Correlations of phenotype and genotype in relation to morphologic remodelling of the aortic root in patients with Turner's syndrome

Cardiac abnormalities in girls with Turner syndrome: ECG abnormalities, myocardial strain imaging, and karyotype-phenotype associations

Turner syndrome (TS) is a chromosomal condition which is associated with an increased prevalence of cardiac morbidity and mortality. In this cross‐sectional study, Minnesota‐based electrocardiographic (ECG) abnormalities, aortic dimensions, routine‐ and myocardial strain echocardiographic parameters, and karyotype‐cardiac phenotype associations were assessed in girls with TS. In total, 101 girls with TS (0–18 years) were included. The prevalence of major ECG abnormalities was 2% (T‐wave abnormalities) and 39% had minor ECG abnormalities. Dilatation of the ascending aorta (z‐score > 2) was present in 16%, but the prevalence was much lower when using TS‐specific z‐scores. No left ventricular hypertrophy was detected and the age‐matched global longitudinal strain was reduced in only 6% of the patients. Cardiac abnormalities seemed more common in patients with a non‐mosaic 45,X karyotype compared with other karyotypes, although no statistically significant association was found. Lowering the frequency of echocardiography and ECG screening might be considered in girls with TS without cardiovascular malformations and/or risk factors for aortic dissection. Nevertheless, a large prospective study is needed to confirm our results. The appropriate z‐score for the assessment of aortic dilatation remains an important knowledge gap. The karyotype was not significantly associated with the presence of cardiac abnormalities, therefore cardiac screening should not depend on karyotype alone.

Phenotype in girls and women with Turner syndrome: Association between dysmorphic features, karyotype and cardio-aortic malformations

INTRODUCTION

Turner syndrome (TS) is a genetic disorder characterized by the (partial) absence or a structural aberration of the second sex chromosome and is associated with a variety of phenotypes with specific physical features and cardio-aortic malformations. The objective of this study was to gain a better insight into the differences in dysmorphic features between girls and women with TS and to explore the association between these features, karyotype and cardio-aortic malformations.

METHODS

This prospective study investigated 14 dysmorphic features of TS girls and women using a checklist. Three major phenotypic patterns were recognized (severe phenotype, lymphatic phenotype and skeletal phenotype). Patient data including karyotype and cardio-aortic malformations (bicuspid aortic valve (BAV) and aortic coarctation (COA)) were collected. Associations between the prevalence of dysmorphic features, karyotype and cardio-aortic malformations were analysed using chi²-test and odds ratios.

RESULTS

A total of 202 patients (84 girls and 118 women) were analysed prospectively. Differences in prevalence of dysmorphic features were found between girls and women. A strong association was found between monosomy 45,X and the phenotypic patterns. Furthermore, an association was found between COA and lymphatic phenotype, but no association was found between karyotype and cardio-aortic malformations.

CONCLUSION

This study uncovered a difference in dysmorphic features between girls and women. Monosomy 45,X is associated with a more severe phenotype, lymphatic phenotype and skeletal phenotype. All patients with TS should be screened for cardio-aortic malformations, because in contrast to previous reports, karyotype and cardio-aortic malformations showed no significant association.

Arterial hypertension in Turner syndrome: a review of the literature and a practical approach for diagnosis and treatment

Turner syndrome is a rare chromosomal disorder with complete or partial absence of one X chromosome that only occurs in women. Clinical presentation is variable, but congenital and acquired cardiovascular diseases are frequently associated diseases that add significantly to the increased morbidity and mortality in Turner syndrome patients. Arterial hypertension is reported in 13-58% of adult Turner syndrome patients and confers an increased risk for stroke and aortic dissection. Hypertension can be present from childhood on and is reported in one-quarter of the paediatric Turner syndrome patients. This article reviews the prevalence and cause of arterial hypertension in Turner syndrome and describes the relationship between blood pressure, aortic dilation and increased cardiovascular risk. We compare current treatment strategies and also propose an integrated practical approach for the diagnosis and treatment of hypertension in Turner syndrome applicable in daily practice.

Aortic dilatation in patients with Turner's syndrome without structural cardiac anomaly

INTRODUCTION

Dilatation of the ascending aorta is described in Turner's syndrome with variable prevalence (6.8-32%). Reported series typically include patients with associated cardiac anomalies.

OBJECTIVE

To characterise the prevalence, age of onset, and the progress of dilatation of the ascending aorta in Turner's syndrome patients free of structural cardiac anomalies. Potential risk factors such as karyotype and growth hormone therapy were analysed for correlation with aortic dilatation.

METHODS

We carried out a retrospective study with data collected from medical records and echocardiography studies. Patients with Tuner's syndrome followed-up between 1992 and 2010 with at least two echocardiography studies were eligible. Patients with previous cardiac surgery or under anti-hypertensive medication were excluded. Ascending aorta diameter measurements were adjusted for body surface area, and dilatation was defined as Z-score>2.

RESULTS

The study population consisted of 44 patients, aged 11.9±7.4 years at the first echocardiogram and 17.9±7.3 years at the last follow-up, with a follow-up duration of 6.0±3.7 years. A total of 13 (29.5%) patients exhibited aortic dilatation during follow-up, suggesting an actuarial estimate of the freedom from aortic dilatation dropping from 86 to 70% and then to 37% at 10, 20, and 30 years of age, respectively. There was no statistically significant impact of karyotype or growth hormone therapy on aortic Z-score progression.

CONCLUSION

The prevalence of dilatation of the ascending aorta in Turner's syndrome patients free of structural aortic anomalies is comparable with published data with associated lesions. Growth hormone therapy and karyotype had no significant impact; however, longitudinal follow-up is warranted.

Aortic dilatation and dissection in Turner syndrome: what we know, what we are unclear about and what we should do in clinical practice?

Aortic dilatation and aortic dissection are increasingly recognised in patients with Turner syndrome (TS). Risk factors for aortic dissection include aortic dilatation, bicuspid aortic valves, coarctation of aorta and pregnancy. The risk of death due to aortic dissection in pregnancy in TS is 2%, which is approximately 100 times higher than the general population, as maternal mortality is extremely low. Ongoing cardiovascular monitoring is recommended, although there remain several unanswered questions in relation to cardiovascular imaging especially the choice of modality for detection of vascular, valvular abnormalities and measurements of aortic dimensions. Due to the relative short stature of patients with TS, aortic dimensions need to be defined by aortic measurements adjusted for body surface area, known as aortic sized index (ASI). The relationship of ASI and other risk factors with aortic dissection is only beginning to be clarified. Clinical management and monitoring of such patients should be delivered by a group of clinicians familiar with the issues unique to TS patients in a multidisciplinary fashion. All clinicians including the non-specialists need to have a low threshold of suspecting aortic dissection in these adolescents and young adults. This up to date review, including a summary of all 122 published cases of TS patients with aortic dissection, aims to provide a summary of recent publications on characteristics of aortic dissection and aortic dilatation in TS to highlight gaps in knowledge and propose possible clinical monitoring pathway of cardiovascular health in children and adults with TS. Cardiovascular assessment and risk counselling is especially crucial during the period of transition of adolescents with TS, although life long monitoring by expert cognizant to the issues specific in TS is essential.

Cardiovascular pathology in males and females with 45,X/46,XY mosaicism

CONTEXT

The phenotype of 45,X/46,XY mosaicism is heterogeneous ranging from females with Turner syndrome (TS) to apparently normal males. Males with 45,X/46,XY frequently show stigmata typically associated with TS. We hypothesised that males with 45,X/46,XY have similar cardiovascular pathology as females with 45,X/46,XY.

OBJECTIVE

To investigate cardiovascular abnormalities in 45,X/46,XY males and to compare them with 45,X/46,XY females.

DESIGN

Patients with 45,X/46,XY mosaicism were selected from the Belgian Registry for Growth and Puberty problems and via the multidisciplinary clinic for disorders of sexual development.

PATIENTS

EIGHTEEN PATIENTS WERE INCLUDED: 8 raised as females (F) and 10 as males (M).

INTERVENTION

Complete cardiac examination with blood pressure measurement, ECG, echocardiography and MRI.

MAIN OUTCOME MEASUREMENT

Cardiac parameters were registered for both groups. In a second phase, clinical features and external masculinisation score (EMS) were retrospectively collected from the medical files.

RESULTS

A structural heart defect was diagnosed before inclusion in 1 F with coarctation and 1 M with spontaneously closed VSD. A bicuspid aortic valve was found in 8 (3 F, 5 M). Dilation of the ascending aorta was present in 4 M and was severe in 2 young boys. QTc was prolonged in 3 F and 2 M.

CONCLUSION

Males with 45,X/46,XY mosaicism have similar cardiovascular pathology as 45,X/46,XY females. Dilation of the ascending aorta can be important, also in males. We advise cardiac screening and life-long monitoring in all males with 45,X/46,XY mosaicism according to the existing guidelines for Turner syndrome.

Cardiovascular phenotype in Turner syndrome--integrating cardiology, genetics, and endocrinology

Cardiovascular disease is emerging as a cardinal trait of Turner syndrome, being responsible for half of the 3-fold excess mortality. Turner syndrome has been proposed as an independent risk marker for cardiovascular disease that manifests as congenital heart disease, aortic dilation and dissection, valvular heart disease, hypertension, thromboembolism, myocardial infarction, and stroke. Risk stratification is unfortunately not straightforward because risk markers derived from the general population inadequately identify the subset of females with Turner syndrome who will suffer events. A high prevalence of endocrine disorders adds to the complexity, exacerbating cardiovascular prognosis. Mounting knowledge about the prevalence and interplay of cardiovascular and endocrine disease in Turner syndrome is paralleled by improved understanding of the genetics of the X-chromosome in both normal health and disease. At present in Turner syndrome, this is most advanced for the SHOX gene, which partly explains the growth deficit. This review provides an up-to-date condensation of current state-of-the-art knowledge in Turner syndrome, the main focus being cardiovascular morbidity and mortality. The aim is to provide insight into pathogenesis of Turner syndrome with perspectives to advances in the understanding of genetics of the X-chromosome. The review also incorporates important endocrine features, in order to comprehensively explain the cardiovascular phenotype and to highlight how raised attention to endocrinology and genetics is important in the identification and modification of cardiovascular risk.

Abnormalities of the major intrathoracic arteries in Turner syndrome as revealed by magnetic resonance imaging

BACKGROUND

Ectatic aortopathy and arterial abnormalities cause excess morbidity and mortality in Turner syndrome, where a state of vasculopathy seemingly extends into the major head and neck branch arteries.

OBJECTIVE

We investigated the prevalence of abnormalities of the major intrathoracic arteries, their interaction with arterial dimensions, and their association with karyotype.

DESIGN

Magnetic resonance imaging scans determined the arterial abnormalities as well as head and neck branch artery and aortic dimensions in 99 adult women with Turner syndrome compared with 33 healthy female controls. Echocardiography determined aortic valve morphology.

RESULTS

In Turner syndrome, the relative risk of any congenital abnormality was 7.7 (p = 0.003) and 6.7 of ascending aortic dilation (p = 0.02). A bovine aortic arch was seen in both Turner syndrome and controls. Other abnormalities were only encountered in Turner syndrome: elongated transverse aortic arch (47%), bicuspid aortic valve (27%), aortic coarctation (13%), aberrant right subclavian artery (8%), and aortic arch hypoplasia (2%). The innominate and left common carotid arteries were enlarged in Turner syndrome (p < 0.001). Significant associations were first, bicuspid aortic valve with aortic coarctation, elongated transverse aortic arch, and ascending aortic dilation; second, aortic coarctation with elongated aortic arch and descending aortic dilation; third, 45,X with aortic coarctation, elongated transverse aortic arch and ascending aortic dilation; and fourth, branch artery dilation with bicuspid aortic valve, aortic coarctation, elongated transverse aortic arch and 45,X.

CONCLUSION

An increased risk of arterial abnormalities, aortic dilation, and enlargement of the branch arteries was found in Turner syndrome without distinct patterns of co-segregation.

Cardiovascular Disorders of Turner's Syndrome: A Review

A series of cardiovascular abnormalities may be associated with Turner's Syndrome (TS). Over 50% of the reported cardiovascular malformations have been bicuspid aortic valve or coarctation of the aorta alone. or in a combination, which may lead to a higher risk for infective endocarditis. Isolated dilation of the ascending aorta was often seen in TS, while aortic dissection has been increasingly observed in recent years. The aortic root dilation was found more likely to be due to a mesenchymal defect rather than atherosclerotic changes. Women with TS are often hypertensive as a result of aortic abnormality or renal vascular disorder. They have an increased risk of developing neoplasms, such as gonadoblastoma and dysgerminoma, and therefore they may require regular monitoring while receiving hormone therapy. In patients with gonadal dysgenesis, exogenous estrogen treatment poses a problem of connective tissue disorders of the great vessels. To resolve the contradiction between exogenous estrogen therapies and the hold-up of the progression of the connective tissue abnormality is a topic to be coped with. Careful clinical assessment is mandatory in the evaluation of patients with TS with cardiovascular abnormalities.