Leiden Mutation

Leiden mutation is autosomal dominant hereditary mutation in gene for clotting factor V. Consequence of this mutation is blood clotting disturbance factor V is resistant on activated protein C (APC resistance) which is natural inhibitor of clotting cascade.

Mutation is based on change of nucleotide. Guanine is replaced by arginine in position 1691, exon 10 in the gene for factor V. It causes change of amimoacid (arginin is replaced by glutamin) in peptide chain.

Clinical manifestation is trombophilia with its complications:
 * deep vein thrombosis,
 * pulmonary embolism,

and higher risk of:
 * abortions,
 * premature childbirth.

Heterozygotes have 5-10 times higher risk of thrombosis than common population sample, homozygotes even 80-100 times higher risk. There is possible advantage of lower risk of massive bleeding after childbirth. The risk of trombophilia can be enhanced by using hormonal contraception in woman population, which is not recommended to use. Leiden mutation is the most often genetic disturbance of blood clotting, prevalence is 5% in European population. In the opposite side it is quite rare polymorphism in Asia and Africa.

Diagnostic is based on RFLP, PCR and DNA electrophoresis.

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