Prenatal and postnatal characterization of Y chromosome structural anomalies by molecular cytogenetic analysis

We describe three cases in which we used fluorescence in situ hybridization (FISH), polymerase chain reaction (PCR) and comparative genomic hybridization (CGH) to characterize Y chromosome structural anomalies, unidentifiable by conventional G-banding. Case 1 was a 46,X,+mar karyotype; FISH analysis revealed an entire marker chromosome highlighted after hybridization with the Y chromosome painting probe. The PCR study showed the presence of Y chromosome markers AMG and SY620 and the absence of SY143, SY254 and SY147. CGH results confirmed the loss of Yq11.2-qter. These results indicated the presence of a deletion: del(Y)(q11.2). Case 2 was a 45,X [14]/46,XY[86] karyotype with a very small Y chromosome. The PCR study showed the presence of Y chromosome markers SY620 and AMG, and the absence of SY143, SY254 and SY147. CGH results showed gain of Yq11.2-pter and loss of Yq11.2-q12. These results show the presence of a Yp isodicentric: idic(Y)(q11.2). Case 3 was a 45,X,inv(9)(p11q12)[30]/46,X,idic(Y)(p11.3?),inv(9)(p11q12)[70] karyotype. The FISH signal covered all the abnormal Y chromosome using a Y chromosome paint. The PCR study showed the presence of Y chromosome markers AMG, SY620, SY143, SY254 and SY147. CGH only showed gain of Yq11.2-qter. These results support the presence of an unbalanced (Y;Y) translocation. Our results show that the combined use of molecular and classical cytogenetic methods in clinical diagnosis may allow a better delineation of the chromosome regions implicated in specific clinical disorders.     

A non-mosaic isodicentric Y chromosome resulting from breakage and fusion at the Yq pseudo-autosomal region in a fetus

The dicentric Y chromosomes are the most commonly found in the structural aberration of Y chromosome. If the dicentric chromosome has completely symmetric arms, it is considered an isodicentric chromosome. The sites of breakage and fusion at Yp and Yq are variable, but breakage and fusion at the pseudo-autosomal region has never been reported. Herein we reported identification de novo isodicentric (Yq12) in a fetus. The fusion occurred at Yq pseudo-autosomal region very close the telomere and resulted in duplication of Y chromosome. The baby was grossly normal at birth. In conclusion, isodicentric Y chromosome could result from breakage and fusion at the Yq pseudo-autosomal region.     

Microphthalmia with linear skin defects (MLS) syndrome evaluated by prenatal karyotyping, FISH and array comparative genomic hybridization

OBJECTIVE: To explore the utility of comparative genomic hybridization to BAC arrays (array CGH) for prenatal diagnosis of microphthalmia and linear skin defects syndrome. METHODS: We used karyotype analysis, FISH and array CGH to investigate an X;Y translocation. Replication studies were done on cultured amniocytes and lymphoblasts. RESULTS: We describe a severe case of MLS syndrome that presented prenatally with multiple anomalies including cystic hygroma, microphthalmia, intrauterine growth restriction and a complex congenital heart defect. Cytogenetic analysis of amniocytes revealed an unbalanced de novo translocation between chromosomes X and Y [karyotype 46,X,der(X)t(X;Y)(p22.3;q11.2).ish der(X)(DXZ1+,DMD+,KAL-,STS-,SRY-),22q11.2 (Tuple1 x 2)]. MLS diagnosis was made at birth and the prenatal karyotype was confirmed. Replication studies showed the derivative X chromosome was the inactive X. Array CGH confirmed the X and Y imbalances seen in the karyotype and also showed twelve BACs in the MLS region were deleted as a result of the translocation. FISH with BAC clones verified the array findings and placed the X breakpoint in Xp22.2, resulting in the amended karyotype, 46,X,der(X)t(X;Y)(p22.2;q11.2).ish der(X)(DXZ1+,DMD+,KAL-,STS-,SRY-),22q11.2(Tuple1 x 2) arr cgh Xp22.33p22.2(LLNOYCO3M15D10 -->GS1-590J6)x 1,Yq11.222q23(RP11-20H21-->RP11-79J10)x 1. CONCLUSION: The sensitivity of array CGH was valuable in detecting monosomy of the MLS critical region. Array CGH should be considered for the prenatal diagnosis of this syndrome.     

Anomalies de structure du chromosome Y et syndrome de Turner

Although specifically male, the human Y chromosome may be observed in female karyotypes, mostly in women with Turner syndrome stigmata. In women with isolated gonadal dysgenesis but otherwise normal stature, the testis determining factor or SRY gene may have been removed from the Y chromosome or may be mutated. In other women with Turner syndrome, the karyotype is usually abnormal and shows a frequent 45,X/46,XY mosaicism. In these cases, the phenotype depends on the ratio between Y positive and 45,X cell lines in the body. When in mosaicism, Y chromosomes are likely to carry structural abnormalities which explain mitotic instability, such as the existence of two centromeres. Dicentric Y isochromosomes for the short arm (idic[Yp]) or ring Y chromosomes (r[Y]) are the most frequent abnormal Y chromosomes found in infertile patients and in Turner syndrome in mosaic with 45,X cells. Although monocentric, deleted Y chromosomes for the long arm and those carrying microdeletions in the AZF region are also instable and are frequently associated with a 45,X cell line. Management of infertile patients carrying such abnormal Y chromosomes must take into account the risk and the consequences of a mosaicism in the offspring.     

Prenatal diagnosis and genetic analysis of X chromosome polysomy 49, XXXXY

We report on the prenatal diagnosis, genetic analysis and clinical manifestations of a 49,XXXXY fetus. A 31-year-old, primigravida woman was referred for genetic counselling at 17 weeks' gestation with the sonographic findings of intrauterine growth retardation, generalized oedema, a large septated cystic hygroma colli measuring 5x4 cm, and abnormal posturing of the lower extremities. Quantitative fluorescent polymerase chain reaction (QF-PCR) with small tandem repeat (STR) markers specific for chromosome X and a pentanucleotide marker X22 for the Xq/Yq pseudoautosomal region PAR2 rapidly detected the X-chromosome polysomy from amniotic fluid cells. This abnormality appeared to arise from successive non-disjunction during maternal meiosis I and meiosis II. Cytogenetic analysis revealed a karyotype of 49,XXXXY. Our case shows that a 49,XXXXY fetus in the second trimester may demonstrate hydrops fetalis and a large septated cystic hygroma colli by prenatal ultrasound. Our case also shows that QF-PCR assays with sex chromosome specific STR markers provide rapid prenatal diagnosis of numerical sex chromosome aneuploidy as well as its genetic cause in fetal cystic hygroma.     

Long-term outcome of fetus with ameliorated cystic hygroma

ObjectiveCystic hygroma often ameliorates or disappears with pregnancy progression. Fetuses/neonates with amelioration, when without chromosomal or major structural abnormality, generally show a favorable outcome at birth. The present study was aimed to clarify the short/long-term outcomes of fetuses/neonates with the amelioration of cystic hygroma during pregnancy.Material and methodsThis was a retrospective observational study. We focused on fetuses with cystic hygroma managed in our institute between January 2006 and June 2019. The infants were followed by pediatricians (neonatologist, pediatric cardiologist, and pediatric neurologist) and pediatric outcomes were retrieved from the medical records up to 3 years old.ResultsOne hundred and seven fetuses with cystic hygroma were included. Of the 107, cystic hygromas ameliorated in 31 fetuses (31/107: 29%). Of the 31, there were 26 livebirths. Half (n = 13) of the 26 fetuses had a good outcome, whereas the remaining half (n = 13) had abnormalities. Various abnormalities were detected in their infancies. A nuchal thickness (diameter of hygroma) of ≥5 mm was significantly correlated with abnormalities (P = 0.047).ConclusionPhysicians should pay attention to fetuses/neonates with ameliorated cystic hygroma. Of those, special attention should be paid to fetuses/neonates with a nuchal thickness at diagnosis ≥5 mm.     

First-trimester cystic hygroma and neurodevelopmental disorders: The association to remember

ObjectiveWe present two prenatal cases of first-trimester cystic hygroma who are later found to suffer from rare genetic syndromes.Case reportBoth of the two pregnant women were showed to have fetal cystic hygroma on ultrasound at the first trimester. Fetal microarray result was normal. Follow-up sonographic examinations showed no structural anomalies. The two pregnancies continued uncomplicatedly to term. However, the two infants developed early neurodevelopmental syndrome within two years of age. Exome sequencing confirmed that one child had Mental retardation, autosomal dominant 23 (MRD23) with a c.646delC (p.Q216Sfs135) variant in SETD5 gene, and the other child had Smith-Magenis syndrome with a c.3103dupC (Q1035Pfs131) variant in RAI1 gene.ConclusionClinicians have to be vigilant when counseling the patient whose fetus has a first-trimester cystic hygroma even with a normal array result and normal sonographic scans. Although they are rare, monogenetic syndromes are possible outcomes.     

Molecular and cytogenetic characterization of extra-structurally abnormal chromosomes (ESACs) found prenatally: outcome and follow-up

A 40-year-old woman underwent amniocentesis at 15.3 weeks of gestation. Chromosome analysis performed using QFQ, DA-DAPI and CBG banding revealed two de novo extra-chromosomal markers (ESACs) in 11 of the 16 colonies analysed. Fluorescence in situ hybridization (FISH) showed that both chromosomes came from the Yq11.22.1 region of the Y chromosome. PCR analysis of genes and STS localized on the Y chromosome excluded the Yp presence specifically of the SRY gene, and most of the euchromatic region of Yq. After extensive genetic counselling and considering both laboratory and second-level ultrasound data, the couple decided to continue the pregnancy. At 37.4 weeks of gestational age, a girl weighing 2750 g was born with an Apgar score of 9/10. A blood sample taken from the umbilical cord showed three cellular lines: mos47,XX, +mar1 ish.der (Y)(wcpY+) [21%]/48,XX, +mar1 ish.der (Y)(wcpY+), +mar2 ish.der (Y)(wcpY+) [41%]/46,XX [38%]. One year after birth, the baby was developing normally and had normal psychomotorial activity.     

Cystic hygroma and lymphangioma: associated findings,perinatal outcome and prognostic factors in live-born infants

Objectives We aimed to determine associated ultrasonographic findings, chromosome abnormalities and the prognostic factors of cystic hygromas in live-born infants. Methods We reported a series of 57 cystic hygroma cases, who were diagnosed in the first and the second trimester of pregnancy by means of the ultrasonographic morphology of cystic hygroma, associated structural abnormalities, karyotype analysis and the autopsy findings. Survivors were followed for their fetal outcome and prognosis. Results There were 57 new cases of cystic hygroma among 8,155 screenings (0.7%). 35 of the cases (61.4%) were nonseptated and 22 of the cases (38.6%) were septated cystic hygroma. Chromosomal abnormalities were found in 23 of the cases (40.3%). The most common abnormality in nonseptated cystic hygroma was trisomy 21 (8 cases, 25%) and in septated cystic hygroma was Turner syndrome (4 cases, 21.1%). The most common associated structural malformations were cardiac abnormalities (in 7 cases, 20%) in nonseptated cystic hygroma cases and nonimmune hydrops (in 12 cases, 54.5%) in septated cystic hygroma cases. Overall survival was poor; only one case of septated cystic hygroma with axillary location and seven cases of nonseptated cystic hygroma, of whom two died in the neonatal period, were alive (10.5%). This study had 80% power to detect 0.03% difference in diagnosis cystic hygroma (α = 0.05, β = 0.80). Conclusion Fetuses with cystic hygroma are at high risk for adverse outcome. Prenatal diagnosis with invasive procedures should be done in order to inform the parents in detail. Axillary location of the hygroma and the depth of invasion had prognostic importance.     

Molecular cytogenetic characterization of 16p11.2 microdeletions with diverse prenatal phenotypes: Four cases report and literature review

ObjectiveChromosome 16p11.2 deletions have been recognized as a genetic disorder with well-described postnatal phenotypes. However, the prenatal manifestations are atypical for lacking of enough evidence.Case reportFour pregnant women underwent amniocentesis for cytogenetic analysis and chromosomal microarray analysis (CMA) because of various indications for prenatal diagnosis: prenatal ultrasound abnormalities (cases 1, 2 and 4) and the childbearing history of cerebral palsy child (case 3). No overlapping phenotypes were observed in cases 1, 2 and 4, which might indicate phenotypic diversities in prenatal phenotypes for 16p11.2 microdeletion. All four fetuses showed normal karyotypic results while CMA identified 0.303–0.916 Mb microdeletions of 16p11.2, encompassing BP2–BP3 and BP4–BP5 regions separately. According to the parental CMA verification, case 1 carried a maternal inherited duplication in the region of Xp22.33 and a de novo deletion in the region of Xp21.1. All parents opted for the termination of pregnancies based upon genetic counselling.ConclusionOur findings enriched the intrauterine phenotypic features of 16p11.2 microdeletions, which would be beneficial for genetic counselling in clinic. In addition, preimplantation genetic testing was recognized as a first-tier approach for such carriers if they intended to conceive again.     

Maternal GRB10 microdeletion is a novel cause of cystic placenta: Spectrum of genomic changes in the etiology of enlarged cystic placenta

IntroductionThe genetics and pathology of diploid complete and triploid partial hydatidiform moles have been well established. Enlarged cystic placenta often indicates an underlying etiology and is frequently associated with adverse pregnancy outcome. Several imprinted genes are strongly expressed in placental tissues and essential for normal placental growth and development. Disruption of these imprinted genes can lead to abnormal placental pathology and placental stunting or overgrowth. We present the genetic etiologies of five unusual mosaic cases of enlarged cystic placentas and report a novel etiology, mosaicism for deletion of the maternal GRB10 gene.MethodsFive mosaic placental mesenchymal dysplasia cases with discrete populations of “cystic” and “normal” villi and/or atypical p57^KIP2 immunostaining were evaluated by genetic analysis; including G-banded karyotyping, fluorescence in situ hybridization (FISH), whole genome CGH + SNP microarray, conventional Sanger sequencing, and STR microsatellite analysis.ResultsGenetic etiologies ranged from genome-wide changes, including mosaic androgenetic isodisomy and mosaic diandric triploidy, to a novel microdeletion of the maternally-expressed GRB10 gene. An abnormal mosaic population of cells was also detected in the fetus in two cases.DiscussionFour cases were mosaic for either diandric triploidy or an androgenetic cell population, and the enlarged cystic placentas were likely due to an excess of paternally-expressed growth promoting genes and also the absence of maternally-expressed growth restricting genes. Also we identified mosaicism for a novel microdeletion of the maternal GRB10 allele, a potent growth inhibitor, which resulted in placental overgrowth in the cystic area of one placenta. We advocate the use of ancillary techniques to investigate complex mosaic cases of enlarged cystic placentas to discover atypical genetic etiologies and to increase our understanding of the placental genome.     

High-level mosaicism for 45,X in 45,X/46,X,idic(Y)(q11.2) at amniocentesis in a pregnancy with a favorable outcome and postnatal progressive decrease of the 45,X cell line

ObjectiveWe present prenatal diagnosis of high-level mosaicism for 45,X in 45,X/46,X,idic(Y)(q11.2) at amniocentesis in a pregnancy with a favorable outcome and postnatal progressive decrease of the 45,X cell line.Case reportA 36-year-old, gravida 4, para 3, woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 45,X[22]/46,X,idic(Y)(q11.2)[4]. Prenatal ultrasound was unremarkable, and the fetus had normal male external genitalia. Repeat amniocentesis was performed at 20 weeks of gestation, and the second amniocentesis revealed a karyotype of 45,X[24]/46,X,idic(Y)(q11.2)[3]. Simultaneous interphase fluorescence in situ hybridization (FISH) analysis on uncultured amniocytes revealed that 60% (62/103 cells) were Y-deleted cells. After genetic counseling, the parents decided to continue the pregnancy, and a 3020-g male baby was delivered with a body length of 52 cm, normal male genital organs and no phenotypic abnormalities. The karyotypes of cord blood, umbilical cord and placenta were 45,X[20]/46,X,idic(Y)(q11.2)[20], 45,X[31]/46,X,idic(Y)(q11.2)[9] and 45,X[40], respectively. At age one month, FISH analysis on urinary cells and buccal mucosal cells revealed 11.5% (7/61 cells) and 13.6% (16/118 cells), respectively for mosaicism for the Y-deleted cells. At age five month, the karyotype of peripheral blood was 45,X[9]/46,X,idic(Y)(q11.2)[31]. FISH analysis on buccal mucosal cells showed no abnormal Y-deleted cell (0/101 cells). At age 11 month, the karyotype of peripheral blood was 45,X[5]/46,X,idic(Y)(q11.2)[35]. FISH analysis on 102 buccal mucosal cells showed no abnormal signals. The infant was doing well with normal physical and psychomotor development.ConclusionHigh-level mosaicism for 45,X in 45,X/46,X,idic(Y)(q11.2) at amniocentesis can be associated with a favorable outcome and progressive decrease of the 45,X cell line.     

Prenatal diagnosis of a familial Y long-arm and chromosome 15 short-arm translocation inherited from a mother carrier

ObjectiveWe present prenatal diagnosis of a familial Y long-arm and chromosome 15 short-arm translocation inherited from a mother carrier.Case ReportA 34-year-old primigravid woman underwent amniocentesis at 20 weeks of gestation because of advanced maternal age. Amniocentesis revealed a derived chromosome 15 or 15p+ with an additional material on the short arm of chromosome 15. Cytogenetic analysis of the parents revealed that the phenotypically normal mother carried the same 15p+ variant, and the father had a karyotype of 46,XY. Array comparative genomic hybridization (aCGH) analysis on the DNA extracted from cultured amniocytes revealed no genomic imbalance. Polymorphic DNA marker analysis using the DNAs extracted from cultured amniocytes and parental bloods excluded uniparental disomy (UPD) 15. C-banded preparations and metaphase fluorescence in situ hybridization analysis using a Yq12-specific probe showed a positive stain on the 15p+, indicating the origin of Yq on the short arm of the derivative chromosome 15. The karyotype of amniocentesis was 46,XX,der(15)t(Y;15)(q12;p13)mat. The mother had a karyotype of 46,XX,der(15) t(Y;15)(q12;p13). At 39 weeks of gestation, a 3006-g healthy female baby was delivered with no phenotypic abnormality. During follow-up at age six months, she manifested normal physical and psychomotor development.ConclusionPrenatal diagnosis of a 15p+ variant should include a differential diagnosis of genomic imbalance and UPD 15, and aCGH and polymorphic DNA marker analyses are useful under such a circumstance.     

Turner综合征Y染色体物质嵌合分子遗传学研究

摘要：目的　分析Turner综合征（TS）患儿Y染色体物质及衍生物嵌合发生的情况，为TS患儿诊断后的监测提供科学建议，改善国内TS监测和保健管理的现状。方法　选取2006年2月至2007年8月在重庆医科大学附属儿童医院诊断为TS患儿30例，进行基因组DNA 的Y编码睾丸特异性蛋白基因（TSPY）、 Y染色体中心着丝粒DYZ3重复序列（DYZ3 ）和Y性别决定区域（SRY）3个Y染色体特异序列多聚酶链反应（PCR）检测，反应结果阳性的病例补充SRY探针原位荧光杂交（FISH）分析。结果　基因组DNA 的PCR结果显示，3例患儿的TSPY、 DYZ3扩增均为阳性（10.00%），其中只有1例 SRY 扩增阳性（3.33%）；3例Y染色体物质阳性病例进一步进行FISH研究，结果显示3例SRY杂交信号均为阳性。结论　运用3个Y染色体特异序列的分子遗传学研究，证实Y染色体物质嵌合在TS不少见，每一个TS患儿都应在诊断后进行Y染色体物质的分子遗传学监测。     

Dysgerminoma in a 10-Year Old with 45X/46XY Turner Syndrome Mosaicism

BackgroundTurner syndrome is a genetic disorder resulting from the absence of or structural abnormality of one X chromosome. The presence of Y chromosome material in girls with Turner syndrome confers an increased risk of benign and malignant germ cell tumor and prophylactic bilateral gonadectomy is recommended.CaseA 10-year-old Turner mosaic syndrome (45X/46XY) patient underwent prophylactic gonadectomy after unremarkable preoperative pelvic imaging. Histopathology showed a streak right gonad, and left gonad with gonadoblastoma with limited degree of infiltrating germinoma.Summaryand ConclusionGonadoblastoma and dysgerminoma have been reported in girls with Turner mosaic who carry Y chromosome material. Prophylactic gonadectomy should be considered in these girls without delay.     

Molecular and cytogenetic investigation of Y chromosome deletions over three generations facilitated by intracytoplasmic sperm injection

BACKGROUND: The azoospermic factor (AZF) region is critical for normal spermatogenesis since microdeletions and partial deletions have been associated with infertility. We investigate the diagnostic ability of karyotyping in detecting clinically relevant Y chromosome deletions. The clinical significance of heterochromatin deletions, microdeletions and partial AZFc deletions is also evaluated. METHODS: A patient with a Yq deletion, affected by severe oligoasthenoteratozoospermia, underwent intracytoplasmic sperm injection (ICSI) which resulted in the birth of a healthy baby boy. The patient, his father and his son underwent Y chromosome microdeletion and partial AZFc deletion screening. We also studied the aneuploidy rate in the sperm of the patient by fluorescent in situ hybridization. RESULTS: AZF microdeletions were absent in the family. However, microdeletion analysis confirmed that the Yq deletion was limited to the heterochromatin. We found a partial AZFc gr/gr deletion in all three family members. We observed an increased rate of sex chromosome aneuploidy in the infertile patient. CONCLUSIONS: Cytogenetic analysis was misleading in identifying the Yq breakpoint. Infertility observed in the patient was associated with the gr/gr partial deletion. However, because of the incomplete penetrance of gr/gr deletions, the consequence of the vertical transmission of the deletion through ICSI remains unknown.     

Molecular and Cytogenetic Characterization of Two Azoospermic Patients with X-Autosome Translocation

Purpose : To report two azoospermic patients with reciprocal X–autosome translocations. Methods : Cytogenetic analysis utilizing GTG-banding and Yq microdeletions shown by polymerase chain reaction (PCR) with 12 sequence-tagged site (STS) markers for Y chromosome microdeletions. Results : Cytogenetic analysis showed one man with 46,Y,t(X;19)(q22;q13.3) and the other with 46,Y,t(X;8)(p22;q11). Neither had any Yq microdeletions shown. The patient with 46,Y, t(X;8)(p22;q11) showed a slightly lower than normal testosterone level. By NCBI-Blast search, we found four testis-specific genes, t-complex-associated-testis-expressed 1-like (TCTE1L), Ferritin, heavy polypeptide-like 17 (FTHL17), Testis expressed sequence 13A (TEX13A), and Testis expressed sequence 13B (TEX13B) located near breakpoints on X chromosome. FTHL17, TEX13A, and TEX13B are spermatogonially-expressed, germ-cell-specific genes. Conclusion : This is the first clinical report of azoospermia with reciprocal X–autosome translocations on Xp22 and q22. These translocations on Xp22 and q22 may be direct genetic risk factors for azoospermia.     

Turner Syndrome with Y Chromosome: Spontaneous Thelarche,Menarche, and Risk of Malignancy

Study ObjectiveGirls with Turner syndrome with Y-chromosome material (TS + Y) are assumed to have nonfunctional gonads with increased tumor risk, therefore prophylactic gonadectomy is recommended at diagnosis. In this study we aimed to determine rates of spontaneous thelarche (ST) and spontaneous menarche (SM), and prevalence of gonadal tumor and malignancy in girls with TS + Y, to further inform discussions about gonadectomy.DesignRetrospective review of clinical and pathology data.SettingMulticenter study involving 4 United States children's hospitals.ParticipantsPatients included those with a genetically proven diagnosis of TS + Y and phenotypically female genitourinary exam.InterventionsDemographic characteristics, pubertal development, and gonadal pathology data were abstracted from clinical records. Data for ST were analyzed for patients aged 13 years and older and SM for patients older than 15 years.Main Outcome MeasuresST, SM, prevalence of gonadal tumor, and malignancy.ResultsForty-four patients met inclusion criteria. Nineteen patients were 13 years or older; 8/19 (42%) had ST and reached Tanner stages 2-4 and 2 (11%) had normal ovarian pathology. Nineteen patients were 15 years or older; 2/19 (11%) had SM. Thirty-seven patients underwent gonadectomy; 35 had available pathology results. Gonadoblastoma was identified in 35/7 patients (19%), 1 in situ germ cell neoplasia, and 1 dysgerminoma (3%). One patient with bilateral gonadoblastoma had ST and SM.ConclusionIn this multicenter cohort, 42% of girls with TS + Y entered puberty spontaneously and 11% had SM, supportive of gonadal function. Risk of tumor was similar to previous reports. To achieve informed decision-making, discussions about gonadectomy should incorporate potential for gonadal function and tumor risk.     

Quantitative PCR technique for the identification of microrearrangements of the AZFc region

Purpose: The AZFc region spans about 3.5 Mb and contains many amplicons causing recombination events. Several papers have reported the occurrence of AZFc partial deletions resulting from non allelic homologous recombination (NAHR) (“gr-gr”, “b1-b3” or “b2-b3” deletions), particularly in infertile patients. DAZ genes are present in 4 copies and rearrangements involve a modification of the number of DAZ genes. Methods: In addition to STS plus/minus PCR, we developed a quantitative technique using real time PCR (Q-PCR) to determine the number of DAZ genes. Fourteen DNA controls were selected to validate the use of Q-PCR to detect AZFc microrearrangements, and sperm DNA samples from 30 fertile men were studied. Results: Rearrangements of 14 controls were well identified with Q-PCR, and 2 AZFc partial deletions were detected in fertile men (1 “gr-gr” and 1 “b2-b3”). Conclusion: Q-PCR represents a well-adapted method to detect microrearrangements of the Y-chromosome, complementary to STS analysis.