title: [Identification of a novel heterozygous mutation in a pedigree with hereditary coagulation factor XII deficiency].
abstract: OBJECTIVE
  To identify potential mutation underlying hereditary coagulation factor XII (FXII) deficiency in a pedigree and explore its molecular pathogenesis.
  
  
  METHODS
  Activated partial thromboplastin time (APTT), FXII activity (FXII:C) and FXII antigen(FXII:Ag) and other coagulant parameters of the proband and 5 family members were measured. Potential mutations in the 14 exons and intron-exon boundaries of the FXII gene were screened with polymerase chain reaction (PCR) and direct DNA sequencing. Suspected mutations were confirmed with reverse sequencing. Corresponding PCR fragments from other family members were also sequenced.
  
  
  RESULTS
  APPT of the proband and his son were significantly prolonged to 121.5 s and 98.5 s, respectively. FXII:C and FXII:Ag of the proband and his son have reduced to 5%, 6.8% and 9%, 12.2%, respectively. Plasma plasminogen activity (PLG:A) in both individuals was slightly higher than the normal reference range. FXII:C of his second daughter and grandson were slightly reduced to 64% and 60%. FXII:C of the other family members were all in the normal range (72%-113%). A heterozygous missense mutation, g.8597G>A, was identified in exon 13 of the FXII gene in the proband, which resulted in an p.Asp538Asn substitution. For the promoter regions of the FXII gene, the genotype of the proband was 46TT. The same mutations and 46T/T were also found in the proband's son but not in other members of the family. The genotypes of the proband's spouse, eldest daughter and grandson were 46CT, and his second daughter was 46TT.
  
  
  CONCLUSIONS
  The heterozygous mutation of g.8597G>A identified in exon 13 of FXII gene is a novel mutation. Heterozygous p.Asp538Asn mutation and 46TT in the FXII gene can cause hereditary FXII deficiency, which was probably responsible for the low FXII concentrations in this pedigree.
authors.affiliation: Laboratory Medicine Center, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325015, P.R.China. wywms@126.com.
authors.forename: Lihong
authors.initials: L
authors.lastname: Yang
authors.forename: Xiuping
authors.initials: X
authors.lastname: Hao
authors.forename: Yingyu
authors.initials: Y
authors.lastname: Wang
authors.forename: Haixiao
authors.initials: H
authors.lastname: Xie
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Jin
authors.forename: Liqing
authors.initials: L
authors.lastname: Zhu
authors.forename: Mingshan
authors.initials: M
authors.lastname: Wang
mesh_terms: D000328:Adult; D001483:Base Sequence; D005091:Exons; D005174:Factor XII / Q000235:genetics*; D005175:Factor XII Deficiency / Q000151:congenital / Q000235:genetics*; D005260:Female; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010375:Pedigree; D017354:Point Mutation; D055815:Young Adult
chemical_list: D005174:Factor XII