一马凡综合征家系的临床特征及FBN-1基因突变位点

Clinical feature of a family with Marfan syndrome and FBN-1 gene mutation site

目的分析我国一马凡综合征(MFS)家系的临床特征并确定其FBN-1基因突变位点。方法一个4代MFS家系共36人,发病13例。对全部家系成员行眼部及骨骼系统检查,超声心动图测量主动脉根部直径,采集部分患者及亲属共14例的外周静脉血,提取基因组DNA,采用PCR技术扩增FBN-1基因,用ABI Prism310基因分析仪对FBN-1基因所有外显子及内含子进行直接测序。结果发病的13例患者眼部表现为不同程度视力下降伴有双侧晶状体半脱位及高度近视;具MFS面部及骨骼表现,包括关节松弛、细长指趾、漏斗胸或鸡胸、脊柱侧凸等;其中2例患者存在主动脉根部扩张,1例患者存在主动脉瘤同时存在主动脉瓣狭窄及闭合不全。2例患者因心血管疾病猝死。MFS患者FBN-1基因第7外显子存在基因突变,突变核苷酸序列为c DNA中腺嘌呤被鸟嘌呤取代(640A→G),编码的氨基酸由甘氨酸改变为丝氨酸(p.G214S),而在家系健康成员中未发现该种突变。结论该家系发病的13例患者临床特征中眼部症状最常见为近视,具有MFS常见面部及骨骼表现,心血管系统异常少见。该家系MFS患者FBN-1基因突变位点为G214S(640 A→G)。

Objective To identify the clinical feature and FBN-1 gene mutation site of a family with Marfan syndrome （ MFS） in china.Methods Complete physical and ophthalmological examinations and gene analysis were undertaken in a MFS family of 36 members including 13 patients.The Aortic root dimension was measured by ultrasound cardiogram .The genomic DNAs from venous blood of the 14 patients and their relatives were isolated and the entire coding region of FBN-1 was amplified by PCR .The sequence of FBN 1 including all exons and introns was determined with an ABI Prism 310 Genet-ic Analyzer.Results All of these patients in the family manifested various reduced visual acuities with a bilateral lens dis -location and high myopia .All patients had facial and skeletal features of MFS including joint laxity , dolichostenomelia , pectus excavatum or pectus carinatum , and scoliosis.Aortic root dilatation was present in 2 of the 13 patients.One patient had an aortic aneurysm together with either aortic valve stenosis or aortic valve insufficiency .The cause of death for two pa-tients was cardiovascular malformations .We identified a mutation in the 7th exon of FBN1（640 A→G） resulting in the substitution of glycine by serineat codon 214 （p.G214S）.This mutation was not found in unaffected family members of this family.Conclusions The most common clinical features of the patients in this Marfan family were myopia and lens dislo -cation.All patients had facial and skeletal features of MFS .The cardiovascular abnormalities in this family were rare . FBN-1 gene mutation G214S （640A→G） was responsible for the Marfan syndrome patients in a Chinese family .