scholarly journals The Effects of the X Chromosome on Intrinsic Functional Connectivity in the Human Brain: Evidence from Turner Syndrome Patients

2015 ◽  
pp. bhv240 ◽  
Author(s):  
Sheng Xie ◽  
Jiaotian Yang ◽  
Zhixin Zhang ◽  
Chenxi Zhao ◽  
Yanchao Bi ◽  
...  
2018 ◽  
Vol 38 (17) ◽  
pp. 4230-4242 ◽  
Author(s):  
Aaron Kucyi ◽  
Jessica Schrouff ◽  
Stephan Bickel ◽  
Brett L. Foster ◽  
James M. Shine ◽  
...  

2019 ◽  
Vol 29 (11) ◽  
pp. 4580-4594 ◽  
Author(s):  
Chenxi Zhao ◽  
Liyuan Yang ◽  
Sheng Xie ◽  
Zhixin Zhang ◽  
Hui Pan ◽  
...  

AbstractTurner syndrome (TS) is caused by the congenital absence of all or part of one of the X chromosomes in females, offering a valuable human “knockout model” to study the functioning patterns of the X chromosome in the human brain. Little is known about whether and how the loss of the X chromosome influences the brain structural wiring patterns in human. We acquired a multimodal MRI dataset and cognitive assessments from 22 girls with TS and 21 age-matched control girls to address these questions. Hemispheric white matter (WM) networks and modules were derived using refined diffusion MRI tractography. Statistical comparisons revealed a reduced topological efficiency of both hemispheric networks and bilateral parietal modules in TS girls. Specifically, the efficiency of right parietal module significantly mediated the effect of the X chromosome on working memory performance, indicating that X chromosome loss impairs working memory performance by disrupting this module. Additionally, TS girls showed structural and functional connectivity decoupling across specific within- and between-modular connections, predominantly in the right hemisphere. These findings provide novel insights into the functional pathways in the brain that are regulated by the X chromosome and highlight a module-specific genetic contribution to WM connectivity in the human brain.


2020 ◽  
Vol 46 (1) ◽  
Author(s):  
Agnieszka Berendt ◽  
Monika Wójtowicz-Marzec ◽  
Barbara Wysokińska ◽  
Anna Kwaśniewska

Abstract Background Bleedings are more frequent in the population of preterm children than among those born at term, much less in older children. The reasons for such bleedings in preterms include plasma factor deficiencies, immaturity of small vessels in the germinal matrix region, prenatal hypoxia or sepsis. They affect the brain tissue, the gastrointestinal tract and the respiratory system, or are manifested by prolonged bleedings from injection sites. Haemophilia is a rare cause of haemorrhages in the neonatal period, and in the female population it is even seen as an extremely rare disorder. Its aetiology in girls is diverse: inheriting defective genes from their parents, skewed X inactivation or a single X chromosome. Case presentation The article presents a case of a preterm girl born in the 28th week of pregnancy, who was diagnosed with severe haemophilia A stemming from the absence of the X chromosome. The girl’s father is healthy, but her mother’s brother suffers from haemophilia. On the second day of the child’s life, a prolonged bleeding from the injection site was observed. A coagulation profile revealed prolonged APTT which pointed to haemophilia A diagnosis. Moreover, a marked clinical dysmorphy, female sex and a negative family history on the father’s side led the treating team to extend the diagnostic procedures to encompass karyotype evaluation. The girl was diagnosed with Turner syndrome. No bleeding to the central nervous system was observed during her hospital stay. Conclusions Preterm children belong to the risk group of bleeding into the central nervous system or haemorrhages in the course of sepsis. Rare causes of such bleedings should also be borne in mind, including haemophilia. The initial symptoms of haemophilia in preterm children occur in the first days of their lives, which is connected with a number of invasive procedures required in that period. Genetic conditions may coexist with one another. Arriving at one diagnosis does not mean one should abandon further diagnostic procedures in cases where additional atypical symptoms are present which do not match the clinical image of a primary disease.


2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Seyedetahere Mousavi ◽  
Batool Amiri ◽  
Saidee Beigi ◽  
Mohammadreza Farzaneh

Abstract Introduction Turner syndrome is a genetic disorder in females and is the result of complete or partial loss of an X chromosome during fertilization. The missing X chromosome is originally either from the mother's ovum or the father's sperm cell. Approximately 45% of patients have the 45,X karyotype and the rest have other variants of Turner syndrome, which are either mosaicism patterns or structural abnormalities of the X chromosome. Here, we report a case of Turner syndrome that is the fifth case of Turner syndrome with balanced Robertsonian translocation of (13;14)(q10;q10), and the sixth case with 44,X chromosomes, reported in the literature thus far. Case presentation A 10.3-year-old Persian girl was brought to our clinic by her parents, with the complaint of failure to thrive and short height. She had been examined and investigated by endocrinologists since the age of 4 years, but no definite diagnosis was made. At the time of presentation, she had been through three provocative growth hormone tests and had been on no medications for about a year. Her physical examination revealed mild retrognathia and micrognathia. Initially, she was started on somatropin treatment which, after 12 months, did not appropriately improve her height velocity. Therefore, a more thorough physical examination was performed, in which high arched palate and low posterior hairline were observed. There was also a difference between target height and patient height standard deviation scores. Karyotype study was requested, and Turner syndrome was confirmed. Conclusion The diagnosis of this case was not straightforward, both because the somatic presentations were not obvious, and because the physicians had not looked for them when performing the physical examinations. This case report introduces a rare 44,X chromosome karyotype of Turner syndrome and highlights the value in using the difference between target height and patient height standard deviation scores as a simple and inexpensive tool for diagnosis of this syndrome.


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