46,XY monozygotic twins with discordant sex phenotype

Objective: To analyze male and female sex differentiation in monozygotic twins.

Design: Retrospective study.

Setting: Multiple academic centers.

Patient(s): A pair of monozygotic twins.

Intervention(s): Skin and blood samples were obtained for DNA analysis and karyotyping.

Main Outcome Measure(s): Mutation within the SRY gene was analyzed by the polymerase chain reaction–single-stranded conformation polymorphism test. Monozygosity was ascertained by short tandem repeat analysis. Karyotypes were studied in blood and skin fibroblasts.

Result(s): SRY was present in both twins, but no mutations were detected in the SRY conserved motif. Monozygosity was confirmed by the use of short tandem repeat analysis in four loci: c-fms, thyroid peroxidase, von Willebrand factor, and tyrosine hydroxylase. The karyotype was 46,XY uniformly in both twins.

Conclusion(s): Monozygotic twins can develop discordant male and female phenotypes despite the presence of a common karyotype and despite the presence of intact testis-determining genes. In the present case, this could be due to mutation or to mosaicism involving occult 45,X cell lines in the dysgenetic gonads.     

A case of complete hypogonadotropic hypogonadism with a mutation in the gonadotropin-releasing hormone receptor gene

OBJECTIVE: To screen for mutations in the GnRH receptor gene in a case of complete hypogonadotropic hypogonadism (HH) with GnRH resistance. DESIGN: Case report. SETTING: A university hospital. PATIENT(S): A male patient with the complete form of HH without anosmia. INTERVENTION(S): Physical examination and laboratory and genetic studies. MAIN OUTCOME MEASURE(S): Gonadotropins at the basal state and after GnRH administration and GnRH receptor DNA sequencing. RESULT(S): A novel missense mutation, localized in the first amino acid of the extracellular loop found in the heterozygous state, and another mutation, Arg(139)His (R139H), located in the conserved aspartate-arginine-serine motif at the junction of the third transmembrane and second intracellular loop of the GnRH receptor, were identified in the homozygous state. Pedigree studies reveal that both parents were heterozygous for R139H, while the mother carried the missense mutation at codon 1(M1T). CONCLUSION(S): GnRH receptor mutations may account for a larger proportion of cases of HH than previously thought. The phenotypic spectrum of HH seems to vary, and this heterogeneity may be related, at least in part, to the degree of impaired biological activity of the mutated GnRH receptor caused by the allelic type of mutations.     

Scant XYqh- testicular cells with normal SRY was enough to differentiate bilateral testes in a 45,X/46,XYqh- patient

OBJECTIVE: It has been established that in 45,X/46,XY individuals predominance of XY or XO gonadal cells determines gonadal differentiation. However, in some cases there is no concordance between the predominance of XY cells and testis differentiation. Here we describe the SRY findings in a patient bearing a 45,X/46,XYqh- karyotype. STUDY DESIGN: The patient presented two small testes (one with spermatogenesis), a male phenotype, and a predominant 45,X karyotype in leukocytes and gonadal cells. PCRs of SRY, ZFY and Yqh were performed on DNA from leukocytes and from left gonadal tissue. SRY-PCR products were purified and sequenced. RESULTS: A normal SRY sequence was found in both tissues. CONCLUSIONS: Despite the predominance of 45,X cells in gonads, some patients in whom SRY is normal can develop testes, probably due to the presence of alternative mechanisms involved in testicular differentiation; however, further gonadal development could be impaired.     

Factors influencing parental decision making in prenatal diagnosis of sex chromosome aneuploidy

OBJECTIVE: To evaluate factors influencing parental decisions toward continuing or terminating a pregnancy with prenatal diagnosis of sex chromosome aneuploidy. METHODS: We reviewed the records of patients with fetuses with sex chromosome aneuploidy between 1990 and 2001. A questionnaire survey of women who chose to terminate such pregnancies was designed to examine aspects of their decision-making process. RESULTS: Forty-nine of 89 pregnancies with sex chromosome aneuploidy were terminated (termination rate 0.55; 95% confidence interval 0.45-0.65). Pregnancies with abnormal ultrasound findings (14/16, 87%), with 45,X or 47,XXY karyotypes (26/36, 72%), and with nonmosaic karyotypes (30/48, 63%) were terminated significantly more often than pregnancies with normal ultrasound findings (35/73, 48%; P <.01), with 47,XXX or 47,XYY karyotypes (4/12, 33%; P <.05), and with mosaic karyotypes (5/25, 20%; P =.01). There was a trend (P =.136) toward a lower rate of termination from 67% to 36% across time, with a significant decrease from 67% to 7% in pregnancies with 47,XXX; 47,XYY; and mosaic karyotypes (P <.01), and no change in cases with 45,X and 47,XXY karyotypes (67% compared with 69%; P = 1.0). Abnormal sexual development and infertility were the greatest parental concerns related to termination. CONCLUSION: Fear of having a child with abnormal sexual development or infertility remains the major determinant of parental decision toward terminating pregnancy, resulting in consistently high termination rates across time in pregnancies with 45,X and 47,XXY karyotypes. In cases with 47,XXX; 47,XYY; and mosaic karyotypes, the declining termination rate across time is a consequence of recent studies reporting normal sexual development and fertility.     

Swyer syndrome with SRY + Y chromosome and rudimentary internal genitalia demonstrating temporary action of antimüllerian hormone in utero: a case report

BACKGROUND: XY gonadal dysgenesis is characterized by streak gonads in phenotypic females without somatic abnormalities. This case demonstrated a hypoplastic uterus, an unlikely finding for the syndrome, suggesting insufficient function of antimüllerian hormone prenatally. CASE: A 20-year-old, female virgin was first seen 2 years earlier complaining of primary amenorrhea. She was 168 cm tall, and secondary sexual characteristics, such as breast development and pubic and axillary hair, were absent on physical examination. Chromosome analysis with fluorescence in situ hybridization revealed 46,XY, and a molecular investigation was undertaken to assess the possibility of a mutation in SRY through DNA sequencing. SRY mutations were absent. Bilateral laparoscopic removal of dysgenetic gonads was performed at another medical center immediately after genetic confirmation for an increased risk of malignancy. When the patient was seen 1 year later, we performed ultrasonography because of no menstrual outflow. Pelvic ultrasonography revealed a hypoplastic uterus (26 x 12 mm) with a rudimentary cervix. CONCLUSION: Clinical phenotypes of different mutations of the Y chromosome, particularly on SRY, may cause Swyer syndrome patients to have a uterus with fertility potential after oocyte donation.     

Analysis of the sex chromosome constitution of sperm in men with a 47, XYY mosaic karyotype by fluorescence in situ hybridization.

OBJECTIVE: To determine the incidence of sex chromosome aneuploidy in the sperm of two men with a 47,XYY/46,XY karyotype. DESIGN: Case report. SETTING: Infertility clinic in a teaching hospital. PATIENT(S): One patient with near normal semen parameters whose wife had a history of miscarriages and one patient with primary infertility and severe oligoasthenozoospermia. INTERVENTION(S): Cytogenetic analysis of peripheral lymphocytes and three-color X/Y/18 fluorescence in situ hybridization analysis of sperm. MAIN OUTCOME MEASURE(S): Analysis of sex chromosome disomy and diploidy rates in sperm. RESULT(S): Both patients had a 47,XYY/46,XY karyotype. The hyperdiploidy rate of patient 1 was 19% and that of patient 2 was 90%. The incidence of disomy XY was significantly elevated in both patients compared with the controls (0.23% and 1.02%, respectively, versus 0.10%). The incidence of disomy YY (0.44% versus 0.10%) was increased only in patient 2, as was the incidence of disomy 18 (0.49% versus 0.09%) and the rate of diploidy (0.83% versus 0.13%). The rate of 24,XX sperm in both patients was not different from that in the controls. CONCLUSION(S): Patients with a 47,XYY mosaic karyotype may be at risk of producing offspring with a hyperdiploid sex constitution. These patients should have their sperm investigated by fluorescence in situ hybridization to determine their particular risks before they undergo intracytoplasmic sperm injection.     

47,XXY female with testicular feminization and positive SRY: a case report

BACKGROUND: Males with a 47,XXY karyotype have the clinical phenotype of Klinefelter syndrome. A few 47,XXY cases with a female phenotype have been reported. These individuals have positive SRY (testis-determining factor). The genetic explanation of this phenomenon is unclear. CASE: A 34-year-old woman presented with testicular feminization and a 47,XXY karyotype. Cytogenetic analysis and fluorescence in situ hybridization suggested that the Y chromosome had a normal structure; the polymerase chain reaction was positive for SRY. CONCLUSION: This is the third reported case of 47,XXY with afemale phenotype in spite of the presence of a Y chromosome and the normal SRY. This suggests that the phenotypic sex in these patients might be due to the involvement of other sex-determining genes.     

Prenatal diagnosis in two families with autosomal, p47(phox)-deficient chronic granulomatous disease due to a novel point mutation in NCF1

OBJECTIVE: Prenatal diagnosis was required in two unrelated families with chronic granulomatous disease (CGD) patients who lacked expression of p47(phox) protein; thus a search for mutations in NCF1 was undertaken. METHODS: Gene scanning was applied to establish the relative number of coding and pseudo-NCF1 genes. PCRs specific for coding NCF1 cDNA and coding NCF1 exon-7 genomic DNA were devised. RESULTS: The normal 1:2 ratio of coding and pseudo-NCF1 genes was found in the patients. Sequencing of the RT-PCR product specific for mRNA from the coding NCF1 genes revealed a novel homozygous G579A mutation in both patients, changing the TGG codon for Trp193 into the TAG stop codon. This mutation was confirmed in genomic DNA. The parents of both patients were found to be heterozygotes for this mutation. In the chorionic villus DNA of the first family a heterozygous G579A mutation was found. Postpartum, functional NADPH oxidase tests were normal. In the second family, this mutation was present in homozygous form in the chorionic villus DNA. Following termination of the pregnancy, the diagnosis of p47(phox)-deficient CGD was confirmed on DNA extracted from fetal blood. CONCLUSION: This is the first report of prenatal diagnosis in p47(phox)-deficient CGD.     

Absence of the testicular determining factor gene SRY in XX true hermaphrodites and presence of this locus in most subjects with gonadal dysgenesis caused by Y aneuploidy.

OBJECTIVES: The purpose of our study was to discover whether the testicular determining factor gene SRY (sex-determining region on Y) is present or absent in XX true hermaphrodites and in subjects with gonadal dysgenesis caused by Y aneuploidy. STUDY DESIGN: We screened five XX true hermaphrodites and 24 subjects with gonadal dysgenesis caused by Y aneuploidy for the presence or absence of SRY. With the polymerase chain reaction technique, the sequence coding the 80 amino acid-conserved motif was amplified. The 0.9 kb Hincll pY53.3 subclone, which covers the open reading frame of SRY, serves as a probe for Southern blot analysis. RESULTS: Test results for all five XX true hermaphrodites were negative for SRY. Conversely, 22 of the 24 individuals with 45,X/46,XY gonadal dysgenesis were positive for SRY, including the 10 subjects with only bilateral streak gonads. CONCLUSIONS: The absence of SRY in XX true hemaphrodites and the presence of SRY in 10 subjects with 45,X/46,XY constitution who harbored only bilateral streak gonads seem to indicate that multiple genes are involved in gonadal differentiation.     

Complete discrepancy between abnormal fetal karyotypes predicted by QF-PCR rapid testing and karyotyped cultured cells in a first-trimester CVS

A chorion villus sample (CVS) biopsied at 11 weeks' gestation for raised nuchal translucency, revealed monosomy X (presumptive 45,X karyotype) by QF-PCR for rapid aneuploidy testing for chromosomes 13, 18, 21, X and Y. Long-term culture gave the karyotype: 47,XY,+ 21[66]/49,XYY,+ 21,+ 21 [22]. This discrepancy prompted redigestion of the combined residual villus fragments from the original QF-PCR assay. The repeat QF-PCR assay identified the presence of trisomy 21 and a Y chromosome consistent with a 47,XY,+ 21 karyotype. A double non-disjunction event early in embryogenesis in a 47,XY,+ 21 conceptus with subsequent cell lineage compartmentalisation of the three observed cell lines (45,X; 47,XY,+ 21 and 49,XYY,+ 21,+ 21) would account for these results. This is the first reported case to describe complete discrepancy at diagnosis between abnormal karyotypes detected by QF-PCR rapid aneuploidy testing and a cultured karyotype in the same CVS.     

Noninvasive prenatal detection of fetal sex chromosome abnormalities using the semiconductor sequencing platform (SSP) in Southern China

BackgroundNoninvasive prenatal testing (NIPT) has been widely used to screen for fetal aneuploidies, including fetal sex chromosome aneuploidies (SCAs). However, there is less information on the performance of NIPT in detecting SCAs.MethodsA cohort of 47,800 pregnancies was recruited to review the high-risk NIPT results for SCAs. Cell-free fetal DNA (cffDNA) was extracted and sequenced. All NIPT high-risk cases were recommended to undergo invasive prenatal diagnosis for karyotyping analysis and chromosome microarray analysis (CMA).ResultsA total of 238 high-risk cases were detected by NIPT, including 137 cases of 45,X, 27 cases of 47,XXX, and 74 cases of 47,XYY/47,XXY. Prenatal diagnosis, including karyotyping analysis and CMA, was available in 170 cases. The positive predictive value (PPV) was 30.00% for 45,X, 70.58% for 47,XXX, and 81.13% for 47,XYY/47,XXY. In addition, 13 cases of sex chromosome mosaicism and 9 cases of sex chromosome CNVs were incidentally found in this study.ConclusionOur study showed that NIPT was reliable for screening SCAs based on a large sample, and it performed better in predicting sex chromosome trisomies than monosomy X. Our study will provide an important reference for clinical genetic counseling and further processing of the results.     

女性表型46,XY性发育障碍的临床、病理特征及遗传学检测

目的:总结女性表型的46,XY性发育障碍患者的临床及病理学特点,对其进行鉴别诊断及遗传学检测,为类似病例的诊断和鉴别诊断提供借鉴资料。方法:回顾分析2010年至2015年在深圳市妇幼保健院行妇科手术的3例46,XY性发育障碍患者的临床资料。将切除的性腺组织进行病理学诊断;提取患者及家属基因组DNA,应用Sanger测序、二代测序方法、MLPA、染色体基因组芯片分析等方法进行遗传学检测以寻找致病基因变异。结果:1例患者为完全型雄激素不敏感综合征(CAIS),病理结果证实一侧隐睾见精原细胞瘤,其AR基因第7外显子检测到移码突变c.2546_2547 insA(p.N849K,fs X32),此突变为已报道导致CAIS的突变方式;1例患者临床诊断为单纯性腺发育不良,性腺病理结果为不成熟的卵巢组织,患者SRY基因的HMG区域检测到c.206TC(p.V69A)突变,此突变未见报道;1例患者临床诊断为单纯性腺发育不良,病理结果为双侧性腺母细胞瘤伴无性细胞瘤,性发育相关基因未检测到明确的致病突变。结论:综合利用多种检测方法对女性表型46,XY性发育障碍患者进行致病基因检测,其中2例患者分别由AR基因、SRY基因突变引起,其中SRY基因c.206TC(p.V69A)为新发现的突变。     

45,X/46,X,del(Yq) sex chromosome mosaicism--analysis of the phenotypic expression

Three female patients with Turner-syndrome (sexual infantilism, short stature and somatic Turner-stigmata) have been analysed cytogenetically by means of different banding techniques. A deletion of the distal heterochromatic band Yq12 of the Y chromosome was observed in a mosaic with a 45,X-cell line, i.e. the karyotype is 45,X/46,X,del(Y)(q12). In order to get information about the phenotypic expression of the 45,X/46,X,del(Yq) mosaicism all previously published cases have been reviewed. Comparing the phenotypes of all 45,X/46,X,del(Yq) mosaic cases three different phenotype categories of sexual development can be distinguished: female individuals with sexual infantilism and Turner-stigmata, individuals with ambiguous genitals, ranging from clitoris hypertrophy of female genitals to hypospadia of males, male individuals, who are infertile (azoospermic). A comparison of the appearance of external genitals with the status of gonads of all patients revealed an unequivocal relationship between the gonad status and the resulting phenotype category. Furthermore, the role of Y-chromosomal loci determining testicular differentiation (biological function of H-Y antigen) for male development has been emphasized. The effect of the 45,X-cell line on the expression of short stature and somatic Turner-stigmata is independent of sexual development. Considering the great phenotypic variability of the 45,X/46,X,del(Yq) mosaicism it seems impossible to deduce a definitive phenotype. This problem is acute in prenatal diagnosis especially.     

Parental decisions regarding prenatally detected fetal sex chromosomal abnormality and the impact of genetic counselling: an analysis of 57 cases in Taiwan

OBJECTIVE: To analyse parental decisions regarding pregnancies with sex chromosome abnormalities (SCA). METHODS: Collected and reviewed records from our hospital for 1991-2005. Genetic counselling was provided by obstetricians or perinatologists. RESULT: Among 57 fetuses with SCA were 36 non-mosaic cases (four of 36, 45,X; 12 of 36, 47,XXY; seven of 36, 47,XYY, 13 of 36, 47,XXX) and 21 mosaic cases (15 of 21, 45,X mosaicism). Only 20% of 45,X mosaic pregnancies were continued, whereas all other mosaic pregnancies (100%) were continued (P = 0.004). Of 32 SCA cases counselled by a perinatologist, 66% (21 of 32) were continued. In contrast, 36% (nine of 25) of cases counselled by a general obstetrician were continued, a barely significant difference (P = 0.048). More couples chose to continue pregnancies in recent years. CONCLUSION: Genetic counselling by well-trained specialists is valuable, and the trend towards fewer terminations at our centre suggests improved parental knowledge of pathology associated with SCA.     

Analysis of the S810L point mutation of the mineralocorticoid receptor in patients with pregnancy-induced hypertension.

OBJECTIVE: A missense mutation at codon 810 (Ser --> Leu) of the mineralocorticoid receptor was recently observed in a family with early manifestation of hypertension. Our objective was to determine if this mineralocorticoid receptor alterations is prevalent in patients with pregnancy-induced hypertension. METHODS: Thirty-eight women with hypertension during pregnancy were tested for the mineralocorticoid receptor gene mutation. DNA was extracted out of blood leucocytes. PCR and automated DNA sequencing were used to analyze exon 6 for the S810L missense mutation. Anamnestical data concerning cardiovascular risk factors and family history were evaluated with a questionnaire. Pregnancy course and outcome were documented in all cases. RESULTS: In 33 patients with pregnancy-induced hypertension and in five patients with exacerbation of preexisting hypertension in pregnancy no point mutations were found at codon 810 in exon 6. CONCLUSIONS: Our data suggest that the S810L missense mutation of the mineralocorticoid receptor does not play a major role in the etiology of pregnancy-induced hypertension in a German /Turkish population.     

Clinical and hormonal features of selective follicle-stimulating hormone (FSH) deficiency due to FSH beta-subunit gene mutations in both sexes

OBJECTIVE: To report the clinical, hormonal, and molecular features of a female adolescent with selective FSH deficiency. In addition, a complete review of previous cases is provided, focusing on hormonal aspects. DESIGN: Clinical study. SETTING: University hospital. PATIENT(S): A 16-year-old girl with primary amenorrhea and poor breast development due to isolated FSH deficiency. INTERVENTION(S): Blood drawing before and after GnRH stimulation and pelvic ultrasound examination. MAIN OUTCOME MEASURE(S): Gonadotropin and E(2) measurements and sequencing of the FSH beta-subunit gene. RESULT(S): The patient was referred for primary amenorrhea and partial breast development (Tanner III). Her basal and GnRH-stimulated LH levels were elevated (31 IU/L and 98 IU/L, respectively), whereas her FSH levels were undetectable (<1 IU/L) in both conditions. Estradiol levels were low (<13 pg/mL). Automatic sequencing showed a nucleotide substitution of C for A in exon 3, resulting in a homozygous nonsense mutation in amino acid position 76 (Tyr76X) of the FSH beta-subunit. CONCLUSION(S): The Tyr76X mutation of the FSH beta-subunit was associated with a partial phenotype of FSH deficiency. To date, only four loss-of-function mutations of the FSH beta-subunit have been described in eight patients with undetectable serum FSH and high serum LH levels. Therefore, this unusual hormonal profile strongly suggests a defect in the FSH beta-subunit in both sexes.     

Linkage and mutation analysis in two Taiwanese families with long QT syndrome.

Long QT syndrome (LQT) is a cardiovascular disorder causing syncope and sudden death from arrhythmias. Mutations in KCNQ1, KCNH2, KCNE1, KCNE2, and SCN5A genes encoding cardiac potassium and sodium ion channels cause LQT. Two Taiwanese LQT families were screened for mutations in these ion channel genes. In family H87, the diagnosis was made in the 25-year-old female proband and six family members based on recurrent syncope and/or a prolonged QT interval. Genotyping revealed a novel nonsense mutation, R744X (C to T transition in codon 744), in the KCNH2 potassium channel gene, resulting in truncation of the putative cyclic nucleotide-binding domain and C-terminal region of the HERG K(+)-channel in all affected family members. The mutation was confirmed by DdeI endonuclease digestion of the DNA from each family member. The 26-year-old female proband in family L89 developed repeated syncope with QTc of 0.61 seconds. After linkage and mutation analysis, the syndrome in this family was associated with a novel KCNQ1 missense mutation, T309I, causing the substitution of a threonine residue at position 309, in the pore region of the KvLQT1 K(+)-channel, with an isoleucine. By Tsp45I restriction analysis, the mutation was noted in the proband and the proband's asymptomatic brother, but was not detected in 100 unrelated normal individuals. Identification of a mutation has clinical implications for presymptomatic diagnosis and therapy.     

Unravelling complex mosaicism of sex chromosomes in a patient with primary amenorrhea through cytogenetic analysis on urothelial cells

ObjectiveSex chromosome mosaicism remains challenging in the study of disorders of sex development (DSD). Aneuploid cells in the developing gonad play a major role in sex determination. Therefore, it is necessary acknowledge their presence by different methods. Our aim was to stand out the utility of urothelial cells for unravelling complex and hidden cell lines in DSD patients.Case reportHerein we report on a 19-year-old female with primary amenorrhea, short stature without ambiguous external genitalia. She had a 45,X/46, XY karyotype in leukocytes. Interphase FISH revealed hidden 45,X/47,XYY/47,XXY/46,XY/46, XX mosaicism in leukocytes and urothelial cells.ConclusionThese findings highlight the importance of investigating sex chromosome mosaicism in other tissues. Of particular interest in cases of DSD are the cells from the urinary epithelium, which may reflect the cell composition of the urogenital ridge, the analysis of these cells should be considered within the clinical assessment of DSD patients.     

Gene duplications in 21-hydroxylase deficiency: the importance of accurate molecular diagnosis in carrier detection and prenatal diagnosis

BACKGROUND: The detection of 21-OH deficiency (21OHD) carriers in the general population requires that misinterpretations of apparently severe mutations in alleles carrying duplicated genes be avoided. Prenatal treatment prevents virilization in female fetuses and genetic counseling may be offered to couples in which one partner is either a patient or a carrier. This paper proposes a semiquantitative PCR method involving primer extension that distinguishes the severe point mutation Q318X in single gene copy alleles from the normal/nondeficient variant in gene-duplicated alleles. SAMPLES AND METHODS: DNA from 65 individuals carrying Q318X variants, that of 85 partners of 21OHD carriers or patients, and one fetal sample (as well as the DNA of his family) were analyzed. 21OHD alleles were studied by gene-specific PCR/allele-specific oligonucleotides hybridization for common mutations, Southern analysis, complementary direct sequencing and microsatellite typing. Primer extension analysis of the Q318X variants using fluorescent dideoxynucleotides was performed on CYP21A2 gene-specific PCR-amplified DNA samples from controls, patients, potential carriers and prenatal samples. RESULTS: Different fluorescence patterns were seen for the severe mutation (single gene copy) and the nondeficient (gene-duplicated) alleles carrying Q318X. The normal/mutant fluorescence peak (N/M) ratio was < 1 in all heterozygous carriers (mean 0.83; min. 0.70; max. 0.95). In all normal individuals carrying the gene-duplicated Q318X normal variant, the N/M ratio was > 1 (mean 1.69; min. 1.44; max. 2.02). CONCLUSION: The proposed method discriminated between the severe Q318X mutation and the normal Q318X variant in gene duplication, and could be a useful complementary tool in prenatal diagnosis and carrier detection.