Molecular Karyotyping in Children and Adolescents with Gender Dysphoria

Clinical features and prevalence of Klinefelter syndrome in transgender individuals: A systematic review

OBJECTIVE

Previous studies have suggested a higher prevalence of Klinefelter syndrome amongst transgender individuals. We undertook a systematic review to determine the prevalence of Klinefelter syndrome amongst transgender individuals presumed male at birth and summarize the clinical features and potential treatment implications for individuals with Klinefelter syndrome commencing gender-affirming hormone therapy.

DESIGN

Using preferred reporting items for systematic review and meta-analysis guidelines, we searched EMBASE, MEDLINE and the Cochrane Central Register of Controlled Trials (CENTRAL) up to 31 December 2021. All studies reporting on the prevalence or clinical features of transgender individuals with Klinefelter syndrome were included. This study is registered with the International Prospective Register of Systematic Reviews, number CRD42021227916.

RESULTS

Our search strategy retrieved 11 cohort studies comprising 1376 transgender individuals. In all, 14 of 1376 (1.02%) individuals were diagnosed with Klinefelter syndrome. Based on the seven studies in which karyotype was undertaken in all individuals, the prevalence is 9/1013 (0.88%; 95% CI, 0.41%-1.68%). Case reports highlight unique treatment considerations in this population, including azoospermia, venous thromboembolism, and monitoring of breast cancer and bone health.

CONCLUSIONS

Compared to the general population, observational studies document a higher prevalence of Klinefelter syndrome amongst transgender individuals, though underdiagnosis in the general population limits conclusions. Routine karyotype in transgender people initiating gender-affirming hormone therapy is not supported unless clinical features of Klinefelter syndrome, such as small testicular volume, or hypergonadotropic hypogonadism are present. Transgender individuals with Klinefelter syndrome need to manage a unique risk profile if they desire feminizing gender-affirming hormone therapy.

Should chromosomal analysis be performed routinely during the baseline evaluation of the gender affirmation process? The outcomes of a large cohort of gender dysphoric individuals

The role of genetics in the etiology of gender dysphoria (GD) is an important yet understudied area. Yet whether genetic analysis should be carried out during the gender affirmation process at all is a matter of debate. This study aims to evaluate the cytogenetic and molecular genetic findings of individuals with GD. We retrospectively reviewed the medical records of individuals with GD who were followed up in a tertiary clinic. After the exclusion criteria were applied, the study sample consisted of 918 individuals with GD; 691 of whom had female-to-male (FtM) and 227 male-to-female (MtF) GD. The cytogenetic analysis revealed that 223 out of 227 (98.2%) individuals with MtF GD had the 46,XY karyotype, while 683 out of 691 (98.8%) individuals with FtM GD had the 46,XX karyotype. In the Y chromosome microdeletion analysis, azospermic factor c (AZFc) deletion was detected in only two individuals with MtF GD. Our findings suggest that there are few chromosomal abnormalities in individuals with GD. Thus, this research calls into question both the role of chromosomal abnormalities in GD etiology and why the application of chromosomal analysis is in Turkey a routine part of the baseline evaluation of GD.

Gender Variance in Children and Adolescents with Neurodevelopmental and Psychiatric Conditions from Australia

Gender variance is a broad term used to describe gender non-conforming behaviors. Past studies have used the parental response to Child Behavior Checklist (CBCL) Item 110, which asks whether a child "Wishes to be of opposite sex" as an indicator of gender variance. The population prevalence of gender variance in children and adolescents using this metric was found to be 1.2% in birth-assigned females and 0.4% in birth-assigned males (Achenbach & Rescorla, 2001). However, in those referred for psychiatric evaluation, it was higher (5.4% of birth-assigned females and 2.8% of birth-assigned males) (Achenbach & Rescorla, 2001). The aim of this study was to use the CBCL to estimate the prevalence of gender variance among children and adolescents with neurodevelopmental and psychiatric conditions and assess whether this was higher compared to controls. The response to the CBCL and the child's neurodevelopmental and/or psychiatric diagnosis were extracted from the clinical notes of 1553 children and adolescents referred to an outpatient psychiatry clinic in Australia. This was compared to data from 181 control participants as well as to the CBCL standardization sample of 1605 controls. Of the 1553 young people, whose mean age was 10.9 years, gender variance was reported in 3.1% compared to 1.7% in local control participants (p > .05) and 0.7% in the CBCL controls (p < .0001). Rates varied depending upon the underlying diagnosis (ASD 5.2%; ADHD 2.5%, intellectual disability 4.7%; depression 2.6%; and anxiety 4.7%). In this way, our findings support past observations that young people with neurodevelopmental and psychiatric conditions have high rates of gender variance.

Gender dysphoria in children and adolescents: an overview

Over the last decade, we have witnessed considerable progress in gender dysphoria (GD) terminology in an attempt to better describe the condition based on certain criteria. The ever-increasing social acceptance and destigmatization of children and adolescents with GD have resulted in an increased number of transgender individuals seeking endocrine care. In addition to terminology and diagnostic criteria, the tremendous progress of genetics and neuroimaging has enabled us to have a deeper understanding of the complex pathogenesis of GD. Although helpful guidelines for treatment with GnRH analogs and gender-affirming hormones have been proposed, several challenges and controversies still exist. In this article, the current knowledge about GD in adolescents is reviewed, with particular emphasis on terminology, clinical manifestations, and epidemiologic data. The neurobiological basis of the condition is presented, and both hormonal treatment and mental issues of transgender individuals are discussed. Undoubtedly, further research will optimize the diagnostic and therapeutic approach of children and adolescents with GD.

Parent-of-Origin Effects in 15q11.2 BP1-BP2 Microdeletion (Burnside-Butler) Syndrome

To identify whether parent-of-origin effects (POE) of the 15q11.2 BP1-BP2 microdeletion are associated with differences in clinical features in individuals inheriting the deletion, we collected 71 individuals reported with phenotypic data and known inheritance from a clinical cohort, a research cohort, the DECIPHER database, and the primary literature. Chi-squared and Mann-Whitney U tests were used to test for differences in specific and grouped clinical symptoms based on parental inheritance and proband gender. Analyses controlled for sibling sets and individuals with additional variants of uncertain significance (VOUS). Among all probands, maternal deletions were associated with macrocephaly (p = 0.016) and autism spectrum disorder (ASD; p = 0.02), while paternal deletions were associated with congenital heart disease (CHD; p = 0.004). Excluding sibling sets, maternal deletions were associated with epilepsy as well as macrocephaly (p < 0.05), while paternal deletions were associated with CHD and abnormal muscular phenotypes (p < 0.05). Excluding sibling sets and probands with an additional VOUS, maternal deletions were associated with epilepsy (p = 0.019) and paternal deletions associated with muscular phenotypes (p = 0.008). Significant gender-based differences were also observed. Our results supported POEs of this deletion and included macrocephaly, epilepsy and ASD in maternal deletions with CHD and abnormal muscular phenotypes seen in paternal deletions.