Novel deleterious mutation in the F12 gene in a Korean family with severe coagulation factor XII deficiency.
Coagulation factor XII (FXII) is involved in the initiation of blood coagulation, fibrinolysis, complement systems, and bradykinin generation. Hereditary deficiency of FXII is caused by mutations in the F12 gene. In this report, we describe a Korean family with severe FXII deficiency from F12 mutations. The proband was a 46-year-old woman and was shown to have a markedly prolonged activated partial thromboplastin time at 126.7 s (reference range, 29-42 s) on routine health checkup. She had no history of bleeding tendency. Complete correction of prolonged activated partial thromboplastin time on mixing test prompted us to perform factor assays, which revealed a markedly decreased FXII activity (<0.5%; below the detection limit). Direct sequencing analyses for F12 showed that the proband was compound heterozygous for two deleterious mutations, c.249delG (p.Q83HfsX12) and c.405C>A (p.C135X). Family study showed that her sister with prolonged activated partial thromboplastin time at 83.8 s and FXII activity less than 0.5% was also compound heterozygous for the mutations. Q83HfsX12 was a novel frameshift mutation in exon 4 of F12, and C135X is a nonsense mutation previously reported in a Korean patient who was homozygous for the mutation. Thus, the C135X mutation is a recurrent mutation in Korean individuals with FXII deficiency, potentially with a founder effect.
Kim
Hee-Jung
HJ
Department of Laboratory Medicine & Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Kim
Hee-Jin
HJ
Kwon
Eui-Hoon
EH
Lee
Ki-O
KO
Park
In-Ae
IA
Kim
Sun-Hee
SH
D018389:Codon, Nonsense; D004252:DNA Mutational Analysis; D005174:Factor XII / Q000235:genetics*; D005175:Factor XII Deficiency / Q000235:genetics*; D005190:Family; D005260:Female; D018703:Founder Effect; D016368:Frameshift Mutation; D006579:Heterozygote; D006801:Humans; D007723:Korea; D008875:Middle Aged; D009154:Mutation; D010314:Partial Thromboplastin Time; D017354:Point Mutation; D017384:Sequence Deletion; D035781:Siblings
D018389:Codon, Nonsense; D005174:Factor XII