Franco R, Maffei F, Lourenço D, Piccinato C, Morelli V, Thomazini I, Zago M
Department of Clinical Medicine, Brazil.
Haematologica. 1998 Nov;83(11):1006-8.
A frequent mutation in the cystathionine beta-synthase (CBS) gene (844ins68, a 68-bp insertion in the coding region of exon 8) was recently discovered. In the present study we investigated this mutation as a candidate risk factor for venous thrombosis.
The prevalence of the 844ins68 CBS mutation was determined in 101 patients with objectively diagnosed deep venous thrombosis and in 101 healthy controls matched for age, sex and race. PCR amplification of a DNA fragment containing exon 8 of the CBS gene was employed to determine the genotypes. Additionally, Bsrl restriction enzyme digestion of the PCR products was performed in all samples from carriers of the insertion, to test for concurrent presence of a second mutation (T833C) in the CBS gene.
The insertion was found in 21 out of 101 patients (20.8%; allele frequency 0.109) and in 20 out of 101 controls (19.8%; allele frequency 0.114), yielding a relative risk for venous thrombosis related to the 844ins68 CBS mutation close to 1.0. In addition, the T833C CBS mutation was detected in all alleles carrying the 844ins68 CBS insertion, confirming the co-inheritance of the two mutations.
Our findings do not support the hypothesis that the 844ins68 mutation in the CBS gene is a genetic risk factor for venous thrombosis.
最近发现胱硫醚β-合酶（CBS）基因存在一种常见突变（844ins68，外显子8编码区插入68个碱基对）。在本研究中，我们调查了这种突变作为静脉血栓形成的候选危险因素。
在101例经客观诊断为深静脉血栓形成的患者以及101例年龄、性别和种族匹配的健康对照中，确定844ins68 CBS突变的患病率。采用聚合酶链反应（PCR）扩增包含CBS基因外显子8的DNA片段来确定基因型。此外，对所有插入突变携带者的样本进行Bsrl限制性内切酶消化，以检测CBS基因中是否同时存在第二个突变（T833C）。
在101例患者中有21例（20.8%；等位基因频率0.109）发现该插入突变，在101例对照中有20例（19.8%；等位基因频率0.114）发现该突变，与844ins68 CBS突变相关的静脉血栓形成的相对风险接近1.0。此外，在所有携带844ins68 CBS插入突变的等位基因中均检测到T833C CBS突变，证实了这两种突变的共同遗传。
我们的研究结果不支持CBS基因844ins68突变是静脉血栓形成遗传危险因素的假说。
