These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Factor XII Osaka: abnormal factor XII with partially defective prekallikrein cleavage activity.
    Author: Iijima K, Arakawa Y, Sugahara Y, Matsushita M, Moriguchi Y, Shimohiro H, Nakagawa M.
    Journal: Thromb Haemost; 2011 Mar; 105(3):473-8. PubMed ID: 21264442.
    Abstract:
    A healthy Japanese male had reduced factor XII (FXII) activity (35%) in contrast to normal antigen levels (81%). The F12 of this proband had a 9775G to C mutation in exon 10 and an 11276G to A mutation in exon 13 that resulted in two amino acid substitutions of Ala324Pro (GCG→CCG) in the proline-rich connecting region and Gly531Glu (GGG→GAG) near the active Ser544 in the catalytic domain. His father had the nucleotide 46T/T and a heterozygous 9775G/C mutation. The FXII activity (32%) and antigen level (38%) of the father were about half that of normal individuals with 46T/T, suggesting a heterozygous cross reacting material (CRM)-negative deficiency. His mother had a 46C/T and heterozygous 11276G/A mutation, and 80% FXII activity was incompatible with the corresponding antigen level (125%), suggesting a heterozygous CRM-positive deficiency. The substitution of Ala324Pro probably caused the CRM-negative mutation and the Gly531Glu caused the CRM-positive mutation. We developed three methods based on chromogenic substrates to assay the distinct functions of FXII, namely its autoactivation on a negatively charged surface, activation by kallikrein cleavage and the prekallikrein cleavage activity of FXIIa. The ratios of autoactivated FXIIa/FXII antigen (0.80-1.10) and of kallikrein-induced FXIIa/FXII antigen (0.86-1.00) in plasma from the proband were within normal ranges, whereas those of FXIIa-induced kallikrein/FXII antigen were reduced to 0.41-0.45. In conclusion, the 9775G to C and 11276G to A mutations of F12 led to a CRM-negative and -positive FXII deficiency, and the F12 with 11276A produced a dysfunctional type of FXII with a partial defect (0.41-0.45) in prekallikrein cleavage activity.
    [Abstract] [Full Text] [Related] [New Search]