Pathological mechanism and antisense oligonucleotide-mediated rescue of a non-coding variant suppressing factor 9 RNA biogenesis leading to hemophilia B

Multicenter Study of Diagnostic Tool for Patients with Hemophilia: From Bedside to Comprehensive Investigations

Background

Hemophilia cannot be diagnosed in most laboratories of economically less-developed countries leading to high mortality and morbidity rates.

Aim

A diagnostic tool was established ranging from bleeding assessment and a simple bedside test of mixing venous clotting time (VCT) to comprehensive DNA analysis for patients with hemophilia.

Methods

Patients with known (n=80) and suspected hemophilia (n=14) were included. Their bleeding symptoms were initially evaluated using verified translated-Thai ISTH bleeding assessment tool. Then, blood samples were drawn using a two-syringe technique, 2 mL each was placed in three tubes, for the mixing VCT and citrate blood was kept for coagulogram and coagulation factor assay. Finally, DNA analysis was determined.

Results

A total of 94 patients with hemophilia (A68, B26) defined as severe (A 57, B 17), moderate (A 7, B 5), and mild degrees (A 4, B 4) with the mean (SD) age of 14.0 (11.7) years and 24 normal controls aged 25.5 (4.5), were enrolled in the study. The mean (SD) bleeding score of patients with hemophilia was 13.5 (5.5), which did not significantly differ between patients with hemophilia A and B. The mixing venous clotting time offered the presumptive diagnosis of hemophilia A and B, which were subsequently confirmed by the prolonged APTT, low FVIII:C and FIX:C and mutations on the factor VIII and IX genes.

Conclusion

A diagnostic tool for bleeding assessment, mixing venous clotting time, coagulogram, coagulation factor assay, and DNA analysis for patients with hemophilia has been established in the existing health-care system.

Two sides of the same medal: Noncoding mutations reveal new pathological mechanisms and insights into the regulation of gene expression

Noncoding sequences constitute the major part of the human genome and also of pre-mRNAs. Single nucleotide variants in these regions are often overlooked, but may be responsible for much of the variation of phenotypes observed. Mutations in the noncoding part of pre-mRNAs often reveal new and meaningful insights into the regulation of cellular gene expression. Thus, the mechanistic analysis of the pathological mechanism of such mutations will both foster a deeper understanding of the disease and the underlying cellular pathways. Even synonymous mutations can cause diseases, since the primary mRNA sequence not only encodes amino acids, but also encrypts information on RNA-binding proteins and secondary structure. In fact, the RNA sequence directs assembly of a specific mRNP complex, which in turn dictates the fate of the mRNA or regulates its biogenesis. The accumulation of genomic sequence information is increasing at a rapid pace. However, much of the diversity uncovered may not explain the phenotype of a certain syndrome or disease. For this reason, we also emphasize the value of mechanistic studies on pathological mechanisms being complementary to genome-wide studies and bioinformatic approaches. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing RNA Processing > 3' End Processing RNA in Disease and Development > RNA in Disease.