title: [Phenotypic and genetic analysis of two pedigrees affected with hereditary antithrombin deficiency].
abstract: OBJECTIVE
  To explore the phenotype, genotype and molecular mechanism for two pedigrees affected with hereditary antithrombin (AT) deficiency.
  
  
  METHODS
  Clinical diagnosis was validated by assaying of coagulation parameters including prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen, antithrombin activity (AT:A) and specific antigen (AT:Ag), protein C activity, as well as protein S activity. To detect potential mutations in the probands, all exons, exon-intron boundaries and the 3', 5' untranslated regions were amplified by PCR and subjected to direct sequencing. Suspected mutation was confirmed by reverse sequencing and silver staining. The effect of mutations on the AT protein was analyzed with bioinformatics software.
  
  
  RESULTS
  The AT:Ag of pedigree 1 was normal, but its AT:A has reduced to 30%. A heterozygous c.235C>T mutation in exon 2 causing p.Arg47Cys, in addition with two single nucleotide polymorphisms (c.981G>A, c.1011G>A) in exon 5 were identified in the patient. His four children, except for the elder daughter, were heterozygous for the mutations. The plasma levels of AT:A and AT:Ag in proband 2 have decreased to 39% and 103 mg/L, respectively. A heterozygous deletion (g.5890-5892delCTT) leading to loss of p.Phe121 was also detected in his father. Bioinformatic analysis suggested that the missense mutation Arg47Cys can affect the functions of AT protein. Meanwhile, lacking of Phe121 will result in loss of hydrogen bonds with Ala124, Lys125 and the cation π interactions with Lys125, Arg47, which may jepordize the stability of the protein.
  
  
  CONCLUSIONS
  The proband 1 had type II AT deficiency, while proband 2 had type I AT deficiency. The p.Arg47Cys and g.5890-5892delCTT mutations of the AT gene are significantly correlated with the levels of AT in the two probands, respectively.
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, China. wywms@126.com.
authors.forename: Xiuping
authors.initials: X
authors.lastname: Hao
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Jin
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Cheng
authors.forename: Lihong
authors.initials: L
authors.lastname: Yang
authors.forename: Liqing
authors.initials: L
authors.lastname: Zhu
authors.forename: Mingshan
authors.initials: M
authors.lastname: Wang
mesh_terms: D000328:Adult; D000369:Aged, 80 and over; D000990:Antithrombin III / Q000235:genetics / Q000378:metabolism; D020152:Antithrombin III Deficiency / Q000201:enzymology / Q000235:genetics* / Q000503:physiopathology; D005091:Exons; D005260:Female; D005820:Genetic Testing; D005838:Genotype; D006801:Humans; D008297:Male; D009154:Mutation; D010314:Partial Thromboplastin Time; D010375:Pedigree; D010641:Phenotype; D011486:Protein C / Q000235:genetics / Q000378:metabolism; D017293:Protein S / Q000235:genetics / Q000378:metabolism
chemical_list: D011486:Protein C; D017293:Protein S; D000990:Antithrombin III