Endocrinopathies and cardiopathies in patients with Turner syndrome

Uncommon presentation: monozygotic twins with Turner syndrome

Turner syndrome (TS) affects approximately 1 in 2500 female live births globally, making it the most common sex chromosomal abnormality in females. It results from a partially or completely missing X chromosome, often occurring in mosaic karyotypes. TS is associated with various health issues, including short stature, delayed puberty, ovarian dysgenesis, hypergonadotropic hypogonadism, infertility, congenital heart defects, endocrine disorders and autoimmune disorders. TS is less prevalent among twins. Since the first case report in 1938, the association between TS and twinning has been noted in only 30 cases worldwide. However, only six reports exist of monozygotic non-mosaic twins with TS, all 45,XO. Although TS affects individuals worldwide, the literature on TS in Asian twins is sparse, with no reported cases from Asia. This scarcity underscores the need for further research to understand this region's epidemiology and challenges. This case report highlights the importance of evaluating both twins if one is diagnosed with TS.

Organ Abnormalities Caused by Turner Syndrome

Turner syndrome (TS), a genetic disorder due to incomplete dosage compensation of X-linked genes, affects multiple organ systems, leading to hypogonadotropic hypogonadism, short stature, cardiovascular and vascular abnormalities, liver disease, renal abnormalities, brain abnormalities, and skeletal problems. Patients with TS experience premature ovarian failure with a rapid decline in ovarian function caused by germ cell depletion, and pregnancies carry a high risk of adverse maternal and fetal outcomes. Aortic abnormalities, heart defects, obesity, hypertension, and liver abnormalities, such as steatosis, steatohepatitis, biliary involvement, liver cirrhosis, and nodular regenerative hyperplasia, are commonly observed in patients with TS. The SHOX gene plays a crucial role in short stature and abnormal skeletal phenotype in patients with TS. Abnormal structure formation of the ureter and kidney is also common in patients with TS, and a non-mosaic 45,X karyotype is significantly associated with horseshoe kidneys. TS also affects brain structure and function. In this review, we explore various phenotypic and disease manifestations of TS in different organs, including the reproductive system, cardiovascular system, liver, kidneys, brain, and skeletal system.

Sex-linked genetic mechanisms and atrial fibrillation risk

Atrial fibrillation (AF) is a cardiac condition characterised by an irregular heartbeat, atrial pathology and an elevated downstream risk of thrombosis and heart failure, as well as neurological sequelae including stroke and dementia. The prevalence and presentation of, risk factors for, and therapeutic responses to, AF differ by sex, and this sex bias may be partially explained in terms of genetics. Here, we consider four sex-linked genetic mechanisms that may influence sex-biased phenotypes related to AF and provide examples of each: X-linked gene dosage, X-linked genomic imprinting, sex-biased autosomal gene expression, and male-limited Y-linked gene expression. We highlight novel candidate risk genes and pathways that warrant further investigation in clinical and preclinical studies. Understanding the biological basis of sex differences in AF should allow better prediction of disease risk, identification of novel risk/protective factors, and the development of more effective sex-tailored interventions.

Sex-Related Effects on Cardiac Development and Disease

Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality. Interestingly, male and female patients with CVD exhibit distinct epidemiological and pathophysiological characteristics, implying a potentially important role for primary and secondary sex determination factors in heart development, aging, disease and therapeutic responses. Here, we provide a concise review of the field and discuss current gaps in knowledge as a step towards elucidating the “sex determination–heart axis”. We specifically focus on cardiovascular manifestations of abnormal sex determination in humans, such as in Turner and Klinefelter syndromes, as well as on the differences in cardiac regenerative potential between species with plastic and non-plastic sexual phenotypes. Sex-biased cardiac repair mechanisms are also discussed with a focus on the role of the steroid hormone 17β-estradiol. Understanding the “sex determination–heart axis” may offer new therapeutic possibilities for enhanced cardiac regeneration and/or repair post-injury.

A Review of Recent Developments in Turner Syndrome Research

Turner syndrome is a rare disorder resulting from complete or partial loss of the second sex chromosome. Common manifestations include delayed growth, premature ovarian failure, congenital heart defects, endocrine disorders, lymphedema, and webbed neck. People with Turner syndrome have significantly increased mortality risk primarily due to cardiovascular abnormalities. The mechanisms that lead to these defects are not completely understood and are obscured by the significant variability of both karyotype and phenotype without consistent correlation between the two. This paper presents a review of the recent literature surrounding the symptoms, mechanisms, diagnosis, and treatment of Turner syndrome with a focus on cardiovascular manifestations. With technological advancements in genetics, the molecular processes of Turner syndrome have begun to be dissected. Certain genes on the X chromosome that typically escape inactivation have been implicated in both specific manifestations and broader risk categories. Recently identified genome-wide epigenetic changes may help explain the variability in presentation. It remains unclear as to how the combination of these factors results in the overall clinical picture, but advances in genomic, genetic, epigenetic, and -omics technology hold promise for providing insights that will improve the medical management of individuals with Turner syndrome.

The contribution of Xp22.31 gene dosage to Turner and Klinefelter syndromes and sex-biased phenotypes

Turner syndrome (TS) is a rare developmental condition in females caused by complete, or partial, loss of the second sex chromosome; it is associated with a number of phenotypes including short stature, ovarian failure and infertility, as well as neurobehavioural and cognitive manifestations. In contrast, Klinefelter syndrome (KS) arises from an excess of X chromosome material in males (typical karyotype is 47,XXY); like TS, KS is associated with infertility and hormonal imbalance, and behavioural/neurocognitive differences from gonadal sex-matched counterparts. Lower dosage of genes that escape X-inactivation may partially explain TS phenotypes, whilst overdosage of these genes may contribute towards KS-related symptoms. Here, I discuss new findings from individuals with deletions or duplications limited to Xp22.31 (a region escaping X-inactivation), and consider the extent to which altered gene dosage within this small interval (and of the steroid sulfatase (STS) gene in particular) may influence the phenotypic profiles of TS and KS. The expression of X-escapees can be higher in female than male tissues; I conclude by considering how lower Xp22.31 gene dosage in males may increase their likelihood of exhibiting particular phenotypes relative to females. Understanding the genetic contribution to specific phenotypes in rare disorders such as TS and KS, and to more common sex-biased phenotypes, will be important for developing more effective, and more personalised, therapeutic approaches.

Massive pericardial effusion and cardiac tamponade revealed undiagnosed Turner syndrome: a case report

Background

Patients with Turner syndrome (TS) are prone to autoimmune disorders. Although most patients with TS are diagnosed at younger ages, delayed diagnosis is not rare.

Case presentation

A 31-year-old woman was presented with facial edema, chest tightness and dyspnea. She had primary amenorrhea. Physical examination revealed short stature, dry skin and coarse hair. Periorbital edema with puffy eyelids were also noticed with mild goiter. Bilateral cardiac enlargement, distant heart sounds and pulsus paradoxus, in combination with hepatomegaly and jugular venous distention were observed. Her hircus and pubic hair was absent. The development of her breast was at 1st tanner period and gynecological examination revealed infantile vulva. Echocardiography suggested massive pericardial effusion. She was diagnosed with cardiac tamponade based on low systolic pressure, decreased pulse pressure and pulsus paradoxus. Pericardiocentesis was performed. Thyroid function test and thyroid ultrasound indicated Hashimoto’s thyroiditis and severe hypothyroidism. Sex hormone test revealed hypergonadotropin hypogonadism. Further karyotyping revealed a karyotype of 45, X [21]/46, X, i(X) (q10) [29] and she was diagnosed with mosaic + variant type of TS. L-T4 supplement, estrogen therapy, and antiosteoporosis treatment was initiated. Euthyroidism and complete resolution of the pericardial effusion was obtained within 2 months.

Conclusion

Hypothyroidism should be considered in the patients with pericardial effusion. The association between autoimmune thyroid diseases and TS should be kept in mind. Both congenital and acquired cardiovascular diseases should be screened in patients with TS.

Deficient knowledge in adult Turner syndrome care as an incentive to found Turner centers in Germany

OBJECTIVE

Turner syndrome (TS) is characterized by the complete or partial loss of the second sex chromosome and associated with a wide range of clinical manifestations. We aimed to assess the medical care of adult patients with TS in Germany.

DESIGN

Retrospective multicenter observational study.

METHODS

Data were collected from medical records of 258 women with TS treated between 2001 and 2017 in five non-university endocrinologic centers in Germany.

RESULTS

Mean age was 29.8 ± 11.6 years, mean height 152 ± 7.7 cm, and mean BMI 26.6 ± 6.3 kg/m2. The karyotype was known in 50% of patients. Information on cholesterol state, liver enzymes, and thyroid status was available in 81-98% of women with TS; autoimmune thyroiditis was diagnosed in 37%. Echocardiography was performed in 42% and cardiac MRI in 8.5%, resulting in a diagnosis of cardiovascular disorder in 28%. Data on growth hormone therapy were available for 40 patients (15%) and data concerning menarche in 157 patients (61%).

CONCLUSION

In 258 women with TS, retrospective analysis of healthcare data indicated that medical management was focused on endocrine manifestations. Further significant clinical features including cardiovascular disease, renal malformation, liver involvement, autoimmune diseases, hearing loss, and osteoporosis were only marginally if at all considered. Based on this evaluation and in accordance with recent guidelines, we compiled a documentation form facilitating the transition from pediatric to adult care and further medical management of TS patients. The foundation of Turner Centers in March 2019 will improve the treatment of TS women in Germany.