Turner Syndrome: An Update

Exploring the impact of a KCNH2 missense variant on Long QT syndrome: insights into a novel gender-selective, incomplete penetrance inheritance mode

Background

Long QT syndrome (LQTS) is an inherited malignant arrhythmia syndrome that poses a risk of sudden death. Variants in the Potassium Voltage-Gated Channel Subfamily H Member 2 (KCNH2) gene are known to cause Long QT syndrome through an autosomal dominant inheritance pattern. However, as of now, there have been no reports of any KCNH2 variant leading to Long QT syndrome exhibiting incomplete penetrance that is influenced by gender.

Methods

Whole-exome sequencing (WES) was conducted on the proband to identify pathogenic variants. Subsequently, Sanger sequencing was employed to validate the identified likely pathogenic variants in all family members.

Results

We analyzed a pedigree spanning three-generations afflicted by Long QT syndrome. WES revealed a novel KCNH2 missense variant (p.Val630Gly, c.1889 T>G) as the causative factor for the family's phenotype. Within this family, all three male carriers of the KCNH2 variant carriers exhibited the Long QT syndrome phenotype: one experienced sudden death during sleep, another received an implantable cardioverter defibrillator (ICD), and a younger man displayed a prolonged QTc interval without any instances of syncope or malignant arrhythmia to date. Interestingly, the middle-aged female carrier showed no Long QT Syndrome phenotype. However, her offspring, diagnosed with Turner syndrome (45, X) and also a carrier of this variant, experienced frequent syncope starting at 12 years old and was diagnosed with Long QT syndrome, leading to an ICD implantation when she was 15 years old. These observations suggest that the manifestation of Long QT syndrome associated with this KCNH2 variant exhibits incomplete penetrance influenced by gender within this family, indicating potential protective mechanisms against the syndrome in females affected by this variant.

Conclusion

Our investigation has led to the identification of a novel pathogenic KCNH2 variant responsible for Long QT syndrome within a familial context characterized by gender-selective, incomplete penetrance. This discovery highlights a unique pathogenic inheritance pattern for the KCNH2 gene associated with Long QT syndrome, and could potentially shed light on the distinct penetrance behaviors and patterns of the KCNH2 gene. This discovery broadens our exploration of the KCNH2 gene in cardiac arrhythmias, highlighting the intricate genetic dynamics behind Long QT syndrome.

Cardiovascular Disease and Inpatient Complications in Turner Syndrome: A Propensity Score Analysis

BACKGROUND

Turner syndrome is a genetic disorder that occurs in female individuals and is characterized by the absence of 1 of the X chromosomes. This study examined the risk of cardiovascular disease and inpatient clinical outcomes in patients with Turner syndrome.

METHODS

Data were extracted from the Nationwide Inpatient Sample 2016 database. Propensity score analysis was used to match women with Turner syndrome and women without Turner syndrome admitted to a hospital in the same year to evaluate the risk of cardiovascular disease and inpatient clinical outcomes in patients with Turner syndrome.

RESULTS

After 1:1 matching, 710 women with Turner syndrome and 710 women without Turner syndrome were included in the final analysis. Compared with women without Turner syndrome, women with Turner syndrome were more likely to have a bicuspid aortic valve (9.4% vs 0.01%; P < .01), coarctation of the aorta (5.8% vs 0.3%; P < .01), atrial septal defect (6.1% vs 0.8%; P < .01), and patent ductus arteriosus (4.6% vs 0.6%; P < .01). Patients with Turner syndrome were more likely to have an aortic aneurysm (odds ratio [OR], 2.46 [95% CI, 1.02-5.98]; P = .046), ischemic heart disease (OR, 1.66 [95% CI, 1.10-2.5]; P = .02), heart failure (OR, 3.15 [95% CI, 1.99-4.99]; P < .01), and atrial fibrillation or flutter (OR, 2.48 [95% CI, 1.42-4.34]; P < .01). Patients with Turner syndrome were more likely to have pulmonary arterial hypertension (OR, 2.12 [95% CI, 1.08-4.14]; P = .03) and acute kidney injury (OR, 1.60 [95% CI, 1.06-2.42]; P = .03) and to require mechanical ventilation (OR, 1.66 [95% CI, 1.04-2.68]; P = .04).

CONCLUSION

Turner syndrome is associated with an increased rate of cardiovascular disease and inpatient complications. These findings suggest that patients with Turner syndrome should be screened and monitored closely for cardiovascular disease and inpatient complications.

Are Young People with Turner Syndrome Who Have Undergone Treatment with Growth and Sex Hormones at Higher Risk of Metabolic Syndrome and Its Complications?

INTRODUCTION

Metabolic syndrome (MetS), characterized by visceral obesity, glucose abnormalities, hypertension and dyslipidemia, poses a significant risk of diabetes and cardiovascular disease. Turner syndrome (TS), resulting from X chromosome abnormalities, carries health complications. Despite growing evidence of an increased risk of MetS in women with TS, its prevalence and risk factors remain under investigation. These considerations are further complicated by the varying timing and dosages of treatment with growth hormone and sex hormones.

METHODS

We conducted a cross-sectional study comparing 44 individuals with TS with 52 age-matched control subjects. Growth hormone treatment in the study group was administered for varying lengths of time, depending on clinical response. We collected anthropometric, metabolic, endocrine and body composition data. Statistical analyses included logistic regression.

RESULTS

Baseline characteristics, including age, BMI and height, were comparable between the TS and control groups. Hormonally, individuals with TS showed lower levels of testosterone, DHEA-S, and cortisol, as well as elevated FSH. Lipid profiles indicated an atherogenic profile, and the body composition analysis showed increased visceral adipose tissue in those with TS. Other metabolic abnormalities were common in individuals with TS too, including hypertension and impaired fasting glucose levels. The risk of MetS components was assessed in subgroups according to karyotypes: monosomy 45X0 vs. other mosaic karyotypes. Logistic regression analysis showed a significant association between increased visceral adipose tissue in subjects with TS. Those with metabolic complications tended to have less muscle strength compared to those without these complications in both the study and control groups.

CONCLUSIONS

This study highlights the unique metabolic and cardiovascular risk profile of individuals with TS, characterized by atherogenic lipids, higher levels of visceral adipose tissue and increased metabolic abnormalities. These findings underscore the importance of monitoring metabolic health in individuals with TS, regardless of age, BMI or karyotype, and suggest the potential benefits of lifestyle modification, building more muscle strength, and weight control strategies. Further research is needed to better understand and address the metabolic challenges faced by women with TS.

Chromosome analysis of foetal tissue from 1903 spontaneous abortion patients in 5 regions of China: a retrospective multicentre study

BACKGROUND

Abnormal foetal tissue chromosome karyotypes are one of the important pathogenic factors for spontaneous abortion (SA). To investigate the age and abnormal foetal karyotypes of 1903 couples who experienced SA.

METHODS

A retrospective multicentre study collected age and foetal tissue karyotypes CNV-seq data of 1903 SA couples from 6 hospitals in 5 regions from January 2017 to March 2022. The distribution and correlation of abnormal foetal tissue karyotypes were evaluated by using regions and age.

RESULTS

In our study, 1140 couples (60.5% of the total) had abnormal foetal tissue chromosome karyotypes in all regions. We found that there were differences in the number of abnormal foetal tissue chromosome karyotypes, of which the incidence of trisomy was higher. At the same time, the populations situated in the eastern region had a more triploid (15.5%) distribution, trisomy (58.1%) in the southern region, mosaicism (14.8%) and microduplication (31.7%) in the southwestern region, microdeletion (16.7%) in the northern region. There are variances across areas, and it is more common in the north. The incidence risk of prenatal chromosomal abnormalities varied according to age group.

CONCLUSION

The findings of this study suggest that the karyotypes of patients with abnormal foetal tissue chromosome abortion in different regions were different. Meanwhile, patients ≥ 35 years old had a higher risk of abnormal foetal tissue chromosome abortion.

The Interplay between Muscular Grip Strength and Bone Mineral Density with Consideration of Metabolic and Endocrine Parameters in Individuals with Turner Syndrome

INTRODUCTION

Patients with Turner syndrome (TS) often face skeletal and muscular challenges, including reduced bone mineral density (BMD) and muscle weakness. This comprehensive study sheds light on the complex interplay between muscle strength, BMD, and metabolic and endocrine parameters in TS and healthy subjects.

METHODS

A cross-sectional study involving 42 TS patients and 70 healthy women was conducted. All patients had their BMD determined in the L1-L4 lumbar spine section and in the whole skeleton as well as the parameters of body fat mass (BF), and visceral fat mass (VF) were also determined. The maximum gripping force was measured with a hydraulic manual dynamometer. In addition, a number of blood hormonal and metabolic parameters were determined.

RESULTS

In the TS group, hand grip strength correlated positively with triglyceride levels but not with BMD. Healthy individuals had a positive link between hand grip strength and BMD, while patients with TS did not show a significant association between the two. A trend suggested that longer recombinant human growth hormone (rhGH) therapy might improve BMD in the L1-L4 region. Multiple linear regression analysis revealed that muscle strength assessment may be a potential exponent of reduced BMD, and also used clinically in young adult women but not in individuals with TS.

CONCLUSIONS

The relationship between BMD variables and hand grip might differ between the two groups, potentially indicating distinct musculoskeletal characteristics in TS patients. Longer rhGH therapy in TS patients may have a positive effect on BMD in the L1-L4 region. Understanding the intricate relationships between these factors is important for optimizing clinical management strategies and improving the quality of life for TS patients.

Analysis of genetic variability in Turner syndrome linked to long-term clinical features

Background

Women with Turner syndrome (TS) (45,X and related karyotypes) have an increased prevalence of conditions such as diabetes mellitus, obesity, hypothyroidism, autoimmunity, hypertension, and congenital cardiovascular anomalies (CCA). Whilst the risk of developing these co-morbidities may be partly related to haploinsufficiency of key genes on the X chromosome, other mechanisms may be involved. Improving our understanding of underlying processes is important to develop personalized approaches to management.

Objective

We investigated whether: 1) global genetic variability differs in women with TS, which might contribute to co-morbidities; 2) common variants in X genes - on the background of haploinsufficiency - are associated with phenotype (a "two-hit" hypothesis); 3) the previously reported association of autosomal TIMP3 variants with CCA can be replicated.

Methods

Whole exome sequencing was undertaken in leukocyte DNA from 134 adult women with TS and compared to 46,XX controls (n=23), 46,XX women with primary ovarian insufficiency (n=101), and 46,XY controls (n=11). 1) Variability in autosomal and X chromosome genes was analyzed for all individuals; 2) the relation between common X chromosome variants and the long-term phenotypes listed above was investigated in a subgroup of women with monosomy X; 3) TIMP3 variance was investigated in relation to CCA.

Results

Standard filtering identified 6,457,085 autosomal variants and 126,335 X chromosome variants for the entire cohort, whereas a somatic variant pipeline identified 16,223 autosomal and 477 X chromosome changes. 1) Overall exome variability of autosomal genes was similar in women with TS and control/comparison groups, whereas X chromosome variants were proportionate to the complement of X chromosome material; 2) when adjusted for multiple comparisons, no X chromosome gene/variants were strongly enriched in monosomy X women with key phenotypes compared to monosomy X women without these conditions, although several variants of interest emerged; 3) an association between TIMP3 22:32857305:C-T and CCA was found (CCA 13.6%; non-CCA 3.4%, p<0.02).

Conclusions

Women with TS do not have an excess of genetic variability in exome analysis. No obvious X-chromosome variants driving phenotype were found, but several possible genes/variants of interest emerged. A reported association between autosomal TIMP3 variance and congenital cardiac anomalies was replicated.

Effect of Growth Hormone and Estrogen Replacement Therapy on Bone Mineral Density in Women with Turner Syndrome: A Meta-Analysis and Systematic Review

Osteoporosis is a serious implication of Turner syndrome (TS). Common methods for the treatment of TS are growth hormone (GHT) and estrogen replacement therapy (ERT). We examined the relationship between the treatment of TS and bone mineral density (BMD) of the lumbar spine. The purpose of our study was to show the currency of BMD states among patients with TS for treatment with GHT and ERT. We searched databases for studies published from inception to April 2023. The articles were related to TS, osteoporosis, ERT, GHT, BMD and treatment patients with TS. We applied the selection criteria: lumbar spine values at L1-L4; dual-energy X-ray absorptiometry (DXA); treatment which was applied: one group of articles: ERT and two group of articles: GHT; results performed as means ± SD. In total, 79 articles were analyzed, of which 20 studies were included and 5 were considered for meta-analysis. The total number of women in the articles selected was 71. Based on the results of the meta-analysis, the effect of ERT on BMD demonstrated a significant increase in BMD (the standardized mean difference in the random model was 0.593 g/cm2, 95% CI: 0.0705 to 1.116; p = 0.026), which showed that treatment with estrogen particularly increases bone mass during treatment, which contributes to reducing the risk of fractures. The effect of GHT on BMD demonstrated a non-significant decrease in BMD in patients with TS. The results for growth hormone show that this therapy does not improve bone density. However, our review emphasizes the beneficial effect of supplementing growth hormone (GH) on the clinical presentation of TS.

Incidence of sex chromosome aneuploidy in a prenatal population: 27-year longitudinal study in Northern Italy

OBJECTIVES

The availability of cell-free (cf) DNA as a prenatal screening tool affords an opportunity for non-invasive identification of sex chromosome aneuploidy (SCA). The aims of this longitudinal study were to investigate the evolution and frequency of both invasive prenatal diagnostic testing, using amniocentesis and chorionic villus sampling (CVS), and the detection of SCA in cfDNA samples from a large unselected cohort in Northern Italy.

METHODS

The results of genetic testing from CVS and amniotic fluid samples received from public and private centers in Italy from 1995 to 2021 were collected. Chromosomal analysis was performed by routine Q-banding karyotype. Regression analyses and descriptive statistics were used to determine population data trends regarding the frequency of prenatal diagnostic testing and the identification of SCA, and these were compared with the changes in indication for prenatal diagnostic tests and available screening options.

RESULTS

Over a period of 27 years, there were 13 939 526 recorded births and 231 227 invasive procedures were performed, resulting in the prenatal diagnosis of 933 SCAs. After the commercial introduction of cfDNA use in 2015, the frequency of invasive procedures decreased significantly (P = 0.03), while the frequency of prenatal SCA detection increased significantly (P = 0.007). Between 2016 and 2021, a high-risk cfDNA result was the indication for 31.4% of detected sex chromosome trisomies, second only to advanced maternal age.

CONCLUSIONS

Our findings suggest that the inclusion of SCA in prenatal cfDNA screening tests can increase the prenatal diagnosis of affected individuals. As the benefits of early ascertainment are increasingly recognized, it is essential that healthcare providers are equipped with comprehensive and evidence-based information regarding the associated phenotypic differences and the availability of targeted effective interventions to improve neurodevelopmental and health outcomes for affected individuals. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Components of the metabolic syndrome in girls with Turner syndrome treated with growth hormone in a long term prospective study

Background

Components of the metabolic syndrome are more common in patients with Turner syndrome (TS) than in the general population. Long-term growth hormone (GH) treatment also affects the parameters of carbohydrate metabolism. Therefore, all these factors should be monitored in girls with TS.

Objective

To assess the occurrence of metabolic syndrome components in TS girls before GH treatment and to monitor changes in metabolic parameters throughout GH therapy.

Patients and method

89 TS patients were enrolled in the study. Clinical and laboratory data after the 1st (V1), 3rd (V3), 5th (V5) and 10th (V10) year of GH therapy was available respectively in 60, 76, 50 and 22 patients. The patients' biochemical phenotypes were determined by glucose 0', 120', insulin 0', 120', HOMA-IR, Ins/Glu ratio, HDL-cholesterol and triglycerides (TG) concentration.

Results

Obesity was found during V0 in 7.9% of patients,V1 - 5%, V3 - 3.9%, V5 - 2%, V10 - 0%. No patient met diagnostic criteria for diabetes. A significant increase in the basal plasma glucose 0' was found in the first five years of therapy (pV0-V1 < 0.001; pV0-V3 = 0.006; pV0-V5 < 0.001). V10 glucose 120' values were significantly lower than at the onset of GH treatment (pV0-V10 = 0.046). The serum insulin 0' and 120' concentrations as well as insulin resistance increased during treatment. No statistically significant differences in serum TG and HDL-cholesterol levels during GH therapy were found.

Conclusion

The development of insulin resistance and carbohydrate metabolism impairment have the greatest manifestations during GH therapy in girls with TS. Monitoring the basic parameters of carbohydrate-lipid metabolism in girls with TS seems particularly important.