The deep biology of cognition: Moving toward a comprehensive neurodevelopmental model of Turner syndrome

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.

Reduced effects of social feedback on learning in Turner syndrome

Turner syndrome is a genetic condition caused by a complete or partial loss of one of the X chromosomes. Previous studies indicate that Turner syndrome is associated with challenges in social skills, but the underlying mechanisms remain largely unexplored. A possible mechanism is a reduced social influence on learning. The current study examined the impact of social and non-social feedback on learning in women with Turner syndrome (n = 35) and a sex- and age-matched control group (n = 37). Participants were instructed to earn points by repeatedly choosing between two stimuli with unequal probabilities of resulting in a reward. Mastering the task therefore required participants to learn through feedback which of the two stimuli was more likely to be rewarded. Data were analyzed using computational modeling and analyses of choice behavior. Social feedback led to a more explorative choice behavior in the control group, resulting in reduced learning compared to non-social feedback. No effects of social feedback on learning were found in Turner syndrome. The current study thus indicates that women with Turner syndrome may be less sensitive to social influences on reinforcement learning, than the general population.

Improving Anxiety Screening in Patients with Turner Syndrome

INTRODUCTION

Turner syndrome (TS) results from a complete or partial loss of the X chromosome and affects 25-50 per 100,000 females. These individuals have characteristic neurocognitive and psychological profiles with an increased lifetime prevalence of mood disorders, such as depression and anxiety. Consensus guidelines recommend the use of psychometrically robust tools to screen for these conditions [Eur J Endocrinol. 2017;177(3):G1-G70 and Gynecol Endocrinol. 2004;19(6):313-9]. We propose a sustainable and informative approach to routine anxiety screening in individuals with TS and describe the prevalence of anxiety, genotype-phenotype associations, and impact of comorbidities on anxiety.

METHODS

We pilot the use of a self-administered version of the validated Pediatric, Parent Proxy, and Adult Patient-Reported Outcomes Measurement Information System (PROMIS®) Anxiety tool during routine visits to the Cincinnati Children's Hospital Medical Center (CCHMC) TS clinic from October 2019 to March 2020.

RESULTS

Ninety-two eligible TS females, ages 8-62 years, received the PROMIS® Anxiety measure. Elevated anxiety scores, ≥1 standard deviation above the T-score mean, were present in 65% of patients (38% mild, 19% moderate, and 8% severe). Results were discussed during the clinic visit, and referral for further evaluation and treatment was offered. There was no apparent genotype-phenotype association among females with anxiety; however, there appeared to be elevated anxiety symptoms (T-score >60) in those with hearing deficits and also in individuals with three or more medical comorbidities. Of the 55% of patients who filled out the acceptability survey, 88% found the process helpful and ∼50% felt that screening should be performed at least every 6 months.

CONCLUSION

Our study demonstrated a high prevalence of anxiety symptoms within a cohort of 92 females with TS. In alignment with current guidelines, these findings indicate the importance of routine neuropsychological assessments for timely recognition and subsequent management of anxiety, especially as milder presentations may otherwise go unnoticed. We have shown that screening tools, such as the PROMIS® Anxiety measure, can be easily utilized by nonmental health care providers (i.e., endocrinologists) who may see TS patients more frequently and be able to initiate impactful discussions surrounding mental health and further referral to subspecialists for expert management.

The Hypothesis of the Prolonged Cell Cycle in Turner Syndrome

Turner syndrome (TS) is a chromosomal disorder that is caused by a missing or structurally abnormal second sex chromosome. Subjects with TS are at an increased risk of developing intrauterine growth retardation, low birth weight, short stature, congenital heart diseases, infertility, obesity, dyslipidemia, hypertension, insulin resistance, type 2 diabetes mellitus, metabolic syndrome, and cardiovascular diseases (stroke and myocardial infarction). The underlying pathogenetic mechanism of TS is unknown. The assumption that X chromosome-linked gene haploinsufficiency is associated with the TS phenotype is questioned since such genes have not been identified. Thus, other pathogenic mechanisms have been suggested to explain this phenotype. Morphogenesis encompasses a series of events that includes cell division, the production of migratory precursors and their progeny, differentiation, programmed cell death, and integration into organs and systems. The precise control of the growth and differentiation of cells is essential for normal development. The cell cycle frequency and the number of proliferating cells are essential in cell growth. 45,X cells have a failure to proliferate at a normal rate, leading to a decreased cell number in a given tissue during organogenesis. A convergence of data indicates an association between a prolonged cell cycle and the phenotypical features in Turner syndrome. This review aims to examine old and new findings concerning the relationship between a prolonged cell cycle and TS phenotype. These studies reveal a diversity of phenotypic features in TS that could be explained by reduced cell proliferation. The implications of this hypothesis for our understanding of the TS phenotype and its pathogenesis are discussed. It is not surprising that 45,X monosomy leads to cellular growth pathway dysregulation with profound deleterious effects on both embryonic and later stages of development. The prolonged cell cycle could represent the beginning of the pathogenesis of TS, leading to a series of phenotypic consequences in embryonic/fetal, neonatal, pediatric, adolescence, and adulthood life.

Acute Mania and Catatonia in a Teenager Successfully Treated with Electroconvulsive Therapy and Diagnosed with Turner Syndrome and Bipolar Disorder

Background

Turner syndrome (TS) is an X-linked chromosomal abnormality with a global prevalence of 1/2000 live-born girls. The physiological symptoms of TS have been thoroughly characterized, but only a few studies have described associated psychiatric symptoms. We report a case of an adolescent girl who presented with acute mania with psychotic features and was successfully treated with electroconvulsive therapy (ECT). She was subsequently diagnosed with bipolar syndrome and TS. Case Presentation. A 17-year-old girl presented to us with manic symptoms, including disorganized speech, auditory hallucinations, and affect lability. Initially, she was treated with antipsychotics and benzodiazepines, whereby the positive affective symptoms declined. However, the psychotic symptoms progressed, and she developed a catatonic state. ECT was started 6 days after admission, with improvement after two treatments. When ECT was tapered after seven sessions, she relapsed, and the treatment was extended to twelve sessions, with successful outcome. Following discharge, she was diagnosed with TS with partial loss on one of the X-chromosomes (46X, del (X)(p21)), which might have contributed to the development of her sudden acute manic episode.

Conclusions

This case demonstrates for the first time that ECT may be a safe and efficient treatment strategy for acute mania in adolescents with concomitant TS and that severely affected adolescents may require a prolonged series with gradual tapering of ECT. The present case also demonstrates a possible association between TS and bipolar syndrome and that the clinical presentation of a manic episode in a patient with this comorbidity could be more complex and the treatment response slower.

Neurodevelopmental and psychiatric disorders in females with Turner syndrome: a population-based study

Background

Turner syndrome is the result of the partial or complete absence of an X chromosome in phenotypic girls. This can cause an array of medical and developmental difficulties. The intelligence quotient in females with Turner syndrome has previously been described as uneven, but considered within normal range. Although their social, intellectual, and psychiatric profile is described, it is unclear to what extent these females meet the clinical criteria for neurodevelopmental or psychiatric diagnoses. The aim of this study was to examine the prevalence of neurodevelopmental and psychiatric disorders in females with Turner syndrome.

Methods

A retrospective cohort study was performed with a total of 1392 females with Turner syndrome identified through the Swedish National Patient Register and compared with 1:100 age- and sex-matched controls from the general population. The associations between Turner syndrome and diagnoses of neurodevelopmental and/or psychiatric disorders were calculated using conditional logistic regression and is presented as estimated risk (odds ratio, OR, 95% confidence interval, CI) in females with Turner syndrome compared with matched controls.

Results

Females with Turner syndrome had a higher risk of neurodevelopmental or psychiatric disorder (OR 1.37, 95% CI 1.20–1.57), an eightfold increased risk of intellectual disability (OR 8.59, 95% CI 6.58–11.20), and a fourfold increased risk of autism spectrum disorder (OR 4.26, 95% CI 2.94‑6.18) compared with the controls. In addition, females with Turner syndrome had twice the risk of a diagnosis of schizophrenia and related disorders (OR 1.98, 95% CI 1.36–2.88), eating disorders (OR 2.03, 95% CI 1.42–2.91), and behavioral and emotional disorders with onset in childhood (OR 2.01, 95% CI 1.35–2.99).

Conclusions

Females with Turner syndrome have an increased risk of receiving a diagnosis of neurodevelopmental or psychiatric disorder. This warrants extensive assessment of intellectual and cognitive functions from early age, and increased psychiatric vigilance should be a part of lifelong healthcare for females 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.

The state of Turner syndrome science: Are we on the threshold of discovery?

Turner syndrome (TS), a genetic condition affecting roughly 1 in 2,000 females, is caused by a complete or partial loss of the second sex chromosome. This special issue of the American Journal of Medical Genetics Part C is a collection of research and clinical care reviews in TS from an international group of physician and scientist leaders who attended the 2018 "Turner Network Resource Symposium: Turner Science in the 21st Century", held in Arlington Virginia, July 15th-17th, 2018. Both this special issue and the 2018 Symposium are fueled by two rationales. First, inadequate attention has been given to health and psychosocial problems in girls and women with TS; and second, that an understanding of TS might shed light on the role of sex chromosome dosage in common conditions such as heart disease and autoimmune disease. These seminars interweave multiple themes: the fundamental partnership between participants with rare diseases and researchers, new knowledge regarding clinical care in TS, and an understanding of the "molecular phenotype" of TS-associated conditions.

Clinical developmental, neuropsychological, and social-emotional features of Turner syndrome

Individuals with Turner syndrome (TS) are at risk for a constellation of neurocognitive and psychosocial differences, although there is significant individual variability in these features. TS is associated with an increased risk for difficulties with visual-spatial reasoning, visual-spatial memory, attention, executive functioning, motor, and math skills. Additionally, increased rates of social difficulties, anxiety, and depression are observed. There can be significant interplay between all of these factors contributing to the behavioral phenotype. Neuropsychological features and previous research are reviewed. Clinical considerations and recommendations for evaluation and treatment of psychological and behavioral difficulties are provided, including consideration of medical features in TS, as well as therapies, educational supports, and medication treatment. Future research is needed to evaluate effectiveness of different treatments for neuropsychological and psychosocial features of TS, including modification and validation of existing evidence-based treatments and new approaches to care.