Clinical Management in Mixed Gonadal Dysgenesis with Chromosomal Mosaicism: Considerations in Newborns and Adolescents

Abstract

Individuals born on the spectrum of genetic abnormalities known as mixed gonadal dysgenesis (MGD) have a wide range of anatomical findings and management can be challenging in the newborn and adolescent. Historically, many individuals with MGD have undergone gonadectomy to avert the risk of gonadal malignancy. However, gonadectomy deprives patients of the benefits of their endogenous hormones, potential fertility, and in the case with MGD, has historically been done prior to addressing gender identity. Some patient advocates have proposed a delayed approach to surgical reconstructions and/or gonadectomy in other differences/disorders of sex development (DSD), particularly in patients with congenital adrenal hyperplasia and androgen insensitivity syndrome. In many areas of the world, there continues to be a shift toward delayed reconstructions and hesitancy regarding irreversible gonadectomy. To date, no clinical management protocol addressing these issues from a patient-centered approach has been described. We review what is known about malignancy risk and propose a management protocol for those with MGD that involves shared decision making regarding the gonads and addresses the long-term challenges with regard to gender and anatomy.

Introduction

Mixed gonadal dysgenesis (MGD) is a term used to describe individuals who have chromosomal mosaicism as well as dysgenetic gonads and variable internal and external reproductive anatomy. The term was refined with the 2006 Consensus Statement in which chromosomal conditions were classified into new, separate categories.¹ The 2016 updated Consensus Statement included the term ‘chimerism’ under the category that lists MGD.² Clinical presentation can be on a spectrum with varying chromosomal arrays (e.g. 45,X/46,XY or 46,XX/46,XY and others) as well as varying gonadal characterizations (e.g. streak gonads or normal ovaries/testes). Due to this clinical variation, the true prevalence of MGD is unknown.

MGD is currently managed by the removal of the gonadal tissue, typically at an early age. This is in large part due to the high reported malignancy risk. Some estimates indicate that there is a 15–35% risk of developing germ cell tumors (GCT) with gonadoblastoma being the most common tumor seen in this patient population.³ However, the true malignancy risk is difficult to ascertain when many different phenotypes are included under the MGD umbrella. Patient advocacy groups state that physicians should wait on medical decisions until a patient is old enough and has the autonomy to decide, especially regarding irreversible surgeries. This approach may not be applicable to a population with a reported high malignancy rate. Therefore, clinicians need to consider the individual risk as well as an individualized clinical pathway, which is best suited for the patient.

Current Management

The management of MGD has been described as one of the most complex clinical situations as many factors need to be considered when making decisions. Issues that families and providers must weigh include the presence of both male and female structures, malignancy risk, infertility, gender identity and dysphoria, family dynamics, social adaptation and coping skills.⁴ Consequently, there is no universally agreed upon treatment strategy.⁵

In the past, these patients commonly underwent feminizing surgery in the neonatal period; proposed options include assigning male gender to DSD patients with Y chromosome material or delaying irreversible surgery altogether.^6–10 However, practice continues to vary throughout the world. A recent small series of three complex cases of mixed chromosomal DSD describes a multidisciplinary approach that included a spectrum of choices. These include: 1. Masculinization with removal of dysgenetic ovary; 2. Initial vaginoplasty but with retention of phallus and +/− bilateral gonadectomy; 3. Initial vaginoplasty with “burial” of corporal bodies and +/− bilateral gonadectomy; 4. Full feminization: vaginoplasty and clitoroplasty with bilateral gonadectomy and; 5. No surgical intervention.¹¹ All three families chose option two with bilateral gonadectomy, which the authors felt was the best scenario for preservation of the anatomy, parental preference, and future patient autonomy in the setting of testosterone exposure to the neonatal brain. A 2013 case series of 31 patients over a 21-year period in United Kingdom (UK) also stresses the importance of a multidisciplinary approach including endocrinologists, pediatric urologists, genetics, gynecologists, and clinical psychologists.¹⁰ Diagnostic laparoscopy and cystoscopy were pursued at two to three months of age and further surgical procedures depend on gender of rearing. For males, intraabdominal gonads were biopsied and first stage Fowler-Stephens procedure performed. Orchidopexy was done for palpable but undescended testes by one year of age, and hypospadias repair was done at one to two years of age. The surgical reconstruction and timing of such were more varied for the female patients but gonadectomy was almost always performed.¹⁰ Gonadectomy for streak and dysgenetic testes typically occurred between three and six months of age for a group of patients in France in the late 1990s and a 2005 study from Mexico advocates for early gonadectomy.^{12, 13} A 2019 Taiwanese study recommends gonadectomy for intraabdominal streak gonads or dysgenetic gonads.¹⁴

Over the last decade, two proposed treatment algorithms have emerged for the management of MGD, focusing mainly on the management of the gonads. Cools et al. stratified patients based on an external masculinization score; tumor risk was related to the clinical phenotype with the highest risk of malignancy in those patients with ambiguous genitalia.¹⁵ Accordingly, their management guidelines divide patients into three groups and treatment strategies: 1. Mild undervirilization where orchidopexy, biopsy and post-puberty surveillance with self-exams every three months; annual ultrasounds are performed; 2. Ambiguous genitalia for which there is a lower threshold to perform gonadectomy and; 3. Female phenotype where elective gonadectomy is recommended.¹⁵ The surgical management of gonads with an increased malignancy risk proposed by Wolffenbuttel et al. similarly advocates for biopsy and gonad relocation to a region where it can be surveilled by self-exam and imaging.⁵ A plan is determined for either early gonadectomy, if the gonad is unable to be relocated or already shows signs of malignancy, or later gonadectomy depending on hormone secretion, compliance with surveillance and/or patient preference.⁵

This paper aims to discuss the current protocols, while also providing the healthcare team and family practical steps and shared decision-making tools for the multidisciplinary care of these patients from the neonatal period through the adolescent years.

Malignancy Risk and Considerations

Germ cell tumors (GCT) are at an increased prevalence in individuals with a DSD where a Y chromosome is present, and the risk may be higher depending on how much Y material is present. The specific location on the Y chromosome that has been identified is the gonadoblastoma location known as the GBY region.¹⁶ It has been suggested that the combination of the OCT3/4 and TSPY expression in germ cells are responsible for tumor development in patients with DSD.^{3, 17} Some reports have discussed the malignancy risk to be as low as 2% while others have placed it as high as 35%.^{17, 18}

The age of the patient may also matter for GCT development. There have been reports of carcinoma in situ (CIS) discovered in children as young as three months of age and GCTs found in children as young as one year of age.^{17, 19} The risk may be lower at the pre-pubertal age and gonadectomy may be deferred until older with careful monitoring and risk assessments.¹⁵ Manuel et al. described the risk for those who are 10 years of age is 2%, 5% at 14 years of age, 16% at 20 years of age, and 27.5% at 30 years of age.¹⁸ However, the cited risk was based off samples included in their study and has not been replicated recently. It has been suggested that tumor risk is increased in patients with poorly differentiated gonadal tissue.¹⁵

As previously mentioned, Cools et al. developed an algorithm to determine the individual level of risk in MGD.^{3, 15} They stated upon initial diagnosis and upon determining the type of gonadal tissue present, one could subsequently determine immediate need or deferment of gonadectomy until a later date. Wolffenbuttel et al. describe their algorithm for perceived risk of GCT and subsequent clinical pathway.⁵ However, neither protocol takes into consideration other important patient aspects such as gender identity, hormonal considerations post-gonadectomy, and fertility potential.

Proposed Management

Shared Decision-Making (SDM)

To determine the best course of action concerning sex of rearing or gonad removal, a SDM process should be initiated when a patient is first diagnosed with MGD. The management protocol proposed by Cools and colleagues is discussed with the patients and parents (see Figure 1).¹⁵ Diagnosis confirmation based on physical exam, surgical and pathological presentation as well as chromosomal analysis is imperative prior to treatment decision-making in order to understand fully the malignancy risks as well as fertility potential. The SDM process involves counseling sessions, occurring at multiple time points with up-to-date information on outcomes, current care models and risks and benefits of all treatment options. A SDM tool can be utilized to guide and document discussions for patients and families dealing with two scenarios: a newborn with possible MGD and an adolescent who may or may not have had reconstructions or gonadectomy as a young child. We have created SDM checklists for each of the groups that address all relevant issues (Supplementary Figs. 2 and 3).

Figure 1. MGD Management Algorithm.

This figure shows a treatment algorithm, modified from Cools et al,¹⁵ to assess malignancy risk and determine an individualized treatment plan for individuals diagnosed with 45,X/46,XY gonadal dysgenesis with mosaicism.

Gender Identity

Male and female gender of rearing have been recommended for those with MGD.^{12, 20–22} Further, the Consensus Statement encourages considerations for prenatal androgen exposure levels, gonadal function at and after puberty, phallic size, and location of gonads when assigning gender at birth.¹ However, if the risk in developing GCTs is determined to be low, and especially in instances where there is a low risk until the child reaches puberty and/or an age where they are feeling more confident about gender identity, gonadectomy may be deferred. When counseling patients with MGD, discussions surrounding the emotional effect of gender-discordant gonads or the effects gonads may have on gender identity (e.g. masculinizing hormones in individual who identifies as female gender) should occur.

Hormonal Considerations

The question of whether hormone replacement is equivalent to endogenous hormones has not been answered in the literature. Recent studies of women with post-surgical hypogonadism highlight the possible negative effect of hormone replacement on cardiovascular health and mortality.^{23, 24} In individuals with CAIS, low bone mineral density (BMD) has been linked to a combination of decreased estrogen and skeletal resistance to androgen action.^{25, 26} Gonadectomy may have a similar impact on the cardiovascular and bone of individuals with MGD, requiring further investigation in this patient population.

Fertility Considerations

Germ cells have been reported in 68% of gonad samples from children with a variety of DSD with germ cells being found in 6/6 MGD patients.²⁷ As such, consideration should be given to fertility preservation (FP) in these individuals. While individuals with MGD may have abundant germ cells present at younger age, this may change as a person ages and needs to be taken into consideration as well.^{8, 28–30} Counseling sessions for patient and families should include discussion about FP potential and reproductive repercussions. Optimal timing of gonadectomy based on consideration of preservation of endogenous hormone function and fertility potential needs to be discussed.³¹

Ethical Considerations

Efforts in healthcare reform have encouraged medical providers to shift from a paternalistic view of decision-making to one where the patient and family are engaged in the process.³² Further, there are governmental and human rights organizations who contend that the child has a right to bodily autonomy decision-making, especially in the case of irreversible surgeries.^33–39 The American Medical Association (AMA) Board of Trustees issued a report recommending that care “respect the rights of the patient to participate in decisions and, except when life-threatening circumstances require emergency intervention, defers medical or surgical intervention until the child is able to participate in decision making”.³⁹ The AMA also portends that withholding information from any patient is unethical and goes against current practice for patients living with a DSD.⁴⁰

Physical Exam

Neonatal

Wide phenotypic variation exists for patients with a postnatal diagnosis of 45,X/46XY ranging from phenotypic males with cryptorchidism or hypospadias, phenotypic females with gonadal dysgenesis, and the more common presentation of one testis, one streak gonad and Mullerian structures. Interestingly, 90–95% of patients with a prenatal diagnosis of 45,X/46,XY will be phenotypically normal male.^{10, 13} Physical exam findings can also help to distinguish MGD from Turner Syndrome. Patients with Turner syndrome may have misshapen ears, webbed neck, broad/shield-shaped chest with widely spaced nipples, and cubitus valgus.⁴¹ Given the incidence of associated cardiac anomalies, a careful cardiovascular exam is warranted. Perhaps the most important aspect of the physical exam is to ensure there is no urinary or vaginal obstruction that would require immediate intervention in the neonatal period.

Adolescent

Whether reconstructive surgeries and/or gonadectomy was performed in the early years or not, adolescent and young adult patients with MGD may require or desire further reconstruction. For patients with a hemiuterus and hemivagina, there can be a urogenital sinus with a short common channel and a discussion regarding the indication for repair depends on the goals of the patient. If the goal is penetrative sexual activity, all options must be discussed including dilator therapy and surgical vaginoplasty and/or introitoplasty. If there is an enlarged clitoris, a discussion about sexual activity and function of the clitoris must occur prior to any further intervention or primary intervention. This necessitates a high level of maturity on the part of the patient to ensure that assent can be given for any procedures. Use of a SDM tool with the affected individual, family and personal advocates and trusted providers is essential to the process and can take many years. The process is similar to the WPATH guidelines for transgender youth and should always involve psychosocial assessment and involvement of mental health team members.⁴²

Karyotype and Laboratory Studies

As mentioned before, some of the confusion/controversy in the management of MGD stems from the lack of consensus terminology over decades of research and care of these patients. The 2016 consensus statement on Management of Intersex Disorders defines MGD as 45,X/46,XY or 46,XX/46,XY which can be determined by karyotype.² A mosaic chromosome analysis evaluating at least 50 cells should be performed. There are no studies that analyze the utility of serum markers such as Beta-human chorionic gonadotropin, alpha-fetoprotein, placental-like alkaline phosphatase, octamer binding transcription factor 3/4 or testis-specific protein-Y encoded, for the diagnosis or follow up of gonad tumors in DSD patients.³

Imaging Studies

For those patients who do undergo orchidopexy, we recommend a contrast-enhanced magnetic resonance imaging (MRI) of the abdomen and pelvis as a baseline step and especially in those in which the gonads are not well visualized on ultrasound (US). One study compared MRI imaging with histologic findings in gonads post-gonadectomy and found that MRI correlated well with histology of macroscopic findings and could depict the gonads sufficiently.⁴³ Another study compared the utility of MRI to ultrasound for a broad population of DSD patients who underwent either imaging modality prior to prophylactic gonadectomy and found no imaging characteristics to suggest premalignant or malignant lesions. The authors found no difference between US or MRI in terms of ability to identify gonads.⁴⁴ Therefore, US should be considered the first-line imaging study of choice due to the increased costs associated with MRI. It is recommended that patients undergo a baseline MRI scan, with repeat scans every five years, and annual US until imaging becomes more reliable between centers. It should be noted that a recent retrospective study of ten patients with gonadal dysgenesis and non-palpable gonads showed both US and MRI lack of consistent imaging findings of malignancy. Three of the four patients who had malignancy on final pathology had preoperative imaging studies that described the gonads as normal or small.⁴⁵ The risk of germ cell tumors in cryptorchidism in non-DSD patients is known to be four to ten times higher than the prevalence of six to eleven per 100,000, and the standard of care for surveillance of these patients after orchidopexy is annual physical exam by provider and every three month self-exam.⁴⁶

Diagnostic Laparoscopy and Exam under Anesthesia

The purpose of the first surgical evaluation is to take inventory of the structures and identify any abnormalities that require immediate attention. A multidisciplinary team with pediatric surgery, urology, and gynecology can be helpful in the approach of these complex cases. Concurrent diagnostic laparoscopy and cystoscopy/ vaginoscopy can identify the anatomical course of the pelvic structures. The gonads of patients with MGD may be abnormal in size, color, shape and consistency but macroscopic findings do not reliably predict histology. Yellow-brown spots on the surface of dysgenetic gonads may represent ectopic seminiferous tubules within the tunica albuginea.⁵ The 2012 UK series pursues this surgery at two to three months of age whereas we prefer to wait until the six month age range or later to encourage family bonding in the neonatal time period and to take the emphasis off of the genitalia as the most important part of the infant’s care.¹⁰

Gonadal Biopsy and Immunohistochemical Staining

For adequate biopsy, a unilateral sample size of 3×3×2mm has been suggested in the case of homogenous gonads. If a yellow-brown spot is seen, a thin strip of tunica incorporating the spot should be taken with the biopsy. The tunica albuginea is then closed with fine, interrupted absorbable suture. Several representative biopsies may be performed for heterogenous gonads.⁵ Immunohistochemical gonad staining was studied in a large series of intersex patients and revealed characteristic staining of OCT3/4 and overexpression of TSPY making these IHC markers useful in the diagnosis of carcinoma in situ (CIS) and gonadoblastoma.¹⁰ However, histological findings of CIS can closely resemble the primitive gonocyte/maturation delay. OCT3/4 staining in germ cell carcinoma precursor lesions is often found in clusters at the level of the basal lamina of the tubules.³ Conversely, stem cell factor, also known as c-KIT ligand (KITLG), is only found in cases of GCNIS (germ cell neoplasia in situ) or gonadoblastoma and is not found in maturation delay.⁴⁷

Annual Follow-up and Surveillance

For patients who are followed without gonadectomy or with partial removal of gonadal tissue, an annual visit with a multidisciplinary team is necessary. If the gonads have undergone placement in the scrotum, self-exams every three months and annual imaging is essential to monitor for abnormalities that may warrant biopsy of retained gonads. Ongoing social and peer support for the patient and family is also suggested along with participation in a long-term registry with metrics that screen for depression, anxiety and altered body self-image is ideal.

Conclusion

Patients with MGD deserve a comprehensive long-term management approach that allows them to thrive in childhood, adolescence and young adulthood. The issues that affect all individuals with DSD apply to this group of diverse and complex patients, including decisions regarding gonadal management, gender identity, fertility, social acceptance, dating and hormonal therapy if the gonads have been removed. An individualized approach allowing for patient autonomy and self-direction should be encouraged.