马凡综合征一家系的致病基因筛查

目的：对中国辽宁省一个具有常染色体显性遗传特点的马凡综合征( Marfan syndrole, MFS )家系进行突变基因的筛查。
　　方法：分别采集家系成员的外周静脉血,提取基因组DNA,通过对与马凡综合征相关的致病基因进行遗传学研究和分析,选取候选基因并设计引物,应用聚合酶链式反应( PCR)扩增DNA片段后进行琼脂糖凝胶电泳分离,利用直接测序法确定致病基因及其突变位点。
　　结果：该家系遗传方式符合常染色体显性遗传,先证者表型为双眼晶状体向鼻上方脱位,通过对候选基因外显子直接测序,发现该家系内患者原纤维蛋白基因-1(fibrillin-1 gene,FBN1)第7个外显子第640位碱基有1个A>G的点突变,此突变导致蛋白第214位的甘氨酸被丝氨酸取代(G214S)。
　　结论：FBN1基因 c. A640G(p. G214S)突变为该马凡综合征家系的致病因素。

Gene screening in a Chinese family with Marfan syndrome

AlM: To analyze the causative gene mutation for Marfan syndrome ( MFS ) with autosomal dominant hereditary in a Chinese family in Liaoning Province, China.
METHODS:Venous blood was collected and candidate gene was selected to design primers according to the clinical phenotype. With genomic polymerase chain reaction ( PCR ) performed, the coding exons and their flanking intron in sequences of candidate gene were sequenced, DNA fragments separated by agarose gel electrophoresis and direct sequencing method was used to determine the pathogenic gene.
RESULTS:Phenotype of the proband was presented as ectopic lentis. Sequencing of the coding regions of FBN1 gene showed the presence of a heterozygous A→G transversion at nucleotide 640 in the 7 exon of FBN1 and the missense mutation made for Glycine into Serine (G214S).
CONCLUSlON:A heterozygous mutation of FBN1 c. A640G(p. G214S)is responsible for the Marfan syndrome in the four generation Chinese pedigree.