一个遗传性出血性毛细血管扩张症家系患者的ACVRL1基因突变分析

目的 确定一个遗传性出血性毛细血管扩张症家系患者ACVRL1基因突变位置及分析临床表型.方法 对该家系先证者ACVRL1基因常见突变位置第3、7、8外显子进行PCR和变性高效液相色谱方法筛查,随后DNA测序证实,确定突变位点后,扩增其家系另5名成员的相应区域筛查,并行DNA序列分析.结果 先证者胃黏膜见出血和毛细血管扩张,彩超显示右肾小动静脉瘘;4例患者ACVRL1基因第3外显子145delG,形成移码突变,导致第53密码子为UAG终止密码子,另2名无临床表现者未见此突变.结论 ACVRL1基因145delG突变是这个家系致病遗传基础.     

一例Apert综合征患者的FGFR2基因突变分析

目的 确定1例Apert综合征患者是否存在成纤维细胞生长因子受体2(fibroblast growth factor receptor 2,FGFR2)基因突变.方法 收集患者及其父母的外周血,提取基因组DNA.采用PCR扩增FGFR2基因第7和第9外显子,对PCR产物进行双向测序检测基因突变.结果 发现患者FGFR2基因第7外显子的934 C→G突变,导致了FGFR2蛋白第252位丝氨酸被色氨酸取代(S252W),与国外报道的致病性突变一致.结论 FGFR2基因第7外显子的P34 C→G突变是该例Apert综合征的致病原因.     

Crouzon综合征患儿及其父母FGFR2基因突变1例分析

目的 报告1例Crouzon综合征患儿及其父母基因突变结果。方法 收集1例Crouzon综合征患儿的临床资料，并对患儿及其父母行外周血全外显子组测序检测。结果患儿及其母亲的FGFR2基因发生了突变：FGFR2:c.842(exon7)A>G(p.Tyr281Cys),DNA链第842位置上腺嘌呤A变异为鸟嘌呤G，而患儿父亲该位点为正常的腺嘌呤（A）。结论 Crouzon综合征是一种常染色体显性遗传病，FGFR2是其致病基因，本文证实p.Tyr281Cys是其突变基因，可引起Crouzon综合征，该患儿的基因突变源于其母亲。     

一个中国人Liddle综合征家系的SCNN1G基因新突变及其临床特征

目的 分析2个Liddle综合征家系上皮细胞钠通道编码基因SCNN1B及SCNN1G的基因突变.方法 收集2个临床诊断为Liddle综合征的家系,抽取先证者及其家系成员外周血基因组DNA,PCR扩增上皮细胞钠通道β亚单位编码基因SCNN1B和γ亚单位编码基因SCNN1G第13外显子,产物直接DNA测序进行基因突变检测.结果 例1 SCNN1B基因第13外显子的扩增片段经双向测序显示第564密码子存在CGA-TGA(R-X)杂合无义突变,其家系成员均未发现这一基因突变;例2 SCNN1G基因第567密码子存在CAG-TAG(Q-X)杂合无义突变,2个家系成员携带此突变基因,这一突变位点尚未在国内外报道过,50名无关正常人中未发现此突变基因.结论 对临床诊断的Liddle综合征患者及其亲属,进行基因突变检测有助于确定诊断及早期筛查出家系中的其他患者.编码人类肾小管上皮细胞钠通道γ亚单位基因SCNN1G第13外显子第567密码子CAG-TAG(Q-X)杂合无义突变可能会导致Liddle综合征.     

先天性大疱性鱼鳞病样红皮病基因突变检测

目的 研究1例先天性大疱性鱼鳞病样红皮病散发患者的基因突变情况,探讨基因型与表现型的相关性.方法 应用聚合酶链反应扩增KRT1和KRT10基因的热点突变区,通过DNA直接测序的方法,对先天性大疱性鱼鳞病样红皮病患者、家系中的正常成员和50名无亲缘关系的正常个体的KRT1和KRT10基因进行突变检测.结果 在患者KRT10基因的第1外显子上发现了1个错义突变(467G→A),导致角蛋白10(KRT10)1A区的精氨酸由组氨酸替代(R156H),而家系正常成员和无亲缘关系的50名正常对照中均未发现该突变.结论 KRT10基因第1外显子突变(467G→A)在该例先天性大疱性鱼鳞病样红皮病患病的分子机制中发挥重要作用.     

一个遗传性玻璃体淀粉样变性家系TTR基因的突变检测

目的 对1个遗传性玻璃体淀粉样变性家系进行致病基因分析.方法 采集该家系4个成员(包括临床确诊患者3例,无症状者1例)的外周静脉血,提取基因组DNA.PCR方法扩增TTR基因的4个外显子,产物直接测序进行基因突变检测,同时选择150名无亲缘关系的正常对照.结果 该家系的4例受检者中均检测到TTR基因第3外显子第103位密码子发生了G＞C(Gly103Arg)杂合突变,而150名正常对照中未发现相同的突变.结论 TTR基因Gly103Arg杂合突变可能与该家系遗传性玻璃体淀粉样变性的发病有关.     

Apert综合征患儿FGFR2基因突变分析

目的研究Apert综合征患儿成纤维细胞生长因子受体2（FGFR2）基因突变以及临床特点。方法采集1例Apert综合征患儿及其父母的外周血,提取基因组DNA,应用PCR扩增FGFR2基因第7和第9外显子,对PCR产物进行双向测序检测基因突变。检索PubMed和中国知网数据库中相关文献进行系统分析。结果在患）LFGFR2基因的第7外显子的937碱基发生杂合突变,由c转变为G,导致FGFR2蛋白第253位密码子由脯氨酸变为精氨酸（P253w）,患儿父母均未检测到该基因突变。文献检索国内外已报道15例Apert综合征患儿,其中6例进行FGFR2基因突变分析,5例为S252W突变,1例为外显子Ⅲb／Ⅲc之间杂合缺失突变。结论该例hpert综合征患儿由FGFR2基因937C-G的杂合突变所致。     

一多发性内分泌腺瘤病2A型家系的临床调查及基因分析

目的 进行一多发性内分泌腺瘤病2A型家系的临床调查及基因分析。方法 对一个包括先证者在内共24位成员的MEN2A家系进行临床调查,并提取16位成员外周血基因组DNA,对RET基因的第10、11外显子进行PCR扩增,PCR产物进行直接测序。结果 1、除先证者外该家系有1例患者,曾诊断MEN2A,但拒绝抽血检查;3例疑似患者,已死亡,无法进行基因分析;筛查出1名成员为基因突变携带者,后该成员于家中突发胸闷、面色苍白死亡; 2、经RET基因突变检查证实,该先证者及1名家系成员存在10q 11.2 外显子11 (密码子634 ) RET基因发生点突变：Cys634Arg。结论 本研究该家系存在外显子11的C634位点突变,应常规对所有MEN2A患者及其家系高危成员尽早进行基因突变分析和筛查。     

甲状腺激素抵抗综合征一家系TRβ基因突变研究

目的研究一个甲状腺激素抵抗综合征家系甲状腺激素受β（thyroid hormone receptor β，TRβ）基因（TRβ）突变情况。方法提取患者及14名家系成员、7名健康对照的外周血基因组DNA，PCR分段扩增刀够基因的第7～10外显子，产物纯化后直接进行DNA测序检测突变。结果测序结果，该家系中5名成员TRβ基因第10外显子的1642位核苷酸发生C→G的转换突变，该突变为错义突变，使该位点所编码的氨基酸由脯氨酸变为丙氨酸（P1453A），同时刀够基因第7外显子的第1020位核苷酸发生C→T的转换突变，该突变为一同义突变，其所编码的氨基酸仍为苯丙氨酸（F245F），两种突变均为杂合子突变。结论在中国人中发现1例TRβ基因突变所致的甲状腺激素抵抗综合征家系。     

一个单纯家族性嗜铬细胞瘤家系的VHL基因突变筛查

目的检测一个单纯家族性嗜铬细胞瘤家系的VHL基因突变情况。方法对一个单纯家族性嗜铬细胞瘤家系进行VHL基因突变检测，抽取该家系5例患者及15名血缘亲属外周血基因组DNA，对VHL基因3个外显子进行PCR，产物进行DNA测序。结果该家系5例患者均检测出VHL基因第2外显子上第587位核苷酸A—C突变，该突变导致第125位编码氨基酸由组氨酸（H）转变为脯氨酸（P）。15名家系成员中筛查出7名成员为该突变基因携带者，B超检查发现1例为双侧肾上腺肿瘤，1例为右肾囊肿。该突变为首次报道。结论该嗜铬细胞瘤家系中检测到可能的致病突变，VHL基因检测可早期发现致病基因携带者，建议对单纯家族性嗜铬细胞瘤患者常规进行VHL基因突变筛查。     

A novel mutation (a886g) in exon 5 of FGFR2 in members of a family with Crouzon phenotype and plagiocephaly.

We identified a novel mutation in members of a family with signs of Crouzon syndrome and plagiocephaly. In affected members of the family an A-->G transition was found at position 886 in exon 5 of the fibroblast growth factor receptor 2 (FGFR2) gene. The base change results in the replacement of a lysine by glutamic acid in Ig-like loop III of FGFR2. The unusual finding of plagiocephaly in these Crouzon patients may either be the result of the type of mutation or because of genetic and environmental factors that affect the phenotype in addition to the mutated FGF receptor.     

Crouzon syndrome: mutations in two spliceoforms of FGFR2 and a common point mutation shared with Jackson--Weiss syndrome

Dominant mutations in the fibroblast growth factor receptor2 (FGFR2) gene have been recently identified as causes of fourphenotypically distinct craniosynostosis syndromes, includingCrouzon, Jackson—Weiss, Pfeiffer, and Apert syndromes.These data suggest that the genetics of the craniosynostosissyndromes is more complex than would be expected from theirsimple autosomal-dominant inheritance pattern. Identical mutationsin the FGFR2 gene have been reported to cause both Pfeifferand Crouzon syndrome phenotypes. We now report the finding ofa mutation in exon Illc of the FGFR2 gene in a kindred affectedwith Crouzon syndrome (C1043 to G; Ala344Gly) that is identicalto the mutation previously associated with Jackson—Weisssyndrome. We also report finding in a Crouzon kindred a mutationin the 3' end of exon Illu (formerly referred to as exon 5,exon 7, or exon U) (A878 to C; Gln289Pro) which encodes theamino terminal portion of the lg-like III domain of the FGFR2protein. This exon is common to both the FGFR2 and the KGFRspliceoforms of the FGFR2 gene, unlike all previously reportedCrouzon mutations, which have been found only in the FGFR2 spliceoform.These findings reveal further unexpected complexity in the moleculargenetics of these craniosynostosis syndromes. The data impliesthat second-site mutations in FGFR2 itself (outside of exonIllc) or in other genes may determine specific aspects of thephenotypes of craniosynostosis syndromes.     

Pregnancy following preimplantation genetic diagnosis for Crouzon syndrome

Crouzon syndrome is a dominantly inherited craniosynostosis syndrome which is caused by mutations in the fibroblast growth factor receptor 2 gene (FGFR2). However, a specific point mutation in the FGFR3 gene has also been shown to result in Crouzon syndrome associated with acanthosis nigricans. We report here the first method for preimplantation genetic diagnosis (PGD) of Crouzon syndrome based on multiplex PCR amplification followed by the direct detection of the causative mutation by single-stranded conformational polymorphism (SSCP) analysis. A highly polymorphic short tandem repeat (STR) locus was simultaneously analysed as a control against some forms of contamination. The mutation, carried by the female partner, was a de-novo substitution at codon 338 of the FGFR2 gene. The couple were found to be informative at the D21S11 STR locus. Two clinical PGD cycles were performed, resulting in the biopsy of 36 blastomeres, 25 of which showed amplification at the FGFR2 locus. All of the cells showed expected genotypes at the D21S11 locus with only one incidence of allele drop-out. A total of five embryos were transferred, two in the first cycle and three in the second, resulting in a singleton pregnancy.     

Mutations in the third immunoglobulin domain of the fibroblast growth factor receptor-2 gene in Crouzon syndrome

Craniosynostosis, which affects approximately 1 in 2000 children,is the result of the abnormal development and/or premature fusionof the cranial sutures. Studies of mutations in patients withcraniosynostosis have shown that the family of fibroblast growthfactor receptor genes are extremely important in the correctformation of the skull, and digits. Mutations in the third immunoglobulindomain of fibroblast growth factor receptor 2 (FGFR2), in partof the molecule corresponding to a tissue specific isoform (IIIc),can cause both Crouzon and Pfeiffer syndromes. Two specificmutations in the linking region between the second and thirdimmunoglobulin domains of FGFR2 occur in Apert syndrome. Wepresent here mutations associated with the Crouzon syndrome,also in the third immunoglobulin domain but in an upstream exon.This exon is expressed in both tissue isoforms. Five differentmutations were detected in 11 unrelated individuals. A cysteineto phenylalanine change was found in six individuals. This cysteineforms half of the disulphide bridge maintaining the secondarystructure of the immunoglobulin domain. The first deletion withinan FGFR gene is reported. Together with mutations in exon IIIcthese account for 25 mutations out of 40 Crouzon patients studiedin our combined series (5).     

Novel FGFR2 mutations in Crouzon and Jackson-Weiss syndromes show allelic heterogeneity and phenotypic variability

Mutations have been reported for several craniosynostotic disordersin exon Illa (exon U or 7) or Illc (exon B or 9) of the fibroblastgrowth factor receptor 2 gene (FGFR2). Among the conditionswith FGFR2 mutations are two autosomal dominant syndromes, Crouzonand Jackson–Weiss. In this study, 24 Crouzon and one Jackson–Weisssyndrome patients were screened for mutations in the two exonsby direct sequencing, and mutations were detected in 28% (7/25)of all cases. Five different mutations were found includingtwo novel (W290G, C342W) and two previously reported, recurrentmutations for Crouzon syndrome (A344A, S354C), and one new mutationfor Jackson-Weiss syndrome (C342R). The W290G mutation was foundin exon Illa which is common to both alternatively spliced formsof FGFR2, BEK (expressed predominantly in primordial bones)and KGFR (expressed preferentially in epithelia). Atypical Crouzonsyndrome features of epithelial-derived anal and/or externalear anomalies were present in the two affected family memberswith the mutation. This phenotype possibly reflects the expressionof both mutant BEK and KGFR. In addition, the Jackson-Weisssyndrome mutation, C342R, in exon Illc was observed previouslyin other craniosynostotic syndromes, Crouzon and Pfeiffer. Theseresults underscore the allelic heterogeneity of these conditionsand the complexity of the phenotypic consequences of FGFR2 mutations.     

Mutations in FGFR1 and FGFR2 cause familial and sporadic Pfeiffer syndrome

Pfeifter syndrome (PS) is an autosomal dominant skeletal disorderwhich affects the bones of the skull, hands and feet. Previously,we have mapped PS in a subset of families to chromosome 8cenby linkage analysis and demonstrated a common mutation in thefibroblast growth factor receptor-1 (FGFR1) gene in the linkedfamilies. Here we report a second locus for PS on chromosome10q25, and present evidence that mutations in the fibroblastgrowth factor receptor-2 (FGFR2) gene on 10q25 cause PS in anadditional subset of familial and sporadic cases. Three differentpoint mutations in FGFR2, which alter the same acceptor splicesite of exon B, were observed in both sporadic and familialPS. In addition, a T to C transition in exon B predicting acysteine to arginine substitution was identified in three sporadicPS individuals. Interestingly, this T to C change is identicalto a mutation in FGFR2 previously reported in Crouzon syndrome,a phenotypically similar disorder but one lacking the hand andfoot anomalies seen in PS. Our results highlight the geneticheterogeneity in PS and suggest that the molecular data willbe an important complement to the clinical phenotype in definingcraniosynostosis syndromes.     

A further mutation of the FGFR2 tyrosine kinase domain in mild Crouzon syndrome

We report a family heterozygous for a newly identified mutation in the tyrosine kinase I domain of the FGFR2 gene (1576A > G, encoding the missense substitution Lys526Glu), associated with variable expressivity of Crouzon syndrome, including clinical nonpenetrance. Our observations expand both the clinical and molecular spectrum of this unusual subset of FGFR2 mutations.     

Endocardial cushion defect in a patient with Crouzon syndrome carrying a mutation in the fibroblast growth factor receptor (FGFR)-2 gene

Crouzon syndrome is an autosomal dominant disorder caused by mutation in the fibroblast growth factor receptor (FGFR)-2 gene. Recent findings from animal studies imply a critical role for FGFs in the regulation of cardiac development including cardiac cushion proliferation and valvulogenesis. We report on a 36-year-old woman, who required surgical closure for an atrial septal defect, a clinical feature that has not been previously reported in other patients with Crouzon syndrome. The findings suggest that cardiac investigations are warranted in patients with a diagnosis of Crouzon syndrome.     

Crouzon with acanthosis nigricans. Further delineation of the syndrome

Patients with Crouzon and acanthosis nigricans syndrome show craniofacial features similar to those observed in patients with classic Crouzon syndrome, in addition to acanthosis nigricans with peculiar characteristics. More severe physical manifestations, such as Chiari malformation, hydrocephalus, and atresia or stenosis of the choanas, which are unusual in individuals with classic Crouzon syndrome, are reported in these patients. The molecular abnormality associated with Crouzon syndrome with acanthosis nigricans (CAN) is a transition in the transmembrane domain of the FGFR3 gene that results in an Ala391Glu mutation. We describe two unrelated patients showing this mutation and compare their clinical features with those of other patients with CAN reported in the literature. In addition to craniosynostosis with crouzonoid facies and acanthosis nigricans (present in all patients), melanocytic nevi, choanal atresia or stenosis, hydrocephalus, Chiari malformations and oral abnormalities were observed in the majority of the 35 patients analyzed. Vertebral anomalies and conductive hearing loss were present with less frequency. Some characteristics considered typical of this condition (jaw cementomas, acanthomas and finger abnormalities) were absent in most of the patients.