ClinVar

This F2 variant is referred to as prothrombin Himi I.

In a girl with dysprothrombinemia (see 613679), Morishita et al. (1992) found a congenitally dysfunctional form of prothrombin, called prothrombin Himi, which was associated with reduced fibrinogen clotting activity, although it retained full hydrolytic activity toward synthetic substrates. Because previous findings suggested that the functional defect of prothrombin Himi was caused by an abnormality in the thrombin portion of the protein, Morishita et al. (1992) amplified the genomic DNA regions corresponding to exons 8 through 14 and applied single-strand conformation polymorphism analysis. Two variant conformers in exon 10 were identified in the proband with this variant: an 8751T-C transition resulting in a met337-to-thr (M337T) substitution inherited from the father, and an 8904G-A transition resulting in an arg388-to-his (R388H; 176930.0007) substitution inherited from the mother.