Incidence, prevalence, age at diagnosis, and mortality in individuals with 45,X/46,XY mosaicism: A population-based registry study

PURPOSE

To assess the population-based incidence, prevalence, and age at diagnosis of individuals with 45,X/46,XY mosaicism (and associated variants) and describe the associated mortality pattern. In addition, a systematic literature review of papers providing prevalence data of 45,X/46,XY mosaicism was performed.

METHODS

A population-based epidemiological study of all individuals diagnosed with 45,X/46,XY mosaicism between 1960 and 2019. Mortality was analyzed using data from the Danish Causes of Death Register. One-hundred randomly age- and sex-matched general population controls per case were identified for comparison.

RESULTS

One-hundred-thirty-seven males and 46 females with 45,X/46,XY mosaicism were identified. The apparent prevalence was 5.6 per 100,000 liveborn males and 2.1 per 100,000 liveborn females. The incidence of males with 45,X/46,XY increased during the study (P > .0001) but was stable for females (P = .4). Males were significantly older than females when diagnosed (median age = 29.1, interquartile range: 3.4-41.3) years versus 13.3 (interquartile range: 2.1-19.1) years, P = .002). All-cause mortality was doubled in males with 45,X/46,XY (Hazard Ratio = 2.0, 95% confidence interval: 1.2-3.3) and quadrupled in females (Hazard Ratio = 4.0, confidence interval: 2.0-7.9).

CONCLUSION

The apparent population-based prevalence of males and females with 45,X/46,XY is 5.6 and 2.1 per 100,000 liveborn males and females, respectively. Diagnosis of males with 45,X/46,XY males is increasing. 45,X/46,XY mosaicism is associated with an increased all-cause mortality.

Complete or partial loss of the Y chromosome in an unselected cohort of 865 non-vasectomized, azoospermic men

BACKGROUND

Structural abnormalities as well as minor variations of the Y chromosome may cause disorders of sex differentiation or, more frequently, azoospermia. This study aimed to determine the prevalence of loss of Y chromosome material within the spectrum ranging from small microdeletions in the azoospermia factor region (AZF) to complete loss of the Y chromosome in azoospermic men.

RESULTS

Eleven of 865 azoospermic men (1.3%) collected from 1997 to 2022 were found to have a karyotype including a 45,X cell line. Two had a pure 45,X karyotype and nine had a 45,X/46,XY mosaic karyotype. The AZF region, or part of it, was deleted in eight of the nine men with a structural abnormal Y-chromosome. Seven men had a karyotype with a structural abnormal Y chromosome in a non-mosaic form. In addition, Y chromosome microdeletions were found in 34 men with a structural normal Y chromosome. No congenital malformations were detected by echocardiography and ultrasonography of the kidneys of the 11 men with a 45,X mosaic or non-mosaic cell line.

CONCLUSIONS

In men with azoospermia, Y chromosome loss ranging from small microdeletions to complete loss of the Y chromosome was found in 6.1% (53/865). Partial AZFb microdeletions may give a milder testicular phenotype compared to complete AZFb microdeletions.

Clinical and hormonal characteristics and growth data of 45,X/46,XY mosaicism in 38 Chinese patients

Backgrounds

45,X/46,XY mosaicism is the most common type of sex chromosomal abnormality in disorders of sex development (DSD). We investigated the clinical manifestations, serum sex hormone levels and growth data of 38 45,X/46,XY mosaicism patients, which provides better insight into this disease.

Methods

We prospectively evaluated 38 patients who were diagnosed with 45,X/46,XY mosaicism at the Department of Endocrinology of Shanghai Children's Hospital from 2010 to 2020. We analyzed clinical data from the patients, including hormone levels, height, weight, body mass index (BMI) and gonadal pathology results.

Results

Among the 38 cases of 45,X/46,XY mosaicism, 18 cases showed a female external genitalia phenotype (the female group) with an external masculinization score (EMS) of 1 (0-3) [median (range)], and 20 cases showed a male external genitalia phenotype (the male group) with an EMS of 7.63 (3-11) [median (range)]. The age at diagnosis ranged from 0.7 to 16.1 years. Under 2 years of age, the standard deviation scores of height (HtSDS) were in the normal range and then they gradually decreased. The inhibin B (INHB), anti-Mullerian hormone (AMH), and testosterone (T) levels after human chorionic gonadotropin (HCG) stimulation and the T:DHT ratio in the male group were significantly higher than those in the female group (P < 0.001). The basal luteinizing hormone (LH), basal follicle-stimulating hormone (FSH), peak LH and peak FSH in females were significantly higher than those in males (P < 0.05). Their height showed a positive correlation with T levels after HCG stimulation (r = 0.636, P < 0.01), T:DHT ratio (r = 0.724, P < 0.01), growth hormone (GH) (r = 0.827, P < 0.05), and insulin-like growth factor 1 (IGF-1) (r = 0.067, P > 0.05) and a negative correlation with gonadal pathology in ovarian tissue (r = -0.663, P < 0.05) and the number of chimaeric XY cells (r = -0.533, P < 0.05).

Conclusions

Patients with 45,X/46,XY mosaicism have specific growth patterns. Their HtSDS was in the normal range during 0-2 years of age and then they began to show a short stature after 2 years of age. The probability of short stature in females was higher than that in males. WtSDS were all in the normal range, but below the median. BMISDS was in the normal range, and there was no evidence of obesity. The gonads in the male group retained a certain androgen secretion function, while the gonadal damage is more severe in the female group.

Surgery in Chinese children affected by 45,X/46,XY disorders of sex development: A 20-year experience in a single center

BACKGROUND

Children affected by 45,X/46,XY mosaicism have a wide spectrum in their phenotypes. Although surgery has a role in management, there is no universally agreed strategy.

METHODS

We conducted a retrospective review in a tertiary center on the surgical management and its long-term outcomes in children with the karyotype 45,X/46,XY or its variants over a 20-year study period. Patients were divided into 4 groups based on their phenotypes.

RESULTS

22 children(female=13, male=9) were included in the study, and were grouped as I)female phenotype(n = 11), II)ambiguous external genitalia(n = 2), III)undervirilized male with hypospadias(n = 6), and IV)normal male phenotype(n = 3). 19/22(86%) underwent gonadal surgeries(bilateral gonadectomy=15; unilateral gonadectomy=1; testicular biopsy=3) and  8/22(36%) underwent genitalia reconstructive surgeries(hypospadias repair=6; feminizing surgery=2). Gonadal germ cell tumors were detected in 55%, 50% and 50% of Group I, II and III respectively. 3/6 patients required reoperations for complications after hypospadias repairs. None of the patients had recurrence of germ cell tumors after gonadectomy. All the patients who had reached late adolescence or adulthood maintained their genders as their sex of rearing.

CONCLUSIONS

Majority of 45,X/46,XY children benefit from timely gonadal surgery while genitalia reconstructive surgery can be considered in selected patients. Surgical management can be strategized by patients' phenotypes.

Early Bilateral Gonadoblastoma in a Patient with Mixed Gonadal Dysgenesis (Karyotype 45,X/46,XY): Case Report and Review of Literature

Background

Mixed gonadal dysgenesis is a rare congenital and challenging condition, characterized mainly by 45,X/46,XY karyotype mosaicism, asymmetrical gonadal development and various internal and external genital anatomy. Because of frequent disorder of genital development and a higher risk of germ cell neoplasia, management of these patients is complex and requires multidisciplinary approach.

Case

We present a 45,X/46,XY mixed gonadal dysgenesis patient diagnosed with gonadoblastoma in both gonads after bilateral gonadectomy at 1 year of age.

Conclusions

Because of high risk for malignant transformation, gonadectomy of a streak-like gonad and biopsy with orchidopexy or gonadectomy of a dysgenetic testicle is recommended at an early age.

Chance diagnosis of mixed gonadal dysgenesis in an adult case of malignant gonadal germ cell tumor: a case report

Background

Mixed gonadal dysgenesis (MGD) is a subtype of the disorders of sex development (DSD) associated with sex chromosome abnormalities characterized by abnormal external genitalia, short stature, and primary amenorrhea. This disease is generally diagnosed from the neonatal stage to early childhood, and by puberty at the latest. Cases that are phenotypically female or those with ambiguous genitalia experience a high risk of gonadal tumor formation. As tumor risk is known to increase with age, prophylactic bilateral gonadectomy is recommended following early diagnosis.

Case presentation

Here we report a case of an adult Japanese woman diagnosed with MGD during treatment for a giant pelvic tumor. The patient initially visited a gynecology clinic during puberty for primary amenorrhea, at which time an abnormality was found with the external genitalia. However, a diagnosis of MGD was not made at this time, resulting in the development of a malignant gonadal germ cell tumor in adulthood.

Conclusions

For early diagnosis of MGD and the prevention of gonadal tumor formation, it is essential that gynecologists fully understand MGD and other DSD.

Multidisciplinary Approach to the Child with Sex Chromosomal Mosaicism Including a Y-Containing Cell Line

Children born with sex chromosomal mosaicism including material derived from the Y chromosome may present with a broad phenotypical spectrum. Both boys and girls can present with Turner features and functional health problems typically associated with Turner syndrome, but the presence of Y-chromosomal material can modify some aspects of the condition. We retrospectively analyzed the results of our cohort of 21 individuals (14 boys, 7 girls) with sex chromosomal mosaicism including Y-derived material followed at Ghent University Hospital according to our local multidisciplinary Turner surveillance protocol. Results were compared with literature data, focusing on similarities and differences between girls and boys with this condition. Age at diagnosis was lower in boys compared to girls but the difference was not significant. Short stature is a key feature of the condition both in girls and boys, but skeletal maturation may be different between groups. The effects of growth-hormone therapy remain unclear. Cardiac (33%), ear-nose- throat (ENT) (77.8%) and renal (28.6%) problems were as prevalent in boys as in girls from our cohort, and did not differ from literature data. In line with literature reports, a significant difference in the presence of premalignant germ cell tumors between males (0%) and females (42.9%) was found (p = 0.026). Taken together, this study demonstrates the similarities between girls with Turner syndrome and children with sex chromosomal mosaicism including Y-derived material, regardless of the child’s gender. Nowadays, girls with Turner syndrome are offered a dedicated multidisciplinary follow-up in many centers. We advocate a similar follow-up program for all children who have sex chromosomal mosaicism that includes Y-derived material, with special attention to growth, cardiac and ear-nose-throat problems, gonadal function and malignancies.

Growth data and tumour risk of 32 Chinese children and adolescents with 45,X/46,XY mosaicism

BACKGROUND

The aim of this study was to review the growth data, gonadal function and tumour risk of children and adolescents with 45,X/46,XY mosaicism who presented to a single centre in China.

METHODS

We conducted a retrospective review of the records of 32 patients with 45,X/46,XY mosaicism or variants who were hospitalized from August 2005 to September 2018. The main outcomes measured were growth data, genital phenotype, gonadal function, gonadal position, and histological results.

RESULTS

A total of 32 patients were included. The age at diagnosis ranged from 0.6 to 16.3 years. Nineteen patients exhibited ambiguous genitalia, 12 had short stature, and 1 showed a lack of breast development. Seventeen patients were raised as males, and 15 were raised as females. The external masculinisation score (EMS) of patients raised as male was 4.5 (1~12) [median (range)]. The EMS of the females was 0 (0~1.5) [median (range)]. Patients showed normal heights under 2 years old, with a height SDS of 0 (- 1.5~1.4) [median (range)]. Growth appeared to decelerate after age 2 years, with SDS decreased to - 2.8 (- 3.0~ - 0.9) [median (range)]. The percentage of short stature was higher in females than in males (76.9% vs 50.0%). Twenty-five patients had gonadal pathological results. Complete gonadal dysgenesis (CGD) and mixed gonadal dysgenesis (MGD) were the most common pathogenic subtypes, accounting for 48.0 and 36.0%, respectively. Ovotesticular tissue was observed in only 4.0% of patients. Gonadoblastoma and positive OCT3/4 results were found in 18.8% of gonads in children over 2 years of age. Palpable gonads accounted for 50% of these. All patients who had gonadoblastoma were raised as females.

CONCLUSIONS

Patients with 45,X/46,XY might have normal heights until 2 years old. Growth decelerations after 2 years of age were common. Patients who are being raised as females seemed to be shorter than males. CGD and MGD were the most common gonadal pathogenic subtypes. The tumour risk is high in these patients, even in palpable gonads and female patients.

The Dilemma of Sex of Rearing: A Case of a 45,X/46,XY Neonate with Hydrocolpos

BACKGROUND

A rare disorder of sex development is 45,X/46,XY mosaicism, which is phenotypically very heterogenous, ranging from normal male (or female) to that of genital ambiguity of varying degrees.

CASE

We report a case of a neonate with 45,X/46,XY mosaicism and hydrocolpos, and we point out the dilemma and the difficulty in gender assignment.

SUMMARY AND CONCLUSION

Gender assignment of cases with frank genital ambiguity is often difficult to be determined, because several factors have to be taken into consideration, such as genital appearance, anticipated urological and sexual function, capacity for future fertility, gonadal malignancy risk, and psychosocial factors. A multidisciplinary approach is definitely needed in the management of such cases.

The Clinical Manifestation and Genetic Evaluation in Patients with 45,X/46,XY Mosaicism

45,X/46,XY mosaicism is a rare chromosomal abnormality and probably underdiagnosed. Although clinical and genetic analyses have been performed in some disorders of sexual development, there have been few studies focusing on the phenotype and genetic details of 45,X/46,XY mosaicism, especially in the Chinese population. The aim of this study was to describe the experience of our service in relation to 16 cases with 45,X/46,XY mosaicism. The age at the first evaluation of the patients ranged from 43 days to 30 years. Eight patients were reared as female and 8 as male. The main reasons for examination were primary amenorrhea, sterility, or ambiguous genitalia. Short stature was more common in female than in male patients. Two patients accepted gonadectomy due to tumor risk and none presented gonadal malignancy. The SRY gene was amplified positively in all of the patients. AZF gene microdeletions were present in 6 of 8 male patients, and all adult male patients had no sperm. No correlation has been found between clinical manifestations and the proportion of mosaic cells in peripheral blood. Our observations may permit a better management of people with 45,X/46,XY mosaicism.

Tumor risk of children with 45,X/46,XY gonadal dysgenesis in relation to their clinical presentations: Further insights into the gonadal management

OBJECTIVE

To investigate the risk of gonadal germ cell neoplasms (GCN) in children with 45,X/46,XY gonadal dysgenesis and its relation to the clinical presentations.

METHODS

We conducted a retrospective study reviewing the clinical and gonadal features of all consecutive children with 45,X/46,XY gonadal dysgenesis who received gonadal management in a tertiary center from 1985 to 2015. Study subjects were divided into Group I(significant genitalia anomaly), Group II(female phenotype) and Group III(male phenotype).

RESULTS

21 children were studied (Group I=8; Group II=11; Group III=2). All 19 children of Group I and II eventually underwent bilateral gonadectomy. One patient of Group III underwent gonadal biopsy which showed increase in fibrous tissue in the testes without any GCN. 3/8(37.5%) and 6/11(54.5%) of patients in Group I and II respectively had either gonadoblastoma (GB) or carcinoma-in-situ (CIS) or both affecting one or both gonads. Among Group I patients, the 4 dysgenetic testes affected by CIS in 3 patients were intraabdominal (n=1), inguinal (n=1) and scrotal (n=2) in positions. Among Group II patients, 6/20 streak gonads had GB and 2/2 dysgenetic testes had GB or CIS.

CONCLUSIONS

45,X/46,XY children with significant genitalia anomaly or female phenotype are both at high risk of gonadal GCN.

Occurrence of Gonadoblastoma in Patients with 45,X/46,XY Mosaicism

STUDY OBJECTIVE

To estimate the overall frequency of gonadal tumors in patients with 45,X/46,XY mosaicism who underwent gonadectomy and to determine whether the degree of external masculinization or the location of gonads were associated with the presence of gonadal tumor.

DESIGN

Retrospective study of patients with karyotype of 45,X/46,XY or variant who received care at the study institution between 1995 and 2012.

SETTING

University of Michigan Health System (Ann Arbor, Michigan), a tertiary care academic center.

PARTICIPANTS

Sixteen patients with karyotype of 45,X/46,XY who underwent gonadectomy.

INTERVENTIONS

None.

MAIN OUTCOME MEASURE

Presence of pathology-confirmed gonadal tumor.

RESULTS

In patients who underwent bilateral gonadectomy, gonadoblastomas were detected in 36.4% (4 of 11), and all were identified in patients with normal female external genitalia (4 of 8 [50.0%]). Abdominal gonads were associated with a nonsignificant increase in rate of gonadal tumor compared with inguinal or scrotal gonads. No malignant tumors were identified.

CONCLUSION

The overall rate of gonadoblastoma was higher than previously reported. The high rate of gonadoblastoma in patients with female external genitalia and the lack of gonadal function support continuing the standard of care of practice of prophylactic gonadectomy in this patient population.