Clinical phenotype and management of individuals with mosaic monosomy X with Y chromosome material stratified by genital phenotype

Clinical practice guidelines for the care of girls and women with Turner syndrome

Turner syndrome (TS) affects 50 per 100 000 females. TS affects multiple organs through all stages of life, necessitating multidisciplinary care. This guideline extends previous ones and includes important new advances, within diagnostics and genetics, estrogen treatment, fertility, co-morbidities, and neurocognition and neuropsychology. Exploratory meetings were held in 2021 in Europe and United States culminating with a consensus meeting in Aarhus, Denmark in June 2023. Prior to this, eight groups addressed important areas in TS care: (1) diagnosis and genetics, (2) growth, (3) puberty and estrogen treatment, (4) cardiovascular health, (5) transition, (6) fertility assessment, monitoring, and counselling, (7) health surveillance for comorbidities throughout the lifespan, and (8) neurocognition and its implications for mental health and well-being. Each group produced proposals for the present guidelines, which were meticulously discussed by the entire group. Four pertinent questions were submitted for formal GRADE (Grading of Recommendations, Assessment, Development and Evaluation) evaluation with systematic review of the literature. The guidelines project was initiated by the European Society for Endocrinology and the Pediatric Endocrine Society, in collaboration with members from the European Society for Pediatric Endocrinology, the European Society of Human Reproduction and Embryology, the European Reference Network on Rare Endocrine Conditions, the Society for Endocrinology, and the European Society of Cardiology, Japanese Society for Pediatric Endocrinology, Australia and New Zealand Society for Pediatric Endocrinology and Diabetes, Latin American Society for Pediatric Endocrinology, Arab Society for Pediatric Endocrinology and Diabetes, and the Asia Pacific Pediatric Endocrine Society. Advocacy groups appointed representatives for pre-meeting discussions and the consensus meeting.

Phenotypic variability and management of patients with mosaic monosomy X and Y chromosome material: a case series

BACKGROUND

we aim to discuss the origin and the differences of the phenotypic features and the management care of rare form of disorder of sex development due to Mosaic monosomy X and Y chromosome materiel.

METHODS

We report our experience with patients harboring mosaic monosomy X and Y chromosome material diagnosed by blood cells karyotypes and cared for in our department from 2005 to 2022.

RESULTS

We have included five infants in our study. The current average age was 8 years. In four cases, the diagnosis was still after born and it was at the age of 15 years in one case. Physical examination revealed a variable degree of virilization, ranging from a normal male phallus with unilateral ectopic gonad to ambiguous with a genital tubercle and bilateral not palpable gonads in four cases and normal female external genitalia in patient 5. Karyotype found 45, X/46, XY mosaicism in patient 1 and 2 and 45, X/46, X, der (Y) mosaicism in patient 3, 4 and 5. Three cases were assigned to male gender and two cases were assigned to female. After radiologic and histologic exploration, four patients had been explored by laparoscopy to perform gonadectomy in two cases and Mullerian derivative resection in the other. Urethroplasty was done in two cases of posterior hypospadias. Gender identity was concordant with the sex of assignment at birth in only 3 cases.

CONCLUSION

Because of the phenotypic heterogeneity of this sexual disorders and the variability of its management care, then the decision should rely on a multidisciplinary team approach.

45,X/46,XY mosaicism: Clinical manifestations and long term follow-up

45,X/46,XY chromosomal mosaicism presents a range of clinical manifestations, including phenotypes from Turner syndrome through genital abnormalities to apparently unaffected phenotypic males; however, the full clinical spectrum has not yet been fully delineated since prior studies on the clinical phenotype and associated risk of gonadal tumors included small cohorts and limited follow-up. To better describe the clinical manifestations and long-term outcome of patients with 45,X/46,XY mosaicism. We conducted a retrospective chart review of patients with 45,X/46,XY from three health centers (Hospital for Sick Children and Mount Sinai Hospital in Canada, and University of Pittsburgh Medical Center in United States). Of 100 patients with 45,X/46,XY karyotype, 47 were raised as females and 53 as males. Females were significantly shorter than males (p = 0.04) and height Z-score was significantly decreased with age for both genders (p = 0.02). Growth hormone (GH) treatment did not result in a significant height increase compared to the untreated group (p = 0.5). All females required puberty induction in contrast to majority of males. Five females were diagnosed with gonadal tumors, while no males were affected. Around 58% of patients exhibited at least one Turner syndrome stigmata. This study expands the clinical spectrum, long-term outcomes, and associated tumor risk in a large cohort of patients with 45,X/46,XY mosaicism. Additionally, it highlights our experience with GH therapy and prophylactic gonadectomy.

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.

Individuals with numerical and structural variations of sex chromosomes: interdisciplinary management with focus on fertility potential

Diagnosis and management of individuals who have differences of sex development (DSD) due to numerical or structural variations of sex chromosomes (NSVSC) remains challenging. Girls who have Turner syndrome (45X) may present with varying phenotypic features, from classical/severe to minor, and some remain undiagnosed. Boys and girls who have 45,X/46,XY chromosomal mosaicism may have Turner syndrome-like features and short stature; therefore, unexplained short stature during childhood requires karyotype analysis in both sexes, particularly if characteristic features or atypical genitalia are present. Many individuals with Klinefelter syndrome (47XXY) remain undiagnosed or are only diagnosed as adults due to fertility problems. Newborn screening by heel prick tests could potentially identify sex chromosome variations but would have ethical and financial implications, and in-depth cost-benefit analyses are needed before nationwide screening can be introduced. Most individuals who have NSVSC have lifelong co-morbidities and healthcare should be holistic, personalized and centralized, with a focus on information, psychosocial support and shared decision-making. Fertility potential should be assessed individually and discussed at an appropriate age. Oocyte or ovarian tissue cryopreservation is possible in some women who have Turner syndrome and live births have been reported following assisted reproductive technology (ART). Testicular sperm cell extraction (TESE) is possible in some men who have 45,X/46,XY mosaicism, but there is no established protocol and no reported fathering of children. Some men with Klinefelter syndrome can now father a child following TESE and ART, with multiple reports of healthy live births. Children who have NSVSC, their parents and DSD team members need to address possibilities and ethical questions relating to potential fertility preservation, with guidelines and international studies still needed.

Differences of sexual development: genetic counseling considerations in the prenatal setting

PURPOSE OF REVIEW

With the rapid adoption of noninvasive prenatal screening (NIPS), predictive fetal sex information is available early in pregnancy. This information can conflict with the results of other prenatal tests such as fetal ultrasound or diagnostic testing and raise the possibility of a fetal difference of sexual development (DSD). In this review, we describe recent studies examining the counseling and outcomes of prenatally suspected DSD.

RECENT FINDINGS

Discordance in prenatal genetic testing results can cause confusion and anxiety in families as expectations of testing are not often discussed in detail prior to testing. There are no established guidelines for the counseling or management of such situations.

SUMMARY

We present case vignettes to highlight relevant counseling points and considerations to aid in the development of guidelines and best practices in the management of DSD in the prenatal setting.

A Rare Chromosome Rearrangement Leading to de la Chapelle Syndrome with a Mosaic 45,X Cell Line: (46,X,psu dic(X;Y)(p22.13;q11.221)/45,X/45,psu dic(X;Y)(p22.13;q11.221)

Infertility affects about 15% of couples of childbearing age. About half of these cases can be attributed predominantly to a male factor, such as a quantitative or qualitative impairment in spermatogenesis. The first-line genetic screening for non-obstructive azoospermia is limited to karyotyping (to identify chromosome abnormalities) and Y chromosome microdeletions screening, with a view to explaining the spermatogenetic failure and evaluating the likelihood of sperm retrieval in a testicular biopsy. For patients with de la Chapelle syndrome (a 46,XX karyotype with the presence of SRY (Sex determining region Y) gene) and/or Y chromosome microdeletions, or sex chromosome mosaicism, sperm retrieval is usually unsuccessful. Here, we report a patient with de la Chapelle syndrome and a short stature caused by mosaicism and a very rare chromosome rearrangement: mos 46,X,psu dic(X;Y)/45,X/45,psu dic(X;Y). This case indicates that in de la Chapelle syndrome, X- and Y-chromosome breakpoint variability is high.

Can Boys Have Turner Syndrome? More than a Question of Semantics

Individuals with 45,X mosaicism with Y chromosome material raised as boys are not diagnosed with Turner syndrome, a label restricted to phenotypic females. We sought to determine if boys with 45,X mosaicism had features consistent with Turner syndrome. Twenty-two patients (14 girls, 8 boys) seen in our Differences of Sex Development (DSD) clinic were identified for review. Standardized height (z-scores) by sex of rearing and results of cardiology, renal, audiology, thyroid, and celiac screenings were recorded. All subjects had heights below the mean for sex. Z-scores were not significantly different between boys and girls (p = 0.185). There were no significant differences in the incidence of cardiac anomalies between boys and girls (p = 0.08). Girls were more likely to have additional screenings (p = 0.042), but there were no significant differences in the number of positive screenings between boys and girls (p = 0.332). Patients with 45,X mosaicism raised as boys appear to have features similar to patients with the same karyotype raised as girls. Routine screening of boys following the Turner Syndrome Clinical Practice Guidelines may allow early recognition of comorbidities. Additionally, obtaining karyotypes on boys with short stature or other features of Turner syndrome may identify unrecognized cases of 45,X mosaicism.