Park Chang-Hun, Seo Ja-Young, Kim Sun-Hee, Koo Hong Hoe, Kim Hee-Jin
Department of Laboratory Medicine & Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Blood Coagul Fibrinolysis. 2013 Jul;24(5):544-6. doi: 10.1097/MBC.0b013e32835ee0f8.
Haemophilia B is an X-linked recessive bleeding disorder caused by mutations in the F9 gene on Xq27.1, which lead to deficient coagulation factor IX (FIX). The mild form of haemophilia B has been known to be underdiagnosed due to mild clinical symptoms and minimally prolonged activated partial thromboplastin time. We herein describe a sporadic case of mild haemophilia B from a novel missense mutation of F9. The proband was a 4-year-old boy with a mild bleeding history. He had no family history of bleeding tendency. Coagulation screening tests revealed prolonged aPTT at 42.6s (STA-PTT Automate, reference range, 29.1-41.9s) and a decreased FIX activity at 13% in factor assays. Molecular genetic analysis of F9 revealed that he was hemizygous for a missense mutation, c.1048T>G (p.Ser350Ala), which has not been reported previously. His mother was a carrier of the mutation. This case represents a novel missense mutation from non-CpG transversion of F9.
乙型血友病是一种X连锁隐性出血性疾病，由位于Xq27.1的F9基因突变引起，该突变导致凝血因子IX（FIX）缺乏。由于临床症状轻微且活化部分凝血活酶时间延长不明显，已知轻度乙型血友病的诊断率较低。我们在此描述一例因F9基因新的错义突变导致的散发性轻度乙型血友病病例。先证者是一名有轻度出血史的4岁男孩。他没有出血倾向的家族史。凝血筛查试验显示活化部分凝血活酶时间延长至42.6秒（STA - PTT自动分析仪，参考范围为29.1 - 41.9秒），在因子检测中FIX活性降低至13%。F9基因的分子遗传学分析显示，他为错义突变c.1048T>G（p.Ser350Ala）的半合子，此前未见报道。他的母亲是该突变的携带者。该病例代表了F9基因非CpG颠换产生的一种新的错义突变。
