Analysis of the F7gene by PCR amplification and sequencing of the coding region and splice junctions is the gold standard approach.Dosage analysis, via MLPA, is available as a second line test where gross deletions/ insertions are suspected.
Heritable factor VII deficiency is a rare autosomal recessive bleeding disorder, caused by defects in the F7 gene, with a prevalence of 1 in 0.5-1 million. Severe deficiency may be life-threatening, resulting in intracerebral hemorrhage in the first few weeks of life. Otherwise symptoms are similar to those seen in haemophilia including hemarthroses. Most heterozygous patients remain asymptomatic, although some may exhibit a mild bleeding phenotype e.g. menorrhagia, epistaxis, bleeding post dental extraction etc. and may be at increased bleeding risk following trauma or surgery. Thrombotic events have been reported in FVII deficient patients although causality has not yet been established. However, it is clear that FVII deficiency is not protective against thrombosis.
Polymorphisms in the F7 gene, including Arg353Gln and -323 10bp insertion, are asociated with reduced FVII levels and it may be worth screening for these first in asymptomatic cases with borderline FVII levels before undertaking a full F7 screen.
Synonyms or keywords:
Factor VII deficiency.