Detection of Y chromosome sequences in Turner's syndrome by Southern blot analysis of amplified DNA

Gonadoblastoma in patients with Ullrich-Turner syndrome

Ullrich-Turner syndrome (UTS) is a common chromosomal abnormality caused by partial or complete X chromosome monosomy. One half of the patients have a 45,X karyotype, whereas the remaining patients display other X chromosome anomalies. In 6% to 11% of UTS, a normal or partly deleted Y chromosome has been found. A 10% to 30% risk of developing gonadoblastoma was found in the latter patients. The aim of this study was to evaluate the prevalence of Y chromosome-derived material, the occurrence of gonadoblastoma, and the incidence of possible neoplasms in patients with UTS. Of 217 patients studied with UTS and chromosome analysis of peripheral-blood lymphocytes, Y chromosome material was found in 20 patients. Fluorescence in situ hybridization (FISH) testing was performed to characterize the structurally abnormal Y chromosome in 13 cases. Molecular analysis of the SRY gene could only be performed in 20 patients with 45,X karyotype. Two patients had the SRY genomes. Of the 20 patients with Y chromosome-derived material, 17 underwent gonadectomy. The incidence of gonadoblastoma development in our series was 35.5%. Furthermore, 1 patient also showed a pure dysgerminoma, and another showed a mixed dysgerminoma and embryonal carcinoma. We emphasize the importance of complete processing of the gonadectomy specimen, including step sections, molecular studies, and FISH, in addition to the classic cytogenetic searching for Y chromosome sequences, in patients who present with a nonmosaic 45,X karyotype. Finally, we propose to routinely collect a sample for storage in the tumor bank for future studies.

Hidden Y Chromosome Mosaicism in 48 Egyptian Patients with Turner’s Syndrome

Background. The presence of Y chromosome material in Turner's syndrome (TS) patients is a risk factor for the development of gonadoblastoma. Although conventional cytogenetic analysis is the definitive diagnosis of TS, low level Y chromosome mosaicism may be missed. Molecular analysis has demonstrated a higher proportion of mosaicism, but there is controversy regarding the prevalence of Y chromosome-derived material in those patients. Aim and Methods. This study was conducted to investigate the prevalence of hidden Y chromosome mosaicism in 48 TS Egyptian patients using polymerase chain reaction (PCR) for molecular DNA analysis of SRY gene and compare our results with those in the literature. Results. None of TS patients had a cytogenetically obvious Y chromosome; Y chromosome material was detected only at molecular analysis. SRY gene was found in 9 TS patients (18.75%) with the classical 45,X karyotype, whereas all other patients were SRY negative. Conclusion. Cytogenetically undetected Y chromosome mosaicism is common in TS patients; these data reinforce the need for adequate diagnosis of Y chromosome material in those patients. Molecular screening for Y chromosome-derived DNA should be routinely carried out in all TS patients.

Genomics in pediatric endocrinology-genetic disorders and new techniques

In the last few years, there have been remarkable advances in the development of new and more sophisticated genetic techniques. These have allowed a better understanding of the molecular mechanisms of genetically determined pediatric endocrine disorders and are paving the way for a radical change in diagnosis and treatment. This article introduces some of these concepts and some of the genetic techniques being used.

Y chromosome in Turner syndrome: review of the literature

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% 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% 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%), 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.

Genomics in pediatric endocrinology--genetic disorders and new techniques

In the last few years, there have been remarkable advances in the development of new and more sophisticated genetic techniques. These have allowed a better understanding of the molecular mechanisms of genetically determined pediatric endocrine disorders and are paving the way for a radical change in diagnosis and treatment. This article introduces some of these concepts and some of the genetic techniques being used.

Genes and phenotypes of the human Y chromosome

By 1959 it was recognized that the gene (or genes) responsible for initiating the human male phenotype were carried on the Y chromosome. But in subsequent years, few phenotypes were associated with the Y chromosome. Recently, using molecular techniques combined with classical genetics, the Y chromosome has been the focus of intensive and productive investigation. Some of the findings are unexpected and have extended our understanding of the functions of the human Y chromosome. The notion that the Y chromosome is largely devoid of genes is changing. At the present, over 20 Y chromosome genes or pseudogenes have been identified or cloned, a number that is rapidly increasing. A high proportion of Y chromosome sequences have been found to be related to X chromosome sequences: the assembly of a complete physical map of the Y chromosome euchromatic region (believed to carry all of the genes) has shown 25% of the region studied to have homology to the X chromosome.3 Several X-homologous genes are located in the X and Y chromosome pairing regions, an area predicted to have shared homology. Surprisingly, some of the Y-encoded genes that lie outside of the X and Y pairing region share high sequence similarity, and in at least one case, functional identity, with genes on the X chromosome.

Molecular identification of chromosome Y sequences in Brazilian patients with Turner syndrome

The investigation of Y-specific sequences in patients with Turner Syndrome (TS) with karyotype 45,X or mosaic, has a fundamental role in the clinical management of these patients. The relationship between the presence of Y chromosome fragments and a higher risk of gonadoblastoma in TS has already been established. The aim of the study was to investigate the presence of Y-chromosome fragments in a population of 42 female Brazilian patients with TS from Mato Grosso state. Cytogenetic analysis has shown the karyotypes 45,X in 27 of them (64.3%) and mosaic in 15 (35.7%). The presence of the Y-primers SRY, DYZ3, ZFY, DYZ1, DYS1 and PABY was investigated in all patients. These markers were amplified by polymerase chain reaction (PCR) technique, using DNA genomic from peripheral blood lymphocytes. None of these patients had shown any Y-chromosome fragments when they were analysed only by the classic cytogenetic technique. The PCR analysis with the Y-specific sequences ZFY and DYZ3 were identified in two different patients (4.8%), both with karyotype 45,X. It was concluded that PCR is efficient in the investigation of hidden Y-fragments in TS patients. Therefore, this method should be included in the routine assistance of these patients.

Clinical implications of the detection of Y-chromosome mosaicism in Turner's syndrome: report of 3 cases

OBJECTIVE

To determine the clinical implications of the presence of a Y chromosome in Turner's syndrome patients with karyotype abnormalities.

DESIGN

To investigate the presence of Y-chromosome sequences in different tissue samples.

SETTING

Endocrinology outpatient clinic of a federal university in Brazil.

PATIENT(S)

Five Turner's syndrome patients with karyotype abnormalities such as marker chromosomes, additional material, or ring chromosomes.

INTERVENTION(S)

Peripheral blood, oral epithelial cells, and hair root samples were collected.

MAIN OUTCOME MEASURE(S)

The SRY gene and the DYZ3 repeat region were amplified by polymerase chain reaction followed by gel electrophoresis mobility of amplified genomic DNA, and ultraviolet visualization. Prophylactic gonadectomy was offered to the Y-positive patients.

RESULT(S)

The analysis of the different tissues revealed that three of the five patients studied presented Y-chromosome mosaicism. These three patients underwent prophylactic gonadectomy, and in one of them, the histopathologic study of the gonads disclosed hilus cell hyperplasia and stromal luteoma with contralateral nodular hyperthecosis.

CONCLUSION(S)

A systematic search for Y-chromosome mosaicism in Turner's syndrome patients is justified by the risk of developing gonadal tumors or androgen-producing lesions.

Y chromosome mosaicism and occurrence of gonadoblastoma in cases of Turner syndrome and amenorrhoea

In the present study, 73 cases with a clinical diagnosis of Turner syndrome, or with primary or secondary amenorrhoea without frank Turner phenotype, were evaluated for presence of low level Y chromosome mosaicism using molecular methods. Fluorescence in-situ hybridization for centromere and q arm of the Y chromosome and nested polymerase chain reaction for the sex determining region on Y (SRY) gene were performed in peripheral blood, buccal cells and gonadal biopsies. The overall frequency of Y chromosome mosaicism was found to be 18% (13/73 cases). Four cases (16%) of Turner syndrome had Y chromosome mosaicism, seven cases (28%) with primary amenorrhoea and two cases (9%) with secondary amenorrhoea had Y chromosome mosaicism. Histologically detectable gonadoblastoma was observed in one of seven cases (14%) that had Y chromosome mosaicism. This frequency is lower than that reported previously, underscoring the need for large prospective investigations to determine the frequency of Y chromosome mosaicism and occurrence of gonadoblastoma in cases of Turner syndrome and other forms of amenorrhoea.

Detection of Y chromosomal material in patients with a 45,X karyotype by PCR method

A 45,X karyotype is one of the common chromosomal abnormalities characterized by short stature, lack of development of secondary sexual characteristics, webbed neck and cubitus valgus. This phenotype was described by Turner in 1938 and was called Turner syndrome (TS). About 40-60% of the patients with TS phenotype have a 45,X karyotype, the rest either have a structurally abnormal X or Y chromosome or mosaicism with a second cell line. Determination of Y chromosome derivatives in patients with a 45,X karyotype is important for the management of these patients due to increased risk of gonadoblastoma. Low level mosaicism of Y chromosome may be missed by cytogenetic methods. The aim of our study is to analyze cryptic Y chromosome derivatives using Y specific sequences in 40 Turkish patients with a pure 45,X karyotype. Fourteen different Y specific sequences along the Y chromosome were selected for the detection of cryptic Y chromosome material by PCR analysis. The present study demonstrated that 2 patients with a 45,X karyotype (5%) have Y specific sequences except sex related region Y (SRY). One of them had displayed enhanced virilisation whereas other showed no virilisation. In conclusion, it has been found by PCR analysis that 5% of patients with a 45,X karyotype have Y chromosome sequences in the absence of any marker chromosome by cytogenetic analysis. The data also suggest that the patients with a 45,X karyotype should be analyzed for the presence of Y chromosome derivatives by sensitive methods, such as PCR, in order to calculate the future risk of developing gonadoblastoma.

Detection of hidden Y mosaicism in Turner's syndrome: importance in the prevention of gonadoblastoma

The presence of Y chromosome fragments in patients with Turner's syndrome (TS) is known to increase the risk of gonadoblastoma. The investigation of Y sequences is usually performed only in the presence of marker chromosomes and therefore does not rule out the presence of hidden mosaicism in patients with 45,X TS without any marker.

AIMS

1. To investigate the presence of hidden Y mosaicism in non-mosaic 45,X patients with TS, using samples from different tissues, and its association with the development of gonadoblastoma.

STUDY DESIGN

Twenty patients with a 45,X karyotype were studied. The SRY and DYZ3 sequences were amplified by PCR, using genomic DNA from peripheral blood, oral epithelial cells and hair roots. Prophylactic gonadectomy was offered to the Y-positive patients.

RESULTS

The analysis of the different tissues revealed that seven (35%) out of the 20 patients studied presented hidden chromosome Y mosaicism. Four of these patients underwent prophylactic gonadectomy, and bilateral gonadoblastoma was found in one of them.

CONCLUSIONS

A systematic search for hidden Y chromosome mosaicism in patients with TS and 45,X karyotype is justified by the possibility of developing gonadoblastoma.

Germ cell tumors in the intersex gonad: old paths, new directions, moving frontiers

The risk for the development of germ cell tumors is an important factor to deal with in the management of patients with disorders of sex development (DSD). However, this risk is often hard to predict. Recently, major progress has been made in identifying gene-products related to germ cell tumor development (testis-specific protein-Y encoded and octamer binding transcription factor 3/4) and in recognizing early changes of germ cells (maturation delay, preneoplastic lesions, and in situ neoplasia). The newly recognized "undifferentiated gonadal tissue" has been identified as a gonadal differentiation pattern bearing a high risk for the development of gonadoblastoma. It is expected that the combination of these findings will allow for estimation of the risk for tumor development in the individual patient (high risk/intermediate risk/low risk). This article reviews the recent literature regarding the prevalence of germ cell tumors in patients with DSD. Some major limitations regarding this topic, including a confusing terminology referring to the different forms of intersex disorders and unclear criteria for the diagnosis of malignant germ cells at an early age (maturation delay vs. early steps in malignant transformation) are discussed. Thereafter, an overview of the recent advances that have been made in our knowledge of germ cell tumor development and the correct diagnosis of early neoplastic lesions in this patient population is provided. A new classification system for patients with DSD is proposed as a tool to refine our insight in the prevalence of germ cell tumors in specific diagnostic groups.

Gonadoblastoma in Turner syndrome and Y-chromosome-derived material

The identification of Y-chromosome material is important in females with Ullrich-Turner syndrome (UTS) due to the risk of developing gonadoblastoma or other gonadal tumors. There is controversy regarding the frequency of the Y-chromosome-derived material and the occurrence of gonadoblastoma in these patients. The aim of our study was to evaluate a large number of patients with UTS, followed before and during the pubertal age for the prevalence of Y-chromosome derived material, the occurrence of gonadoblastoma, and the incidence of possible neoplastic degeneration. An unselected series of 171 patients with UTS (1-34 years old), diagnosed cytogenetically, was studied for Y-chromosome markers (SRY and Y-centromeric DYZ3 repeats). The follow-up was of 2-22 years; 101 of these patients were followed during pubertal age. Y-chromosome material was found in 14 patients (8%): 12 of these were gonadectomized (2.8-25.9 years). A gonadoblastoma was detected in four patients under 16 years of age: in two, Y-material was detected only at molecular analysis (at conventional cytogenetic analysis, one was included in the 45,X group and one in the X + mar group) and one had also an immature teratoma and an endodermal sinus carcinoma. The prevalence of gonadoblastoma in our series of gonadectomized UTS patients with Y-positive material was of 33.3% (4/12). Our data suggest that the age of appearance and the possibility of malignant degeneration of gonadoblastoma can occur early in life. These patients, in particular those with 45,X or a marker chromosome may benefit from molecular screening to detect the presence of Y-chromosome material; PCR is a rapid and inexpensive technique. At the moment, laparoscopy and preventive gonadectomy performed as soon as possible remain the procedures of choice for patients with UTS, when Y-chromosome has been identified, as we are still unable to predict a future malignant evolution of gonadoblastoma.

Gonadoblastoma in Turner syndrome patients with nonmosaic 45,X karyotype and Y chromosome sequences

Turner syndrome (TS) is a disorder caused by partial or complete X-chromosome monosomy. Studies in TS patients with different karyotypes have demonstrated the presence of Y-chromosome-derived sequences (4-61%). Early detection of Y-chromosome sequences in TS is of great importance because of the high risk of gonadal tumor development. We investigated the presence of Y-chromosome sequences in TS patients with a 45,X karyotype. One hundred seven unrelated 45,X Mexican TS patients recruited between 1992 and 2003 were included. Y-chromosome-derived sequences were found by polymerase chain reaction in 10 (9.3%) patients. Six subjects underwent gonadectomy and in one of them a gonadoblastoma was found; another developed a gonadoblastoma with dysgerminoma. Because of the high proportion (33%) of gonadal tumors in patients with Y-chromosome sequences found among our patients of mestizo origin, adequate counseling regarding a gonadectomy should be given.

Y chromosome sequences in Turner's syndrome: association with virilization and gonadoblastoma

The presence of Y chromosome fragments in patients with Turner's syndrome is known to increase the risk of gonadoblastoma and virilization. Y chromosome material is detected in up to 6% of patients with Turner's syndrome by karyotype. By DNA analysis, Y chromosome sequences have been reported in 0-60% of patients. The putative gonadoblastoma gene has been mapped to the pericentromeric region of the Y chromosome increasing the interest in studying these sequences.

AIMS

1. To determine the frequency of occult Y chromosome sequences in patients with Turner's syndrome. 2. To analyze the clinical implications of Y sequences detected by karyotype and occult Y sequences.

STUDY DESIGN

Cross-sectional study of 58 patients with Turner's syndrome (30 45,X; two with structural anomalies; 26 mosaic [two of whom were 45,X/46,XY]). SRY, TSPY and DYZ3 sequences were amplified by PCR using genomic DNA from peripheral blood.

RESULTS

All three Y chromosome sequences were found in one out of 56 patients whose karyotype was not suggestive of having Y chromosome material and in one patient with 45,X/46,Xr(X) karyotype. The patients with the ring chromosome and 45,X/46,XY karyotype underwent surgery and were found to have a gonadoblastoma and dysgerminoma. The four patients with Y chromosome material had non-virilized female genitalia.

CONCLUSIONS

Analysis by PCR was more sensitive in detecting Y chromosome sequences than conventional karyotype. The presence of Y material was not associated with virilization. We confirmed the association of Y fragments and gonadoblastoma at an early age.

Post-transplant Kaposi sarcoma originates from the seeding of donor-derived progenitors

Kaposi sarcoma (KS) is a vascular tumor that can develop in recipients of solid tissue transplants as a result of either primary infection or reactivation of a gammaherpesvirus, the KS- associated herpesvirus, also known as human herpesvirus-8 (HHV-8). We studied whether HHV-8 and the elusive KS progenitor cells could be transmitted from the donor through the grafts. We used a variety of molecular, cytogenetic, immunohistochemical and immunofluorescence methods to show that the HHV-8-infected neoplastic cells in post-transplant KS from five of eight renal transplant patients harbored either genetic or antigenic markers of their matched donors. These data suggest the use of donor-derived HHV-8-specific T cells for the control of post-transplant KS.

Detection of Y-specific sequences in 122 patients with Turner syndrome: nested PCR is not a reliable method

The incidence of Y chromosome sequences in patients with Turner syndrome has been evaluated in several studies, and its frequency varied from 0% to 61%, depending on the molecular methodology used. The aim of our study was to screen for Y chromosome sequences in 122 patients with Turner syndrome without cytogenetic evidence of this chromosome. DNA of 100 normal women was also screened and it was used as a negative control. To identify cryptic Y mosaicism, eight regions of Y chromosome were amplified by PCR. In order to increase the sensitivity of Y sequence detection, a nested PCR of the SRY and TSPY genes was also performed. All patients had several stigmata of Turner syndrome and none of them presented with signs of virilization. The most frequent karyotype was 45,X (54.1%), followed by mosaicism involving structural aberration of the X chromosome. There were 12 patients who carried a marker or ring chromosome. First-round PCR identified Y chromosome sequences in only four patients (3%), and all of them had a chromosome mosaicism with at least one cell lineage with a marker chromosome. After nested PCR, 25% of the patients and 14% of the normal women were positive for the presence of Y sequences. Contamination with extraneous genomic DNA was ruled out by microsatellite studies, but we cannot eliminate the possibility of contamination with PCR products, despite careful handling. We conclude that nested PCR overestimated the frequency of Y sequences in patients with Turner syndrome and should be avoided to prevent false positive results, which lead to unnecessary surgical treatment of these patients.

Genetic analysis of mosaicism in 53 women with Turner syndrome

Mosaicism involving the sex chromosomes is a common finding in women with Turner syndrome (TS). It is especially important to detect Y-chromosomal material, since this is a risk factor for the development of gonadoblastoma. Recent studies have also indicated that the frequency of 45,X cells may be used to predict prognosis. As part of an ongoing multi-disciplinary study, we have examined the extent of Y-chromosomal material and sex chromosomal mosaicism and its tissue specificity in 53 women with TS. The results of lymphocyte karyotyping were compared with the use of interphase X/Y fluorescence in situ hybridisation (FISH) analysis of lymphocytes and buccal mucosal cells. As could be expected, an extended FISH analysis detected more Y-chromosomal material than karyotyping (in 15% vs. 11% of the women, respectively) and also detected more X-chromosomal mosaicism among the TS women (in 70% vs. 45 % of the women, respectively). In half of the women, tissue-specific differences between lymphocytes and buccal mucosal cells were found. Based on these results, we suggest the use of X/Y interphase FISH as a complement to karyotyping in order to obtain a more complete knowledge of the chromosome constitution of each individual with TS.

Occurrence of gonadoblastoma in females with Turner syndrome and Y chromosome material: a population study

The presence of Y chromosome material in patients with Turner syndrome is a risk factor for the development of gonadoblastoma. However, no cases with gonadoblastoma or other ovarian malignancies have been found in epidemiological studies of cancer, morbidity, or mortality in Turner syndrome. We examined 114 females with Turner syndrome for the presence of Y chromosome material by PCR. Initially, five different primer sets were used. Y Chromosome-positive individuals were further examined with an additional four primer sets. We found 14 (12.2%; 95% confidence interval, 6.9-19.7%) patients who had Y chromosome material. The karyotype in 7 of these patients did not suggest the presence of Y chromosome material. Seven of the patients had been ovariectomized before entering the study due to verified Y chromosome material, whereas three patients were operated upon after the DNA analysis. The histopathological evaluations showed that 1 of the 10 ovariectomized patients actually had a gonadoblastoma. The rest of the patients did not have gonadoblastoma or carcinoma in situ on histopathological evaluation. Three patients (age, >50 yr) positive for Y chromosome material chose not to have ovariectomy performed, and detailed ultrasonographies did not suggest the presence of gonadoblastoma. The frequency of Y chromosome material is high in Turner syndrome (12.2%), but the occurrence of gonadoblastoma among Y-positive patients seems to be low (7-10%), and the risk may have been overestimated in previous studies, perhaps due to problems with selection bias. This study emphasizes the need for prospective unbiased studies.

Ullrich-Turner syndrome: relevance of searching for Y chromosome fragments

Forty consecutive patients with Ullrich-Turner syndrome (UTS) were followed-up and investigated for the presence of Y chromosome fragments in their genomes. We used the polymerase chain reaction (PCR) to detect SRY (sex-determining region on the Y chromosome) and the sequence-tagged sites (STS) sY57, sY59, sY85, sY94, sY124 and sY157--which correspond to regions 3C (sY57 and 59), 5C, 5G, 5P, and 6F, respectively, of the Y chromosome--searching for Y fragments that could bear the putative locus (loci) for gonadoblastoma (GBY). It has been shown that the presence of GBY greatly increases the risk of dysgenic gonads to undergo malignant transformation. Among our 40 patients, we found Y-derived sequences--including SRY and the region spanning from sY57 to sY94--in two. These two patients had a marker chromosome detected by conventional cytogenetic analysis (45,X/46,X + mar). Their gonads were excised and found to be streaks. In one of the patients, we found foci of primitive sex cords (amidst the gonadal stroma), oviducts and Wolffian remnants. Fluorescence in situ hybridization (FISH) did not show Y chromosome material in her gonad-derived fibroblasts. The other girl had hyperplastic Leydig cells in the gonadal stroma, oviducts and Wolffian remnants, with signs of epididymal differentiation. PCR assays performed on DNA extracted from paraffin-embedded gonadal tissue were negative for SRY sequences in both patients. These findings show that all UTS patients should be examined for Y chromosome material, and that positive cases should have their dysgenic gonads excised due to the high risk of malignancy.

Y-chromosome identification by PCR and gonadal histopathology in Turner's syndrome without overt Y-mosaicism

OBJECTIVE

The frequency of gonadoblastoma is high in patients with Turner's syndrome bearing cells with Y or partial Y-chromosome. About 60% of patients with Turner's syndrome have a 45,X karyotype. In 30% of them a Y-sequence is disclosed by DNA analysis. To identify patients at risk of developing gonadoblastoma, a PCR based assay with SRY, ZFY and DYZ3 specific primers was carried out to detect different Y-sequences in the DNA of peripheral lymphocytes from patients with Turner's syndrome.

DESIGN AND PATIENTS

Peripheral blood karyotypes from 36 patients with Turner's syndrome were studied. Patients with proven Y-chromosomal material were excluded. Genomic DNA was extracted from peripheral blood. SRY and ZFY genes and DYZ3 repetion of Y-chromosome were amplified by PCR. Patients with clinical signs of hyperandrogenism or with positive Y-sequences by PCR underwent gonadectomy. The gonadal tissues were examined for Y-sequences using PCR, morphology and immunohistochemical study.

MEASUREMENTS

Turner's syndrome and signs of hyperandrogenism were evaluated both clinically and through laboratory tests. Haematoxylin and eosin staining was employed in gonadal morphology studies. The presence of testosterone was detected by immunohistochemistry using a monoclonal antibody.

RESULTS

Two patients who had Y-positive blood samples and three hyperandrogenic (2 hirsutes, 1 virilized) Y-negatives underwent gonadectomy. PCR was carried out on their gonadal tissue. The tissue from the two patients without hyperandrogenism was Y-positive. The gonadal tissue from the three hyperandrogenics was Y-negative. Gonadal morphology disclosed hilus cell hyperplasia in the 3 hyperandrogenic Y-negatives and in one Y-positive patient; stromal luteoma and hyperthecosis in the virilized patient, cystadenofibroma in one hirsute patient and gonadoblastoma in one Y-positive. Testosterone was detected immunohistochemically in the hilus cell hyperplasia, stromal luteoma and hyperthecosis found in the hyperandrogenic patients.

CONCLUSIONS

The molecular study was sensitive and useful in the evaluation of patients at risk of developing gonadoblastoma. Other nontumour, gonadotrophin-dependent and Y-independent mechanisms which deserve the same medical approach may be involved in the genesis of hyperandrogenic signs in Turner's syndrome.

Detection and incidence of cryptic Y chromosome sequences in Turner syndrome patients

The presence of Y chromosome sequences in Turner syndrome (TS) patients may predispose them to gonadoblastoma formation with an estimated risk of 15-25%. The aim of this study was to determine the presence and the incidence of cryptic Y chromosome material in the genome of TS patients. The methodology involved a combination of polymerase chain reaction (PCR) and nested PCR followed by Southern blot analysis of three genes the sex determining region Y (SRY), testis specific protein Y encoded (TSPY) and RNA binding motif protein (RBM) (previously designated as YRRM) and nine additional STSs spanning all seven intervals of the Y chromosome. The methodology has a high sensitivity as it detects one 46,XY cell among 10(5) 46,XX cells. Reliability was ensured by taking several precautions to avoid false positive results. We report the results of screening 50 TS patients and the identification of cryptic Y chromosome material in 12 (24%) of them. Karyotypes were divided in four groups: 5 (23.8%) patients out of the 21 TS patients which have the 45,X karyotype (group A) also have cryptic Y sequences; none (0%) of the 7 patients who have karyotypes with anomalies on one of the X chromosomes have Y mosaicism (group B); 1 (6.3%) of the 16 patients with a mosaic karyotype have Y material (group C); and 6 (100%) out of 6 patients with a supernumerary marker chromosome (SMC) have Y chromosome sequences (group D). Nine of the 12 patients positive for cryptic Y material were recalled for a repeat study. Following new DNA extraction, molecular analysis was repeated and, in conjunction with fluorescent in situ hybridization (FISH) analysis using the Y centromeric specific probe Yc-2, confirmed the initial positive DNA findings. This study used a reliable and sensitive methodology to identify the presence of Y chromosome material in TS patients thus providing not only a better estimate of a patient's risk in developing either gonadoblastoma or another form of gonadal tumor but also the overall incidence of cryptic Y mosaicism.

Frequency of Y chromosomal material in Mexican patients with Ullrich-Turner syndrome

Cytogenetic studies have shown that 40-60% of patients with Ullrich-Turner syndrome (UTS) are 45,X, whereas the rest have structural aberrations of the X chromosome or mosaicism with a second cell line containing a structurally normal or abnormal X or Y chromosome. However, molecular analysis has demonstrated a higher proportion of mosaicism, and studies in different populations have shown an extremely variable frequency of Y mosaicism of 0-61%. We used Southern blot analysis and polymerase chain reaction (PCR) to detect the presence of Ycen, ZFY, SRY, and Yqh in 50 Mexican patients with UTS and different karyotypes to determine the origin of marker chromosomes and the presence of Y sequences. Our results indicated the origin of the marker chromosome in 1 patient and detected the presence of Y sequences in 4 45,X patients. Taken together, we found a 12% incidence of Y sequences in individuals with UTS. The amount of Y-derived material was variable, making the correlation between phenotype and molecular data difficult. Only 1 patient had a gonadoblastoma. We discuss the presence of Y chromosomes or Y sequences in patients with UTS and compare our frequency with that previously reported.

Morbidity in Turner syndrome

Turner syndrome afflicts approximately 50 per 100,000 females and is characterized by retarded growth, gonadal dysgenesis, and infertility. Much attention has been focused on growth and growth promoting therapies, while less is known about the natural course of the syndrome, especially in adulthood. We undertook this study to assess the incidence of diseases relevant in the study of Turner syndrome. The study period was from January 1, 1984 to December 31, 1993, and the study base was all women living in Denmark during the study period. We used data from the Danish Cytogenetic Central Register and the Danish National Registry of Patients to assess morbidity. This study supports several earlier studies reporting increased morbidity and confirms results of a recent study on cancer in Turner syndrome. Women with Turner syndrome seem to have an increased incidence of fractures, osteoporotic fractures in adulthood, and non-osteoporotic fractures in childhood. Furthermore, diabetes mellitus, both NIDDM and IDDM, was found with a markedly increased incidence in Turner syndrome, as well as ischemic heart disease, hypertension, and stroke. The risk of cancer, except cancer of the large bowel, does not seem to be elevated in Turner syndrome. Our data suggest that patients with Turner syndrome are extraordinarily prone to abnormalities constituting the metabolic syndrome (e.g., hypertension, dyslipidaemia, NIDDM, obesity, hyperinsulinemia and hyperuricemia). The present data may help to explain the decreased life span found in patients with Turner syndrome.

Occurrence of cancer in women with Turner syndrome

A study of cancer incidence in a cohort of 597 women with Turner syndrome (TS) and a virtually complete follow-up is presented. The cohort was established from the Danish Cytogenetic Register. Information on cancer incidence was obtained from the Danish Cancer Registry and compared with the expected number calculated from the age-, period- and site-specific cancer rates for Danish women. A total of 21 neoplasms was observed, of which 13 occurred more than 1 year after diagnosis of TS, corresponding to a relative risk of cancer of 1.1. Wilms' tumour was the only identified childhood cancer. No case of gonadoblastoma or dysgerminoma was identified in the 29 women with a Y chromosome or in the women in whom no Y chromosome material was detected by standard cytogenetic methods, suggesting that the risk of ovarian germ cell tumours may be lower than previously estimated. Colon cancer was observed in five patients (relative risk 6.9, 95% confidence interval 2.2-16.2). Further studies are needed to assess whether colon cancer in TS is related to Turner-associated genes on the sex chromosome(s).

PCR-based study of the presence of Y-chromosome sequences in patients with Ullrich-Turner syndrome

The presence of Y chromosome sequences in Ullrich-Turner syndrome (UTS) patients has been suggested in previous work. Karyotype analysis estimated at about 60% of patients with a 45, X constitution and molecular analysis (Southern blot analysis with several Y chromosome probes and PCR of specific sequences) identified the presence of Y chromosome material in about 40% of 45, X patients. We have developed a very sensitive, PCR-based method to detect Y specific sequences in DNA from UTS patients. This protocol permits the detection of a single cell carrying a Y sequence among 10(5) Y-negative cells. We studied 18 UTS patients with 4 Y-specific sequences. In 11 patients we detected a positive amplification for at least one Y sequence. The existence of a simple and sensitive method for the detection of Y sequences has important implications for UTS patients, in view of the risk for some of the females carrying Y-chromosome material of developing gonadoblastoma and virilization. Additionally, some of the UTS associated phenotypes, such as renal anomalies, could be correlated with the presence of Y chromosome specific sequences.

Parental origin of the X chromosome, X chromosome mosaicism and screening for "hidden" Y chromosome in 45,X Turner syndrome ascertained cytogenetically

Our study confirms the finding that about 85% of X chromosomes in Turner girls are maternally derived. A new observation is the detection of a high frequency of mosaicism (15%) in Turner girls who by cytogenetic analysis were thought to have a pure 45,X karyotype. DNA examination of the material was done by hybridization with digoxigenin labelled, non-radioactive probes, and PCR products for microsatellite analysis were run on polyacrylamide gels. We screened for the presence of "hidden" Y chromosome mosaicism, using the primers SRY, ZFY, DYZ3, DYZ1 and DYS132. Contrary to other reports using the PCR technique to unravel "hidden" Y chromosome mosaics, we did not find any positive cases. A precise technical protocol for these new techniques is given, and the advantages are discussed.

Detection of Y chromosome sequences in a 45,X/46,XXq--patient by Southern blot analysis of PCR-amplified DNA and fluorescent in situ hybridization (FISH)

In some cases of gonadal dysgenesis, cytogenetic analysis seems to be discordant with the phenotype of the patients. We have applied techniques such as Southern blot analysis and fluorescent in situ hybridization (FISH) to resolve the phenotype/genotype discrepancy in a patient with ambiguous genitalia in whom the peripheral blood karyotype was 45,X. Gonadectomy at age 7 months showed the gonadal tissue to be prepubertal testis on the left side and a streak gonad on the right. The karyotype obtained from the left gonad was 45,X/46,XXq- and that from the right gonad was 45,X. Three different techniques, PCR amplification, FISH, and chromosome painting for X and Y chromosomes, confirmed the presence of Y chromosome sequences. Five different tissues were evaluated. The highest percentage of Y chromosome positive cells were detected in the left gonad, followed by the peripheral blood lymphocytes, skin fibroblasts, and buccal mucosa. No Y chromosomal material could be identified in the right gonad. Since the Xq- chromosome is present in the left gonad (testis), it is likely that the Xq- contains Y chromosomal material. Sophisticated analysis in this patient showed that she has at least 2 cell lines, one of which contains Y chromosomal material. These techniques elucidated the molecular basis of the genital ambiguity for this patient. When Y chromosome sequences are present in patients with Ullrich-Turner syndrome or gonadal dysgenesis, the risk for gonadal malignancy is significantly increased. Hence, molecular diagnostic methods to ascertain for the presence of Y chromosome sequences may expedite the evaluation of patients with ambiguous genitalia.

Y Chromosomal Sequences Identified in Gonadal Tissue of Two 45,X Patients with Turner Syndrome

We examined excised gonadal tissue obtained from two 45,X patients for evidence of Y chromosomal material. Both patients had features atypical for individuals with Turner syndrome, a large dysgerminoma in patient 1 and clitoromegaly in patient 2. Southern blot analysis of polymerase chain reaction (PCR)-amplified DNA was performed for five Y chromosome-specific probes (SRY, ZFY. DYZ3, KALY, and DYZ1). Fluorescence in situ hybridization (FISH) with a combination probe specific for the DYZ1/DYZ3 loci was utilized. For both patients, Southern blot analysis of PCR-amplified DNA with primers for the SRY gene was positive. No signals were detected with the other Y chromosome-specific probes for patient 1. For patient 2, positive signals were obtained for all-Y-specific probes. FISH was negative in the gonadal specimen from patient 1, while rare cells were positive in the sections from patient 2. Turner syndrome and mixed gonadal dysgenesis may represent different points on a continuum of disorders of sexual differentiation. Although the risk for gonadal tumors is considered to be low in patients with Turner syndrome, prospective evaluation is critical to ascertain: The frequency of somatic cell mosaicism for cell lines carrying Y chromosomal material, and how the presence of Y chromosomal material in patients with Turner syndrome affects the propensity for virilization and gonadal neoplasms.

Bone marrow augmentation of donor-cell chimerism in kidney, liver, heart, and pancreas islet transplantation

We have previously postulated that donor cell chimerism in organ transplantation is needed to attain a tolerant state. Here we show that donor cell chimerism can be augmented in organ recipients if they are infused perioperatively with 3 x 10(8) per kg of unmodified donor bone marrow cells and are kept on a conventional immunosuppressive regimen of tacrolimus (FK506) and prednisolone. 36 patients took part, of whom the first 18 patients have good transplanted kidney (n = 10), liver (n = 7), and heart (n = 7) function when followed up between 4 and 16 months. All patients are well. We found persistent multilineage leucocyte chimerism in blood of 17 recipients by flow cytometry and PCR techniques to detect donor alleles or Y chromosomes in female recipients of male organs. The use of the 5-antigben HLA matched same sex donor precluded detection of chimerism in one patient.