A recent study conducted in Saudi Arabia explored novel variants of Factor VIII among patients with haemophilia A to analyse its spectrum, through genetic analysis using the next generation sequencing technique.

Coagulation Factor VIII is a protein encoded by the F8 gene, considered one of the largest genes located on the long arm of the X chromosome. To date, a total of 2320 variants of the F8 gene have been reported in the Human Gene Mutation Database (HGMD, a large database that aims to collect all known gene lesions responsible for diseases). Among persons with severe haemophilia A, the most frequent variant was found in intron 22 inversion, with a frequency rate of 42%. The second most frequent variant is an inversion in intron 1, with a prevalence of approximately 15% among patients with haemophilia A.

The study identified a total of 10 variants in 12 individual DNA samples, including 5 novel and 5 previously reported variants. Clinical data from patients associated with the samples showed that they had less than 1% Factor VIII expression (thus severe haemophilia) with episodic bleeding, and were on one or more treatment regimens. Thus, the newly identified variants are associated with hereditary X-chromosome-linked haemorrhagic disease.

The results obtained from the study will enrich the database of FVIII variants. In addition, they could be useful in the development of genetic screening for potential patients with haemophilia A.



  • F. A. Al-Allaf et al., Identification of six novel factor VIII gene variants using next generation sequencing and molecular dynamics simulation, Acta Biochim Pol.Vol. 66, No 1/2019 23-31,
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Learn more about the meaning of the words you read on this page and learn about the entire glossary on hemophilia.

A protein belonging to the clotting factor category, a group of enzymes involved in the blood-clotting process.

It is encoded by a gene on the long arm of the X chromosome.

Factor VIII is also known as anti-haemophilic factor (AHF).

Product containing a high concentration of freeze-dried factor VIII, used for replacement therapy in the treatment of haemophilia A.

A ereditary genetic illness, characterised by a deficiency of clotting factor VIII, that exposes the individual to a greater risk of both internal and external bleeds.

Haemophilia A is more common in males, whereas females tend to be healthy carriers of the condition.

The typical symptoms of the condition include haemarthroses (joint bleeds) and haematomas (muscle bleeds).

Condition that occurs when factor VIII activity is between 1% and 5%.

Condition that occurs when factor VIII activity is between 1% and 5%.

Condition that occurs when factor VIII activity is <1%.