Factor VIII gene mutations profile in 148 Chinese hemophilia A subjects.
BACKGROUND
Hemophilia A (HA) is a common X-linked recessive bleeding disease caused by mutations in FVIII gene. The identification of mutation in HA subjects can lead to more accurate diagnosis and contribute to the genetic counseling/prenatal diagnosis.


OBJECTIVE
Our objective is to identify the FVIII defects in 148 unrelated Chinese HA subjects and to analyze the potential consequence of novel mutations.


METHODS
FVIII: C was assayed using one-stage method, and FVIII inhibitor was tested using Bethesda method. Intron 22 and 1 inversions were identified by PCR technique. Non-inversion mutations of FVIII gene were identified by direct sequencing. Novel mutations were further analyzed based on a B-domain deleted FVIII crystallographic structure and bioinformatics tools.


RESULTS
The intron 22 and 1 inversions affected 57 and three severe subjects, respectively. Sixty-seven different mutations were identified in non-inversion subjects including 35 novel mutations that were not reported previously. Novel mutations include five nonsense mutations, 15 missense mutations, three insertions, eight small deletions, two splice site mutations and two partial gene deletions. The potential deleterious effects of these novel missense mutations include disruption of the protein core, impairment of inter-domain interaction and FVIII binding with other proteins.


CONCLUSIONS
Similar to other races, intron 22 and one inversions are also recurrent mutation in severe HA subjects monitored in our centre. Sixty-seven mutations (52% novel reported) among 88 non-inversion subjects represent the high degree of heterogeneity of FVIII gene mutations causing HA. Characteristic of HA FVIII gene mutations extend our insight into structure-function relationship of the FVIII molecule.
State Key Laboratory of Experimental Hematology, Department of Thrombosis and Hemostasis, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China.
Feng
F
Xue
Lei
L
Zhang
Tao
T
Sui
Jing
J
Ge
Dongsheng
D
Gu
Weiting
W
Du
Haifeng
H
Zhao
Renchi
R
Yang
D044466:Asian People / Q000235:genetics*; D002681:China / Q000208:ethnology; D015331:Cohort Studies; D018360:Crystallography, X-Ray; D004252:DNA Mutational Analysis; D005169:Factor VIII / Q000737:chemistry / Q000235:genetics*; D006467:Hemophilia A / Q000235:genetics*; D006801:Humans; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011487:Protein Conformation
D005169:Factor VIII