Skewed Inactivation of X Chromosome: A Cause of Hemophilia Manifestation in Carrier Females

The genetic contribution of the X chromosome in age-related hearing loss

Age-related (AR) hearing loss (HL) is the most common sensory impairment with heritability of 55%. The aim of this study was to identify genetic variants on chromosome X associated with ARHL through the analysis of data obtained from the UK Biobank. We performed association analysis between self-reported measures of HL and genotyped and imputed variants on chromosome X from ∼460,000 white Europeans. We identified three loci associated with ARHL with a genome-wide significance level (p < 5 × 10^-8), ZNF185 (rs186256023, p = 4.9 × 10^-10) and MAP7D2 (rs4370706, p = 2.3 × 10^-8) in combined analysis of males and females, and LOC101928437 (rs138497700, p = 8.9 × 10^-9) in the sex-stratified analysis of males. In-silico mRNA expression analysis showed MAP7D2 and ZNF185 are expressed in mice and adult human inner ear tissues, particularly in the inner hair cells. We estimated that only a small amount of variation of ARHL, 0.4%, is explained by variants on the X chromosome. This study suggests that although there are likely a few genes contributing to ARHL on the X chromosome, the role that the X chromosome plays in the etiology of ARHL may be limited.

Clinical, cytogenetic, and genomic analyses of an Ecuadorian subject with Klinefelter syndrome, recessive hemophilia A, and 1;19 chromosomal translocation: a case report

Background

Hemophilia A is considered one of the most common severe hereditary disorders. It is an X-linked recessive disease caused by a deficiency or lack of function of the blood clotting factor VIII. Klinefelter syndrome is a genetic disorder that affects male individuals due to one or more extra X chromosomes, present in all cells or with mosaicism. The aneuploidy is due to either mitotic or meiotic chromosome non-disjunction. Chromosomal translocations are a group of genome abnormalities in which a region or regions of a chromosome break and are transferred to a nonhomologous chromosome or a new location in the same chromosome.

Case presentation

Our subject was born in Ecuador at 36 weeks of gestation by vaginal delivery. At 3 months old, the Factor VIII activity measure showed a 23.7% activity indicating a diagnosis of mild hemophilia A. At 1 year old, the karyotype showed an extra X chromosome, consistent with a diagnosis of Klinefelter syndrome, and a translocation between the long arms of chromosomes 1 and 19, at positions q25 and q13, respectively.

Conclusions

Klinefelter syndrome and hemophilia are a rare combination. In the present case report, the subject presents both, meaning that he has inherited one X chromosome from the father and one X chromosome from the mother. Since the father has severe hemophilia A; and the subject presents a below 40% Factor VIII activity, a skewed X inactivation is suggested. Additionally, the proband presents a translocation with the karyotype 47,XXY,t(1;19)(q25;q13). No similar report with phenotypic consequences of the translocation was found. The present report highlights the importance of a correct diagnosis, based not only on the clinical manifestations of a disease but also on its genetic aspects, identifying the value of integrated diagnostics. The subject presents three different genetic alterations, Klinefelter syndrome, hemophilia A, and a 1;19 chromosomal translocation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13039-022-00618-w.

Acquired Hemophilia A in a Female: A Case Report

INTRODUCTION: Coagulation factor deficit is a very uncommon hemostatic condition in which a single component or numerous factors are lacking. Hereditary coagulation factor defects are autosomal recessive, meaning that they can affect both men and women. However, hemophilia A, caused by lack of clotting factor VIII (FVIII), is an X-linked condition. Acquired hemophilia A (AHA) is a bleeding disorder caused by autoantibodies to FVIII. It should be distinguished from congenital hemophilia, an inherited disorder caused by a mutation in the FVIII gene. Here, we report the first known case in Indonesia, a 24-year-old female diagnosed with AHA. CASE PRESENTATION: A 24-year-old woman was referred to our facility for prolonged epistaxis. She had no previous history of extended menstrual flow or frequent epistaxis episodes, and there was no history of epistaxis or prolonged bleeding in her family. Bleeding time and prothrombin time were both normal, but time to activate partial thromboplastin was longer. The patient was diagnosed with AHA after von Willebrand disease (VWD) was ruled out. DISCUSSION: In some rare situations, females can be affected by X-linked illnesses such as hemophilia A and B. This may be due to a carrier mother or affected father, skewed X chromosome inactivation, Turner syndrome, inhibitory antibodies (acquired hemophilia), or a random mutation on the active X chromosome. In such instances, treatment is challenging. The usual treatment of choice is recombinant coagulation factors. CONCLUSION: Although VWD is the most frequent hereditary bleeding problem in females, other rare disorders such as AHA may be implicated. Clinicians should be aware of this when faced with patients that lack a history of bleeding disorders. Furthermore, AHA should be considered as a differential diagnosis in every female patient suffering from hemorrhage. Therefore, a comprehensive diagnostic approach is needed.

Circular RNA as a Potential Biomarker for Forensic Age Prediction

In forensic science, accurate estimation of the age of a victim or suspect can facilitate the investigators to narrow a search and aid in solving a crime. Aging is a complex process associated with various molecular regulations on DNA or RNA levels. Recent studies have shown that circular RNAs (circRNAs) upregulate globally during aging in multiple organisms such as mice and C.elegans because of their ability to resist degradation by exoribonucleases. In the current study, we attempted to investigate circRNAs’ potential capability of age prediction. Here, we identified more than 40,000 circRNAs in the blood of thirteen Chinese unrelated healthy individuals with ages of 20–62 years according to their circRNA-seq profiles. Three methods were applied to select age-related circRNA candidates including the false discovery rate, lasso regression, and support vector machine. The analysis uncovered a strong bias for circRNA upregulation during aging in human blood. A total of 28 circRNAs were chosen for further validation in 30 healthy unrelated subjects by RT-qPCR, and finally, 5 age-related circRNAs were chosen for final age prediction models using 100 samples of 19–73 years old. Several different algorithms including multivariate linear regression (MLR), regression tree, bagging regression, random forest regression (RFR), and support vector regression (SVR) were compared based on root mean square error (RMSE) and mean average error (MAE) values. Among five modeling methods, regression tree and RFR performed better than the others with MAE values of 8.767 years (S.rho = 0.6983) and 9.126 years (S.rho = 0.660), respectively. Sex effect analysis showed age prediction models significantly yielded smaller prediction MAE values for males than females (MAE = 6.133 years for males, while 10.923 years for females in the regression tree model). In the current study, we first used circRNAs as additional novel age-related biomarkers for developing forensic age estimation models. We propose that the use of circRNAs to obtain additional clues for forensic investigations and serve as aging indicators for age prediction would become a promising field of interest.