Dec 22, 2023; Li et al (Frontiers in Genetics): 20 novel genetic variants associated with the F8 gene and 6 novel genetic variants associated with the F9 gene are identified in the latest study published by Li et al. (2023).
Disclaimer: The content presented herein has been compiled from reputable, peer-reviewed sources and is presented in an easy-to-understand manner for better comprehension. A comprehensive list of sources is provided after the article for reference.
Hemophilia is an X-linked recessive rare genetic disorder. It is categorized into deficient blood clotting which leads to prolonged bleeding and difficulties in clot formation.
The worldwide prevalence of hemophilia is 1 in 50,000 males. 2019 metadata suggests the prevalence in Europe, North America, Australia and New Zealand, Africa, Asia and Latin America is 19.6, 17.8, 16.9, 2.6, 3.8 and 5.0 in 100,000 males, respectively.
Hemophilia A is caused by factor VIII (F8) deficiency while Hemophilia B is caused by factor IX (F9) deficiency. Both genes are situated on the X chromosome at Xq28 and Xq27.1 – 27.2, respectively.
Collectively, symptoms of either hemophilia type are prolonged or trauma-induced bleeding during injury or surgery, Spontaneous bleeding in joints, muscles or internal organs and easy bruising.
As per an online database (CHAMP and CHBMP), over 4,200 pathogenic variants are associated with either type of hemophilia. Among them, 1300 variants have been identified on the F8 while ~1000 variants have been identified on the F9 gene, respectively.
A recent original study published on Dec 22, 2023, in Frontiers in Genetics, named, ‘The variant spectrum of F8 and F9 in hemophilia patients from southern China and 26 novel variants‘ by Li and co-workers identified 26 novel variants associated with hemophilia.
During their research on 193 hemophilia patients 20 novel genetic variants associated with the F8 gene and 6 novel genetic variants associated with the F9 gene are identified. Li et al used Sanger sequencing, multiplex-ligation dependent probe amplification, gap detection, long-range PCR and multiplex PCR techniques in the present study for the detection.
Among the 83 variants detected from the F8 genes, 20 novel variants include 11 insertion and deletions, 5 missense mutations, and 4 nonsense variants. In comparison, 6 novel variants from the F9 gene include 3 missense mutations, 1 non-canonical splice site, and 1 small and 1 large deletion among 24 total variants detected from the F9 gene.
Novel variants identified on the F8 and F9 genes are enlisted here.
| Variant type | F8 | f9 |
| Missense | c.394G>A, c.976C>G, c.1891A>T, c.2099C>G, c.6361A>T, | c.754T>A, c.992T>A, c.1115T>A |
| Nonsense | c.1290T>A, c.2891C>A, c.5063C>A, c.6037G>T, | – |
| Indels | c.795dup, c.1427del, c.1454del, c.1959_1963dup, c.3235dup, c.3348del, c.4342_4343ins, c.5174del, c.5818_5820delinsCACAT, c.6212_6225del, c.4052_4053ins10 | – |
| Non-canonical splice sites | – | c.253-6T>G |
| Small deletion | – | c.252delA |
| Large deletion | – | Exon 6–7 deletion |
Hemophilia is a serious X-linked blood disorder, that poses a significant threat to life. The present study has provided crucial information and found new genetic variations associated with varying degrees of disease severity.
Techniques such as Sanger and next-generation sequencing, and multiplex PCR have emerged as pivotal advancements in the diagnosis as well as early detection of the present condition. These technologies have not only enhanced our understanding of the present conditions but have also helped in prenatal screening, to identify and manage the disorder at its earliest stages.
Read more:
- Positive vs Negative Supercoiling- Explained
- Sanger vs Maxam Gilbert Sequencing- A Technical Comparison
- Sanger Sequencing Analysis 102: Background Noise In Sanger Sequencing
- Sanger Sequencing Analysis 101: A Beginner’s Guide to Sanger Sequencing Peaks
- Technical Checklist for Sanger Sequencing- What No One Tells You!
Source:
- Li, Fucheng, Liya He, Guilan Chen, Yan Lu, Ru Li, Yongling Zhang, Xiangyi Jing, Rujuan Ling, Dongzhi Li, and Can Liao. “Variant Spectrum of F8 and F9 in Hemophilia Patients from Southern China and 26 Novel Variants.” Frontiers in Genetics 14, (2023): 1254265. Accessed December 24, 2023. https://doi.org/10.3389/fgene.2023.1254265.
- CDC Hemophilia Mutation Project (CHAMP & CHBMP) by Central for Disease Control and Prevention.
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