Genes that escape from X‐chromosome inactivation: Potential contributors to Klinefelter syndrome

Abstract STUDY QUESTION Does the X chromosome inactivation (XCI) of Klinefelter syndrome (KS)-derived human induced pluripotent stem cells (hiPSCs) correspond to female human pluripotent stem cells (hPSCs) and reflect the KS genotype? SUMMARY ANSWER Our results demonstrate for the first time that KS-derived hiPSCs show similar XCI behavior to female hPSCs in culture and show biological relevance to KS genotype-related clinical features. WHAT IS KNOWN ALREADY So far, assessment of XCI of KS-derived hiPSCs was based on H3K27me3 staining and X-inactive specific transcript gene expression disregarding the at least three XCI states (XaXi with XIST coating, XaXi lacking XIST coating, and XaXe (partially eroded XCI)) that female hPSCs display in culture. STUDY DESIGN, SIZE, DURATION The study used hiPSC lines generated from two azoospermic patients with KS and included two healthy male (HM) and one healthy female donor. PARTICIPANTS/MATERIALS, SETTING, METHODS In this study, we derived hiPSCs by reprograming fibroblasts with episomal plasmids and applying laminin 521 as culture substrate. hiPSCs were characterized by karyotyping, immunocytochemistry, immunohistochemistry, quantitative PCR, teratoma formation, and embryoid body differentiation. XCI and KS hiPSC relevance were assessed by whole genome transcriptomics analysis and immunocytochemistry plus FISH of KS, HM and female fibroblast, and their hiPSC derivatives. MAIN RESULTS AND THE ROLE OF CHANCE Applying whole genome transcriptomics analysis, we could identify differentially expressed genes (DEGs) between KS and HM donors with enrichment in gene ontology terms associated with fertility, cardiovascular development, ossification, and brain development, all associated with KS genotype-related clinical features. Furthermore, XCI analysis based on transcriptomics data, RNA FISH, and H3K27me3 staining revealed variable XCI states of KS hiPSCs similar to female hiPSCs, showing either normal (XaXi) or eroded (XaXe) XCI. KS hiPSCs with normal XCI showed nevertheless upregulated X-linked genes involved in nervous system development as well as synaptic transmission, supporting the potential use of KS-derived hiPSCs as an in vitro model for KS. LIMITATIONS, REASONS FOR CAUTION Detailed clinical information for patients included in this study was not available. Although a correlation between DEGs and the KS genotype could be observed, the biological relevance of these cells has to be confirmed with further experiments. In addition, karyotype analysis for two hiPSC lines was performed at passage 12 but not repeated at a later passage. Nevertheless, since all XCI experiments for those lines were performed between passage 11 and 15 the authors expect no karyotypic changes for those experiments. WIDER IMPLICATIONS OF THE FINDINGS As KS patients have variable clinical phenotypes that are influenced by the grade of aneuploidy, mosaicism, origin of the X chromosome, and XCI ‘escapee’ genes, which vary not only among individuals but also among different tissues within the same individual, differentiated KS hiPSCs could be used for a better understanding of KS pathogenesis. STUDY FUNDING/COMPETING INTEREST(S) This study was supported by grants from the Knut and Alice Wallenberg Foundation (2016.0121 and 2015.0096), Ming Wai Lau Centre for Reparative Medicine (2-343/2016), Ragnar Söderberg Foundation (M67/13), Swedish Research Council (2013-32485-100360-69), the Centre for Innovative Medicine (2–388/2016–40), Kronprinsessan Lovisas Förening För Barnasjukvård/Stiftelsen Axel Tielmans Minnesfond, Samariten Foundation, Jonasson Center at the Royal Institute of Technology, Sweden, and Initial Training Network Marie Curie Program ‘Growsperm’ (EU-FP7-PEOPLE-2013-ITN 603568). The authors declare no conflicts of interest.

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Intelligence Quotient Variability in Klinefelter Syndrome Is Associated With GTPBP6 Expression Under Regulation of X-Chromosome Inactivation Pattern

Frontiers in Genetics ◽

10.3389/fgene.2021.724625 ◽

2021 ◽

Vol 12 ◽

Author(s):

Luciane Simonetti ◽

Lucas G. A. Ferreira ◽

Angela Cristina Vidi ◽

Janaina Sena de Souza ◽

Ilda S. Kunii ◽

...

Keyword(s):

Gene Expression ◽

X Chromosome ◽

Intelligence Quotient ◽

Klinefelter Syndrome ◽

X Chromosome Inactivation ◽

X Inactivation ◽

Chromosome Inactivation ◽

Neurocognitive Dysfunction ◽

Inactivation Pattern ◽

Iq Scores

Klinefelter syndrome (KS) displays a broad dysmorphological, endocrinological, and neuropsychological clinical spectrum. We hypothesized that the neurocognitive dysfunction present in KS relies on an imbalance in X-chromosome gene expression. Thus, the X-chromosome inactivation (XCI) pattern and neurocognitive X-linked gene expression were tested and correlated with intelligence quotient (IQ) scores. We evaluated 11 KS patients by (a) IQ assessment, (b) analyzing the XCI patterns using both HUMARA and ZDHHC15 gene assays, and (c) blood RT-qPCR to investigate seven X-linked genes related to neurocognitive development (GTPBP6, EIF2S3, ITM2A, HUWE1, KDM5C, GDI1, and VAMP7) and XIST in comparison with 14 (male and female) controls. Considering IQ 80 as the standard minimum reference, we verified that the variability in IQ scores in KS patients seemed to be associated with the XCI pattern. Seven individuals in the KS group presented a random X-inactivation (RXI) and lower average IQ than the four individuals who presented a skewed X-inactivation (SXI) pattern. The evaluation of gene expression showed higher GTPBP6 expression in KS patients with RXI than in controls (p = 0.0059). Interestingly, the expression of GTPBP6 in KS patients with SXI did not differ from that observed in controls. Therefore, our data suggest for the first time that GTPBP6 expression is negatively associated with full-scale IQ under the regulation of the type of XCI pattern. The SXI pattern may regulate GTPBP6 expression, thereby dampening the impairment in cognitive performance and playing a role in intelligence variability in individuals with KS, which warrants further mechanistic investigations.

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Anthropometry in Klinefelter Syndrome - Multifactorial Influences Due to CAG Length, Testosterone Treatment and Possibly Intrauterine Hypogonadism

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.2014-2834 ◽

2015 ◽

Vol 100 (3) ◽

pp. E508-E517 ◽

Cited By ~ 49

Author(s):

Simon Chang ◽

Anne Skakkebæk ◽

Christian Trolle ◽

Anders Bojesen ◽

Jens Michael Hertz ◽

...

Keyword(s):

Body Composition ◽

X Chromosome ◽

Fat Mass ◽

Klinefelter Syndrome ◽

X Chromosome Inactivation ◽

Repeat Length ◽

Cag Repeat ◽

Chromosome Inactivation ◽

Parental Origin ◽

Skewed X Chromosome Inactivation

Context: Klinefelter syndrome, 47, XXY (KS), is underdiagnosed partly due to few clinical signs complicating identification of affected individuals. Certain phenotypic traits are common in KS. However, not all aspects of the KS phenotype are well described. Objective: To describe anthropometry and body composition in KS and relate findings to biochemistry and X-chromosome related genetic markers. Design, Setting and Participants: Seventy three KS males referred to our clinic and 73 age-matched controls underwent comprehensive measurements of anthropometry and body composition in a cross-sectional, case-controlled study. Furthermore, genetic analysis for parental origin of the supernumerary X-chromosome, skewed X-chromosome inactivation and androgen receptor (AR) CAG repeat length was done. Main Outcome Measure: Anthropometry and body composition in KS and the effect of genotype hereon. Results: KS males were taller (absolute difference: 5.1 cm, P < .001) with longer legs (5.7 cm, P < .001) compared with controls. Furthermore, 2D:4D was increased in KS males (relative effect size: Cohen's d = 0.40), reflecting reduced fetal testosterone exposure. Also, bi-iliac width (0.41), waist (0.52), and hip circumference (0.47) (P < .02 for all), as well as total fat mass (0.74), abdominal fat mass (0.67), and total body fat percentage (0.84) was increased in KS males (P < .001 for all), while bitesticular volume was reduced (4.6). AR CAG repeat length was comparable in KS and controls, and among KS CAG correlated to arm length (P = .04), arm span (P = .01), and leg length (P = .04). Effects of parental origin of the supernumerary X-chromosome and skewed X-chromosome inactivation were negligible. Conclusions: Anthropometry and body composition in KS is specific and dysmorphic and affected by AR CAG repeat length and decreased exposure to testosterone already during fetal life.

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X-linked CNV and skewed X-chromosome inactivation

Nauchno-prakticheskii zhurnal «Medicinskaia genetika» ◽

10.25557/2073-7998.2020.03.19-21 ◽

2020 ◽

pp. 19-21

Author(s):

Е.А. Фонова ◽

Е.Н. Толмачева ◽

А.А. Кашеварова ◽

М.Е. Лопаткина ◽

К.А. Павлова ◽

...

Keyword(s):

Cell Proliferation ◽

Intellectual Disability ◽

X Chromosome ◽

Copy Number ◽

Copy Number Variations ◽

X Chromosome Inactivation ◽

Chromosome Inactivation ◽

Chromosome X ◽

Skewed X Chromosome Inactivation

Смещение инактивации Х-хромосомы может быть следствием и маркером нарушения клеточной пролиферации при вариациях числа копий ДНК на Х-хромосоме. Х-сцепленные CNV выявляются как у женщин с невынашиванием беременности и смещением инактивации Х-хромосомы (с частотой 33,3%), так и у пациентов с умственной отсталостью и смещением инактивацией у их матерей (с частотой 40%). A skewed X-chromosome inactivation can be a consequence and a marker of impaired cell proliferation in the presence of copy number variations (CNV) on the X chromosome. X-linked CNVs are detected in women with miscarriages and a skewed X-chromosome inactivation (with a frequency of 33.3%), as well as in patients with intellectual disability and skewed X-chromosome inactivation in their mothers (with a frequency of 40%).

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Faculty of 1000 evaluation for Cellular resolution maps of x chromosome inactivation: implications for neural development, function, and disease.

F1000 - Post-publication peer review of the biomedical literature ◽

10.3410/f.718235579.793490044 ◽

2014 ◽

Author(s):

Franck Polleux ◽

Julien Courchet

Keyword(s):

X Chromosome ◽

Neural Development ◽

X Chromosome Inactivation ◽

Chromosome Inactivation ◽

Cellular Resolution

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X-Linked Emery–Dreifuss Muscular Dystrophy: Study Of X-Chromosome Inactivation and Its Relation with Clinical Phenotypes in Female Carriers

Genes ◽

10.3390/genes10110919 ◽

2019 ◽

Vol 10 (11) ◽

pp. 919 ◽

Cited By ~ 1

Author(s):

Viggiano ◽

Madej-Pilarczyk ◽

Carboni ◽

Picillo ◽

Ergoli ◽

...

Keyword(s):

Muscular Dystrophy ◽

X Chromosome ◽

Clinical Symptoms ◽

Fibrous Tissue ◽

X Chromosome Inactivation ◽

Chromosome Inactivation ◽

Cardiac Conduction ◽

Asymptomatic Carriers ◽

Cardiac Symptoms ◽

Female Carriers

X-linked Emery–Dreifuss muscular dystrophy (EDMD1) affects approximately 1:100,000 male births. Female carriers are usually asymptomatic but, in some cases, they may present clinical symptoms after age 50 at cardiac level, especially in the form of conduction tissue anomalies. The aim of this study was to evaluate the relation between heart involvement in symptomatic EDMD1 carriers and the X-chromosome inactivation (XCI) pattern. The XCI pattern was determined on the lymphocytes of 30 symptomatic and asymptomatic EDMD1 female carriers—25 familial and 5 sporadic cases—seeking genetic advice using the androgen receptor (AR) methylation-based assay. Carriers were subdivided according to whether they were above or below 50 years of age. A variance analysis was performed to compare the XCI pattern between symptomatic and asymptomatic carriers. The results show that 20% of EDMD1 carriers had cardiac symptoms, and that 50% of these were ≥50 years of age. The XCI pattern was similar in both symptomatic and asymptomatic carriers. Conclusions: Arrhythmias in EDMD1 carriers poorly correlate on lymphocytes to a skewed XCI, probably due to (a) the different embryological origin of cardiac conduction tissue compared to lymphocytes or (b) the preferential loss of atrial cells replaced by fibrous tissue.

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