome-specific sequences in patients, regardless of their karyotype, is necessary in order to prevent the development of gonadal lesions.

A síndrome de Turner (ST) é uma das aneuploidias mais comuns em humanos e está presente em 1:2000 recém-nascidas com fenótipo feminino. Citogeneticamente, a síndrome é caracterizada por uma monossomia de cromossomo sexual (45,X) em 50-60 por cento dos casos. Os demais casos apresentam mosaicismo com uma linhagem celular 45,X acompanhada de outra(s) com o cromossomo X ou Y íntegros ou com alterações estruturais. A presença de material do cromossomo Y em pacientes com gônadas disgenéticas aumenta o risco de tumores gonadais, especialmente gonadoblastoma. A consideração mais importante diz respeito ao elevado risco de desenvolvimento de gonadoblastoma ou outros tumores e a virilização na puberdade se sequências cromossomo Y-específicas estiverem presentes. O papel do cromossomo Y na oncogênese dos cânceres humanos ainda é controverso. Apesar de o gonadoblastoma ser um tumor benigno, ele pode transformar-se num disgerminoma invasivo em 60 por cento dos casos e também em outras formas malignas de tumores de células germinativas. Apesar de alguns autores questionarem a alta incidência (em torno de 30 por cento) de gonadoblastoma, o risco do desenvolvimento de qualquer tipo de lesão gonadal, tumoral ou não, justifica a pesquisa de sequências do cromossomo Y por PCR (reação de polimerase em cadeia), técnica de alta sensibilidade, baixo custo e fácil execução. Em conclusão, o mosaicismo cromossômico tanto do X como do Y é um fato comum na ST e a detecção de sequências cromossomo Y-específicas nas portadoras, independentemente do seu cariótipo, é necessária para prevenir o desenvolvimento de lesões gonadais.

Detection for fetal DNA in maternal plasma by fluorescence quantitative polymerase chain reaction / 中华围产医学杂志

Objective To investigate the fluorescence quantitative PCR (FQ-PCR) based on TaqMan-MGB( Minor Groove Binder) technique for quantification of fetal DNA in maternal plasma and its variation during pregnancy. Methods Maternal DNA extracted from 237 plasma samples obtained from 30 pregnant women (5-40 gestational weeks and post delivery). The TaqMan-MGB probe and SRY primers were designed to amplify the SRY gene sequence of Y chromosome in maternal plasma by FQ-PCR. Results This system was sensitive enough to detect a male DNA among 20 000 female DNA. Fetal DNA can be detected in maternal plasma as early as 6+6 weeks of gestation and increased with the pregnant progress with the peak level at the third trimester. Between 24- 48 h after delivery, the SRY gene was negative in maternal plasma. The percentage of fetal DNA concentration in maternal total plasma DNA was 4. 88% in the first trimester, 6. 10% in the second and 4. 77% in the third trimester. The SRY positive signal was obtained from samples of 13 women bearing male fetuses and no signal was detected for all of the 17 women bearing female fetuses. Conclusions The FQ-PCR for quantification of fetal DNA in maternal plasma is highly sensitive, specific and reliable. Fetal DNA does present in maternal plasma at a higher concentraton. FQ-PCR may be useful in nonin-vasive prenatal diagnosis.