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Complexity in the Diagnosis and Management of 45,X Turner Syndrome Mosaicism
Pediatric Case Report Complexity in the Diagnosis and Management of 45,X Turner Syndrome Mosaicism Andrew C. Radtke, Christina Sauder, Jennifer L. Rehm, and Patrick H. McKenna Diagnosis, decision making, and counseling for patients with disorders of sexual development pose challenges for physicians and families. Accurate antenatal evaluation combined with effective communication between the family and multidisciplinary team is important to provide the best patient outcome. We reviewed 2 cases from our institution that illustrate the complexity of antenatal and postnatal management in Turner Syndrome patients who have 45,X mosaicism. We concluded that because of the complexity involved in providing appropriate care to these individuals, it is critical that accurate and universally accessible counseling materials are available to providers and families at the time of diagnosis and management decision making. UROLOGY 84: 919e921, 2014. 2014 Elsevier Inc.
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onosomy X, or Turner Syndrome (TS), is one of the most common disorders of sexual development. Patients with TS often demonstrate characteristic stigmata and physical findings: female phenotype, short stature, and delayed puberty being the most common. On a genetic level, roughly 45% of postnatal TS patients have a 45,X genotype.1 The slight majority of live births (55%) with TS have a mosaic karyotype. A patient with a mosaic karyotype carries 2 separate cell lines with different genotypes in his or her body. In TS, this means having a fraction of cells with the common TS genotype (45,X) and a second (usually smaller) fraction with a different genotype. Mosaicism in TS produces viable karyotypes that result in a wide range of sexual development outcomes with implications for sex assignment, gender identity, and fertility. In addition to these challenges, a 15%-30% risk of gonadoblastoma has been described in the literature.2 The most common secondary mosaic lines are 46,X,i(Xq); 46,XX; 47,XXX; 46,X,del(Xp); and 46,XY.1 Among these, TS with 46,XY mosaicism presents a unique challenge in perinatal management. Those patients, who have a cell line with at least a partial Y chromosome, make up 6%-12% of TS patients with mosaicism. In these cases, the Y chromosome can be either structurally normal or structurally abnormal; most frequently, it is duplicated or isodicentric. Because numerous genes on the Y chromosome regulate male sexual differentiation, the fraction of the Y chromosome, as well as the number of copies present, can cause varying Financial Disclosure: The authors declare that they have no relevant financial interests. From the Division of Pediatric Urology, Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI Reprint requests: Christina Sauder, M.S., Division of Pediatric Urology, Department of Urology, University of Wisconsin School of Medicine and Public Health, 1685 Highland Avenue, Madison, WI 53715. E-mail: [email protected] Submitted: April 28, 2014, accepted (with revisions): June 24, 2014
ª 2014 Elsevier Inc. All Rights Reserved
levels of fetal androgenization. This becomes a challenge for sexual development and gender identity because of the varying degree of virilization in these patients, which has implications for the patient’s sex of rearing, gender identity, and fertility potential. Following are 2 cases from our institution that illustrate the complexity of antenatal and postnatal management in TS patients that have 45,X mosaicism. A summary of these 2 cases can be found in Table 1.
CASE 1 This patient presented antenatally when evidence of nuchal thickening was found on screening prenatal ultrasonography. A subsequent quad screen also indicated elevated risk of genetic abnormality. Because of the mother’s history of 2 prior miscarriages, chorionic villus sampling was performed. Chorionic villus sampling revealed a 45,X karyotype, and the parents received extensive counseling regarding the implications and management of a child with TS. Labor was induced at 39 weeks. At birth, the patient was found to have ambiguous genitalia, including enlarged clitoral phallic structure, rugation of the labioscrotal folds, and partial vaginal fusion. Pelvic ultrasonography revealed a hemiuterus. The discrepancy between prenatal chorionic villus sampling and neonatal physical examination findings led to collection of a blood sample for karyotype analysis and fluorescent in situ hybridization chromosomal analysis. The analysis revealed 16 cells 45,X and 4 cells 45,X iso-Yp (Fig. 1A). The p arm of the Y chromosome, or Yp, hosts the sex determining region Y (SRY), which is required for virilization. In this case, the permutation of the Y chromosome has duplicate p arms, which includes 2 copies of the SRY gene. Although this double dose of SRY explains the patient’s virilized gonads, the ratio of mosaicism found in this analysis (from red blood cells) does not necessarily reflect that found in gonadal tissues. http://dx.doi.org/10.1016/j.urology.2014.06.030 0090-4295/14
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Table 1. Case summaries Patient 1 Examination
Genetic analysis Genotype Follow-up procedures
Patient 2
Enlarged clitoral phallic structure Rugated labioscrotal folds Partial vaginal fusion Pelvic ultrasonography: hemiuterus Karyotype, FISH 4:16 j 45,XO:45,X iso-Yp Diagnostic laparoscopy L gonadectomy: seminiferous tubules without spermatogenesis R ovarian biopsy: ovarian stroma without oogenesis
Midshaft hypospadias Chordee Separation of scrotal tissue Right undescended testis
7:23 j 45,XO:46,X,psu idic(Y)(q12) Two stage hypospadias repair Laparoscopic R gonadectomy: streak ovary L gonad biopsy: normal testicular tissue
FISH, fluorescent in situ hybridization, L, left; R, right.
Regardless, the SRY gene and resultant testosterone load created questions regarding sex of rearing and potential for fertility, even after the parents had decided to raise the child as a girl. Further genetic evaluation indicated that it was very unlikely that the portion of the Y chromosome present in the patient’s karyotype contained the azoospermia region, which contains the genes necessary for spermatogenesis (Fig. 1B). The patient followed up in our multidisciplinary disorder of sexual development clinic (pediatric urologist, pediatric geneticist, pediatric endocrinologist, and health psychologist). At 5 weeks, palpable tissue was discovered in one labioscrotal fold. It was hypothesized that this might be testicular tissue; however, this tissue was no longer present during future examinations. Based on the genetic analysis and physical findings, the patient underwent diagnostic laparoscopy with left gonadectomy and right gonadal biopsy. The left gonad was found to be a nonmalignant gonad with seminiferous tubules but without spermatogenesis. The biopsy of the right gonad was consistent with presence of a fallopian tube as well as nonmalignant normal ovarian tissue without oogenesis. Further genetic analysis showed greater percentage of SRY signal in the left gonad compared to the right ovary. Close follow-up as the child grows will be imperative as the multidisciplinary team works with the family to determine genital reconstruction, management of the remaining ovary, and sex of rearing.
CASE 2 The second patient was the result of a term pregnancy that was induced at 39 weeks. Shortly after birth, it was noted that the patient had hypospadias with the urethral tip at the midshaft, chordee, some separation of scrotal tissue, and an undescended right testis with a normal left testicle. The patient underwent hypospadias repair and release of chordae at 9 months and subsequent secondstage hypospadias repair and right laparoscopic gonadectomy at 15 months. Pathology of the undescended testis showed a streak ovary, and a biopsy of the left gonad showed infantile testicular tissue. Fluorescent in situ hybridization chromosomal analysis from erythrocytes revealed 23 cells 45,X and 7 cells 46,X,psu idic(Y)(q12) 920
Figure 1. (A) Case 1 karyotype. The analysis revealed a ratio of 16 cells 45,X to 4 cells 45,X iso-Yp. In other words, the karyotype on the left demonstrates “no” second sex chromosome (empty space in lower right corner). The karyotype on the right, on the other hand, includes the excess portion of the Y chromosome, or “iso-Yp,” which in this case, included the aberrant genetic information responsible for virilization. (B) Case 1 fluorescent in situ hybridization results. This study confirms the patient has one X-chromosome, as demonstrated by the circled area, and duplicated SRY portions of a Y chromosome as indicated by the square. Based on further analysis, it is unlikely that the portion of the Y chromosome present in the patient’s karyotype contained the azoospermia region (AZF), which contains the genes necessary for spermatogenesis. (Color version available online.)
(Fig. 2A,B). This mosaic variant contains a Y chromosome that extends beyond the centromere to q12 on the long arm. The difference in this mosaic compared to the first case, which resulted in a drastically different phenotype, was the inclusion of genetic material beyond the Y centromere—specifically, duplication of the Q arm down to Q12. Presence of the Q arm has implications for this patient’s fertility, as it contains the azoospermia UROLOGY 84 (4), 2014
Figure 2. (A) Case 2 karyotype. The analysis revealed 23 cells 45,X and 7 cells 46,X,psu idic(Y)(q12). Similar to the first case, 1 karyotype contained no second sex chromosome (left side) and the other contained duplicated Y material as a second sex chromosome (right side). The red circle denotes the chromosome of interest. (B) Case 2 fluorescent in situ hybridization (FISH) analysis results. Similar to the first case, this FISH study contained both a marker for the X chromosome (circle) and a marker for SRY (squares). The duplicated SRY is again apparent, but on closer inspection this portion of Y chromosome is longer than that in case 1. This longer fused q arm increases the probability that the isodicentric Y chromosome contains SRY genetic material. (Color version available online.)
region series of genes. An assay can be run in the future to determine whether the patient has true spermatogenic potential, but the parents have elected to forego testing at this time. The patient will continue to be raised as a male. Because one of his gonads, presumably the descended testis, was able to synthesize significant amounts of androgen during development, he should have continued potential for normal gonadal function and fertility.
COMMENT With continued advances in diagnostic technologies including genetic screening and antenatal imaging, the accuracy and availability of screening will continue to
UROLOGY 84 (4), 2014
improve; however, there remains a risk of inaccurate or insufficient counseling once these data are available. Inaccuracies in counseling may lead to an undesirable patient outcome or mismanagement of the patient’s gender assignment in more complicated or rare circumstances of a disorder of sexual development, where androgen production may impact on sex of rearing. As demonstrated in the first case, incomplete counseling may result in misdirected antenatal guidance for the family, which can cause confusion during a delicate and crucial time. Although it is easy to jump to a diagnosis of TS when a fetus demonstrates the classic findings, partially and fully virilized genitalia secondary to mosaicism are very real possibilities. Case 1 demonstrated how early antenatal counseling, even with the best intentions, can cause parents to make a mental and emotional investment in preliminary findings regarding sex of rearing. As mentioned before, early management of these patients would incorporate a multidisciplinary team, including a pediatric endocrinologist, geneticist, neonatologist, urologist, and psychologist, to help the family navigate the challenges of management and gender assignment. It is apparent that because of the complexity involved in providing appropriate care to these individuals, it is critical that accurate and universally accessible counseling materials are available to providers and families in the antenatal period when diagnosis and management decision making is first discussed. The Turner Syndrome Society of the United States is an accurate and universally available resource on the Internet that provides information on TS, current research, events, support groups, and contact information for professionals familiar with TS. For more information on the Tuner Syndrome Society of the United States visit the following website: http://www.turnersyndrome.org/#! home/mainPage. Acknowledgment. The authors acknowledge Patrick H. McKenna, M.D. for his contribution to the study.
References 1. Zhong Q, Layman LC. Genetic considerations in the patient with Turner syndrome—45,X with or without mosaicism. Fertil Steril. 2012;98:775-779. 2. Kolon TF, Gray CL, Borboroglu PG. Prenatal karyotype and ultrasound discordance in intersex conditions. Urology. 1999;54: 1097.
921
M
onosomy X, or Turner Syndrome (TS), is one of the most common disorders of sexual development. Patients with TS often demonstrate characteristic stigmata and physical findings: female phenotype, short stature, and delayed puberty being the most common. On a genetic level, roughly 45% of postnatal TS patients have a 45,X genotype.1 The slight majority of live births (55%) with TS have a mosaic karyotype. A patient with a mosaic karyotype carries 2 separate cell lines with different genotypes in his or her body. In TS, this means having a fraction of cells with the common TS genotype (45,X) and a second (usually smaller) fraction with a different genotype. Mosaicism in TS produces viable karyotypes that result in a wide range of sexual development outcomes with implications for sex assignment, gender identity, and fertility. In addition to these challenges, a 15%-30% risk of gonadoblastoma has been described in the literature.2 The most common secondary mosaic lines are 46,X,i(Xq); 46,XX; 47,XXX; 46,X,del(Xp); and 46,XY.1 Among these, TS with 46,XY mosaicism presents a unique challenge in perinatal management. Those patients, who have a cell line with at least a partial Y chromosome, make up 6%-12% of TS patients with mosaicism. In these cases, the Y chromosome can be either structurally normal or structurally abnormal; most frequently, it is duplicated or isodicentric. Because numerous genes on the Y chromosome regulate male sexual differentiation, the fraction of the Y chromosome, as well as the number of copies present, can cause varying Financial Disclosure: The authors declare that they have no relevant financial interests. From the Division of Pediatric Urology, Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI Reprint requests: Christina Sauder, M.S., Division of Pediatric Urology, Department of Urology, University of Wisconsin School of Medicine and Public Health, 1685 Highland Avenue, Madison, WI 53715. E-mail: [email protected] Submitted: April 28, 2014, accepted (with revisions): June 24, 2014
ª 2014 Elsevier Inc. All Rights Reserved
levels of fetal androgenization. This becomes a challenge for sexual development and gender identity because of the varying degree of virilization in these patients, which has implications for the patient’s sex of rearing, gender identity, and fertility potential. Following are 2 cases from our institution that illustrate the complexity of antenatal and postnatal management in TS patients that have 45,X mosaicism. A summary of these 2 cases can be found in Table 1.
CASE 1 This patient presented antenatally when evidence of nuchal thickening was found on screening prenatal ultrasonography. A subsequent quad screen also indicated elevated risk of genetic abnormality. Because of the mother’s history of 2 prior miscarriages, chorionic villus sampling was performed. Chorionic villus sampling revealed a 45,X karyotype, and the parents received extensive counseling regarding the implications and management of a child with TS. Labor was induced at 39 weeks. At birth, the patient was found to have ambiguous genitalia, including enlarged clitoral phallic structure, rugation of the labioscrotal folds, and partial vaginal fusion. Pelvic ultrasonography revealed a hemiuterus. The discrepancy between prenatal chorionic villus sampling and neonatal physical examination findings led to collection of a blood sample for karyotype analysis and fluorescent in situ hybridization chromosomal analysis. The analysis revealed 16 cells 45,X and 4 cells 45,X iso-Yp (Fig. 1A). The p arm of the Y chromosome, or Yp, hosts the sex determining region Y (SRY), which is required for virilization. In this case, the permutation of the Y chromosome has duplicate p arms, which includes 2 copies of the SRY gene. Although this double dose of SRY explains the patient’s virilized gonads, the ratio of mosaicism found in this analysis (from red blood cells) does not necessarily reflect that found in gonadal tissues. http://dx.doi.org/10.1016/j.urology.2014.06.030 0090-4295/14
919
Table 1. Case summaries Patient 1 Examination
Genetic analysis Genotype Follow-up procedures
Patient 2
Enlarged clitoral phallic structure Rugated labioscrotal folds Partial vaginal fusion Pelvic ultrasonography: hemiuterus Karyotype, FISH 4:16 j 45,XO:45,X iso-Yp Diagnostic laparoscopy L gonadectomy: seminiferous tubules without spermatogenesis R ovarian biopsy: ovarian stroma without oogenesis
Midshaft hypospadias Chordee Separation of scrotal tissue Right undescended testis
7:23 j 45,XO:46,X,psu idic(Y)(q12) Two stage hypospadias repair Laparoscopic R gonadectomy: streak ovary L gonad biopsy: normal testicular tissue
FISH, fluorescent in situ hybridization, L, left; R, right.
Regardless, the SRY gene and resultant testosterone load created questions regarding sex of rearing and potential for fertility, even after the parents had decided to raise the child as a girl. Further genetic evaluation indicated that it was very unlikely that the portion of the Y chromosome present in the patient’s karyotype contained the azoospermia region, which contains the genes necessary for spermatogenesis (Fig. 1B). The patient followed up in our multidisciplinary disorder of sexual development clinic (pediatric urologist, pediatric geneticist, pediatric endocrinologist, and health psychologist). At 5 weeks, palpable tissue was discovered in one labioscrotal fold. It was hypothesized that this might be testicular tissue; however, this tissue was no longer present during future examinations. Based on the genetic analysis and physical findings, the patient underwent diagnostic laparoscopy with left gonadectomy and right gonadal biopsy. The left gonad was found to be a nonmalignant gonad with seminiferous tubules but without spermatogenesis. The biopsy of the right gonad was consistent with presence of a fallopian tube as well as nonmalignant normal ovarian tissue without oogenesis. Further genetic analysis showed greater percentage of SRY signal in the left gonad compared to the right ovary. Close follow-up as the child grows will be imperative as the multidisciplinary team works with the family to determine genital reconstruction, management of the remaining ovary, and sex of rearing.
CASE 2 The second patient was the result of a term pregnancy that was induced at 39 weeks. Shortly after birth, it was noted that the patient had hypospadias with the urethral tip at the midshaft, chordee, some separation of scrotal tissue, and an undescended right testis with a normal left testicle. The patient underwent hypospadias repair and release of chordae at 9 months and subsequent secondstage hypospadias repair and right laparoscopic gonadectomy at 15 months. Pathology of the undescended testis showed a streak ovary, and a biopsy of the left gonad showed infantile testicular tissue. Fluorescent in situ hybridization chromosomal analysis from erythrocytes revealed 23 cells 45,X and 7 cells 46,X,psu idic(Y)(q12) 920
Figure 1. (A) Case 1 karyotype. The analysis revealed a ratio of 16 cells 45,X to 4 cells 45,X iso-Yp. In other words, the karyotype on the left demonstrates “no” second sex chromosome (empty space in lower right corner). The karyotype on the right, on the other hand, includes the excess portion of the Y chromosome, or “iso-Yp,” which in this case, included the aberrant genetic information responsible for virilization. (B) Case 1 fluorescent in situ hybridization results. This study confirms the patient has one X-chromosome, as demonstrated by the circled area, and duplicated SRY portions of a Y chromosome as indicated by the square. Based on further analysis, it is unlikely that the portion of the Y chromosome present in the patient’s karyotype contained the azoospermia region (AZF), which contains the genes necessary for spermatogenesis. (Color version available online.)
(Fig. 2A,B). This mosaic variant contains a Y chromosome that extends beyond the centromere to q12 on the long arm. The difference in this mosaic compared to the first case, which resulted in a drastically different phenotype, was the inclusion of genetic material beyond the Y centromere—specifically, duplication of the Q arm down to Q12. Presence of the Q arm has implications for this patient’s fertility, as it contains the azoospermia UROLOGY 84 (4), 2014
Figure 2. (A) Case 2 karyotype. The analysis revealed 23 cells 45,X and 7 cells 46,X,psu idic(Y)(q12). Similar to the first case, 1 karyotype contained no second sex chromosome (left side) and the other contained duplicated Y material as a second sex chromosome (right side). The red circle denotes the chromosome of interest. (B) Case 2 fluorescent in situ hybridization (FISH) analysis results. Similar to the first case, this FISH study contained both a marker for the X chromosome (circle) and a marker for SRY (squares). The duplicated SRY is again apparent, but on closer inspection this portion of Y chromosome is longer than that in case 1. This longer fused q arm increases the probability that the isodicentric Y chromosome contains SRY genetic material. (Color version available online.)
region series of genes. An assay can be run in the future to determine whether the patient has true spermatogenic potential, but the parents have elected to forego testing at this time. The patient will continue to be raised as a male. Because one of his gonads, presumably the descended testis, was able to synthesize significant amounts of androgen during development, he should have continued potential for normal gonadal function and fertility.
COMMENT With continued advances in diagnostic technologies including genetic screening and antenatal imaging, the accuracy and availability of screening will continue to
UROLOGY 84 (4), 2014
improve; however, there remains a risk of inaccurate or insufficient counseling once these data are available. Inaccuracies in counseling may lead to an undesirable patient outcome or mismanagement of the patient’s gender assignment in more complicated or rare circumstances of a disorder of sexual development, where androgen production may impact on sex of rearing. As demonstrated in the first case, incomplete counseling may result in misdirected antenatal guidance for the family, which can cause confusion during a delicate and crucial time. Although it is easy to jump to a diagnosis of TS when a fetus demonstrates the classic findings, partially and fully virilized genitalia secondary to mosaicism are very real possibilities. Case 1 demonstrated how early antenatal counseling, even with the best intentions, can cause parents to make a mental and emotional investment in preliminary findings regarding sex of rearing. As mentioned before, early management of these patients would incorporate a multidisciplinary team, including a pediatric endocrinologist, geneticist, neonatologist, urologist, and psychologist, to help the family navigate the challenges of management and gender assignment. It is apparent that because of the complexity involved in providing appropriate care to these individuals, it is critical that accurate and universally accessible counseling materials are available to providers and families in the antenatal period when diagnosis and management decision making is first discussed. The Turner Syndrome Society of the United States is an accurate and universally available resource on the Internet that provides information on TS, current research, events, support groups, and contact information for professionals familiar with TS. For more information on the Tuner Syndrome Society of the United States visit the following website: http://www.turnersyndrome.org/#! home/mainPage. Acknowledgment. The authors acknowledge Patrick H. McKenna, M.D. for his contribution to the study.
References 1. Zhong Q, Layman LC. Genetic considerations in the patient with Turner syndrome—45,X with or without mosaicism. Fertil Steril. 2012;98:775-779. 2. Kolon TF, Gray CL, Borboroglu PG. Prenatal karyotype and ultrasound discordance in intersex conditions. Urology. 1999;54: 1097.
921