[A heterozygous point mutation G13328A in antithrombin gene causes thrombosis].
OBJECTIVE
To identify the phenotype and the gene mutation in a kindred with antithrombin (AT) deficiency.


METHODS
Immuno-nephelometry and chromogenic assay were used to detect the plasma level of AT antigen (AT: Ag) and activity (AT: A), respectively. All the seven exons and intron-exon boundaries of AT gene from the propositus were amplified by PCR and direct sequencing of the PCR pro-ducts was performed. Corresponding PCR fragments from the kindred were also sequenced directly. Megaprimer method was used to construct the mutant AT cDNA expressing vector from normal plasmid pCRII AT cDNA. The normal and mutant AT plasmid were transiently transfected into Cos-7 cells and AT: Ag was detected in supernatant and lysate of transfected cell with ELISA.


RESULTS
The plasma level of AT: Ag and AT: A for the propositus were 179 mg/L and 42.3%, respectively. A heterozygous G13328A missense mutation in exon 6 was identified, which led to the substitution of Thr (ACC) 404 for Ala (GCC). The sequencing results from the pedigree suggested that three other members also had the mutation. The level of AT:Ag in supernatant and lysate from cells transfected with mutant AT cDNA was 40% and 68% of that of normal AT cDNA transfected cells.


CONCLUSIONS
This is an unreported AT gene mutation in China, which causes type I hereditary antithrombin deficiency and thrombosis in the proposita.
Zhou
Rong-fu
RF
Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Second Medical University, Shanghai 200025, China.
Shi
Guo-chao
GC
Fu
Qi-hua
QH
Wang
Wen-bin
WB
Xie
Shuang
S
Dai
Jing
J
Ding
Qiu-lan
QL
Hu
Yi-qun
YQ
Wang
Xue-feng
XF
Deng
Wei-wu
WW
Wang
Hong-li
HL
D000991:Antithrombins / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D013927:Thrombosis / Q000235:genetics*
D000991:Antithrombins