新Y-STR DYS605在山西汉族人群中的多态性分布

为了应用更多的Y染色体特异性STR基因座以用于法医学和人类遗传学研究,本文用PCR结合PAGE技术检测128例山西汉族无关男性DYS605等位基因分布状况。结果显示：山西地区汉族男性DYS605基因座观察到22,21,20,19,18共5个等位基因,基因频率分别为0.0156;0.1797;0.4531;0.2891;0.0625。等位基因20和19之间的电泳距离在非变性胶上非常接近,要有足够的电泳距离才能区分。测序表明该基因座包括3个串联重复区,其中一个为可变重复区。20例女性DNA未发现扩增产物。Abstract: We study the polymorphism at DYS605 ,a new tetranucleotide Y-STR locus,in a Chinese Han population of Shanxi to meet the need of more genetic markers in forensic practice and genetic analysis. DNA were extracted from 128 unrelated male venous blood, and amplified using GDB primers. PCR products were detected using non-denaturing polyacrylamide gel electrophoresis and silver staining. Five alleles named 22,21,20,19,18 were observed with frequency of 0.0156;0.1797;0.4531;0.2891;0.0625. PCR products were not found in female DNA. Using a long enough gel for a long electrophoresis time is strongly encouraged because the rung between allele 20 and allele19 is smaller than expected. Allele sequences show that the repetitive units of DYS605 were composed with the variant units and non-variant units.     

山西汉族17个Y-STR基因座遗传多态性及遗传关系

为了调查山西汉族群体17个Y-STR基因座的多态性分布,探讨其群体遗传学及法医学应用价值,文章应用Y-filer TM试剂盒检测222名山西汉族无关男性个体的17个Y-STR基因座,用ABI3130遗传分析仪进行基因分型,计算等位基因频率及单倍型多样性,并结合已公开发表的国内其他13个群体相关数据资料,分析山西汉族群体遗传距离和聚类关系。结果:山西汉族个体中共检出219种单倍型,单倍型多样性为0.9999;基因多样性GD值在0.3894(DYS391)~0.9755(DYS385a/b)。从遗传距离分析发现,山西汉族与吉黑汉族之间的遗传距离最近(?0.0001),与台湾群体(0.0152)之间的遗传距离相对较远。结果表明该17个Y-STR基因座在山西汉族群体中具有丰富的遗传多态性,对建立Y染色体STR数据库、研究群体遗传学和进行法医学应用有重要意义。     

福建畲族群体17个Y-STR基因座单倍型及遗传关系

应用Y-filerTM试剂盒及基因分型技术,检测152份福建畲族无关男性个体17个Y-STR基因座的多态性分布,计算等位基因频率及单倍型多样性,并结合已公开发表的其他11个群体相应基因座的单倍型资料,分析福建畲族群体遗传距离和聚类关系。福建畲族DYS385a/b基因座检出50种单倍型,其余15个Y-STR基因座分别检出3-11个等位基因,基因多样性GD值在0.4037(DYS391)～0.9725(DYS385a/b);观察到DYS19和DYS390基因座双等位基因和DYS385a/b基因座三等位基因,以及DYS448等部分基因座出现的"off-ladder"等位基因现象。17个Y-STR基因座共同构成的单倍型144种,其中138种单倍型出现1次,5种出现2次,1种出现4次,累计GD值为0.9990。从遗传距离分析发现,福建畲族与浙江汉族之间的遗传距离最近(0.0042),与青海藏族(0.2378)之间的遗传距离相对较远。福建畲族最靠近由台湾群体、浙江汉族、南方汉族等典型南方汉族群体聚成的分支区域。结果表明该17个Y-STR基因座在福建畲族群体中具有丰富的遗传多态性,对建立Y染色体STR数据库,研究群体遗传学和进行法医学应用有重要意义。     

赣南地区汉族人群29个Y-STR基因座的遗传多样性及系统进化分析

研究赣南地区汉族人群29个Y-STR基因座的遗传多态性以及与国内多个民族群体的遗传关系,探讨其在群体遗传学和法医学中的实际应用价值。采用DNATyperTM Y29试剂盒对1532例赣南地区健康男性无关个体进行Y-STR基因座扩增,3730型遗传分析仪进行毛细管电泳检测,运用GeneMapper IDX1.4软件对数据结果进行Y-STR分型,计算29个Y-STR基因座的等位基因频率及单倍型频率等遗传学参数。应用Mega-X软件对选取的群体构建进化树,用YHRD在线工具软件的分子方差分析(AMOVA),计算群体间遗传距离,同时构建多维尺度图(MDS)。经分析,29个Y-STR基因座在赣南汉族人群中的基因多样性(GD)值范围为0.3815~0.8766,除了DYS508、DYS437、DYS391和DYS438基因座外,其余25个基因座GD值均高于0.5,且单倍型多样性为0.999924,表明29个Y-STR基因座在赣南汉族人群中有较高的遗传多态性。与其他地区汉族人群比较,赣南汉族与福建汉族遗传距离最近(遗传距离Rst值是0.0002),与黑龙江汉族遗传距离最远(Rst值是0.0249);与其他地区少数民族人群比较,赣南汉族与云南白族遗传距离最近(Rst值是0.0059),与甘孜藏族遗传距离最远(Rst值是0.4689)。研究表明,这29个Y-STR基因座在赣南汉族人群中具有较好的遗传多态性分布,能够满足家系排查及法医学检案的要求,所得的数据可为该地区的群体遗传学和法医学研究与应用提供基础数据支持。     

我国东北地区3个群体DYS390多态位点的遗传学研究

目的　研究中国群体Y染色体微卫星位点 DYS390遗传多态性 ,可以用于追溯人类进化上的父系祖先 ,也可以为人类基因组和法医学等研究积累数据。方法　采用 PCR技术扩增微卫星DNA片段 ,再经变性凝胶电泳及银染方法 ,对我国东北地区汉族、蒙古族及朝鲜族 3个群体的1 0 2例男性个体的 DYS390位点的遗传多态性进行了研究。结果　除汉族群体发现 5种等位基因外 ,朝鲜族和蒙古族群体均检出 4种。在汉族群体中 ,我们检出 1例具223bp等位基因。等位基因频率分布在汉族、朝鲜族以211bp的频率为最高 ,分别为0.439和0.451 ;而蒙古族群体则以215bp的频率为最高 (0.433)。结论　 3个群体之间 DYS390位点等位基因频率无显著性差异 ( Fisher精确概率检验 :P=0.930 )。 3个群体中DYS390位点 5种等位基因的分化程度以223bp为最高 ,分化程度最低的为211bp。聚类分析表明3个群体的父系亲缘关系较为密切 ,其中以汉族与朝鲜族之间的遗传距离最近。     

克里雅河下游封闭人群DYS19和DYS390多态性研究

本文以居住于塔克拉玛干沙漠当中克里雅河下游地区封闭人群(51例男性)为研究对象,采用基因扫描对其DYS19和DYS390两个STR基因座进行基因扫描研究其遗传多态性。对于DYS19基因座,克里雅河下游的封闭人群等位基因分布呈现“M”形分布,以DYS19*14和DYS19*16最常见,基因频率分别为0.353和0．510;对于DYS390基因座,其人群等位基因分布也并非呈现“钟形”分布,而是以DYS390*21和DYS390“24两种基因型基因频率最高,并且DYS390*21为此人群等位基因重复次数最少的基因型,基因频率分别为0．235和0．431,这可能是提示克里雅河下游的封闭人群的来源包含两个不同的群体分支。     

广东汉族22个Y-STR基因座遗传多态性及遗传关系分析

调查了广东汉族群体22个 Y-STR基因座的遗传多态性分布情况, 探讨其群体遗传学及法医学应用价值。通过自行建立的两组Y-STR荧光标记复合扩增体系(MultiplexⅠ: DYS505, DYS533, DYS576, DYS588, DYS634, DYS643; MultiplexⅡ: DYS461, DYS481, DYS504, DYS508, DYS607)和应用进口Powerplex Y System (DYS19, DYS389Ⅰ/Ⅱ, DYS390, DYS391, DYS392, DYS393, DYS385, DYS437, DYS438, DYS439), 对广东汉族216 名无关男性个体进行22 个STR基因座的复合分型, 用ABI310基因分析仪对扩增产物进行检测, 统计22 个Y-STR基因座的群体遗传学参数, 并结合已公开发表的其他12 个群体“扩展单倍型”的数据资料, 分析广东汉族群体遗传距离和聚类关系。3 组复合扩增系统均可成功进行分型, 基因多样性GD值在0.3299(DYS634)~ 0.9425(DYS385); 22 个Y-STR基因座共同构成的单倍型214 种, 单倍型多样性为0.9999。广东汉族和潮汕汉族的遗传距离最近(-0.0030), 与东北汉族的遗传距离最远(0.0195)。22 个Y-STR基因座联合检测具有丰富的遗传多态性, 对建立Y染色体STR数据库, 研究群体遗传学和进行法医学应用有重要意义。     

中国南方汉族人群6个Y-STR基因座 遗传多态性及法医学应用

为研究中国南方汉族人群DYS393等6个Y-STR基因座的遗传多态性并用于法医学鉴定,通过采用PCR复合扩增和基因测序仪荧光检测方法,检查204个无关男性个体,调查南方汉族的6个Y-STR基因座的单倍型频率,并对93对真父子和38对非父子的亲子鉴定样本进行检测。结果DYS393基因座检出5个等位基因,DYS19基因座检出6个等位基因,DYS389Ⅱ基因座检出8个等位基因,DYS390基因座检出6个等位基因,DYS391基因座检出4个等位基因,DYS385 基因座检出44个等位基因,共检出176种单倍型。93对真父子中,观察到2例分别有1个基因座突变。检测38对非父子,有1个或2个Y-STR基因座排除的案例各有1例（2.6%）;有3 个和3个以上的Y-STR基因座可以排除父子关系的案例为35例（92.1%）;6个Y-STR基因座不能排除父子关系的为1例。结果表明6个Y-STR基因座具有丰富的遗传多态性,可用于法医学个体识别和亲子鉴定。Abstract: To study the genetic polymorphisms of six Y-chromosome specific STR loci in the southern Chinese Han population and apply it in forensic science, six Y-STR loci were amplified by multiple PCR and the PCR products were detected by using ABI PrismTM 377 Sequencer. The haplotype frequencies at 6 Y-STR loci were determined in a total of 204 unrelated males from southern Han population of China. Ninety-three father/son pairs with demonstrated paternity and thirty-eight non-paternity father/son pairs were detected by using our Y-STR system. As a result, the number of alleles for DYS393、DYS19、DYS389Ⅱ、DYS390、DYS391and DYS385 were 5, 6, 8, 6, 4 and 44 , respectively. A total of 176 haplotypes at 6 Y-STR loci were found. Two father/son pairs with single Y-STR mutation were observed in the 93 father/son pairs with demonstrated paternity. Among the 38 non-paternity father/son pairs, one case with one Y-STR exclusion of paternity, one case with two Y-STR exclusions and 35 cases with 3 or more Y-STR exclusions were observed. Non-exclusion of paternity at 6 Y-STR loci was found only in one case. This result indicated that the six Y-STR loci were highly polymorphic and are suitable for personal identification and paternity testing.     

DYS458、DYS534、DYS426和DYS626基因座多态性研究

目的：研究河南汉族群体DYS458、DYS534、DYS426和DYS626四个Y-STR基因座遗传多态性,评估其法医学应用价值。方法：采用PCR扩增和非变性聚丙烯酰胺凝胶电泳及DNA测序分析河南汉族113名无血缘关系、健康男性个体的4个Y-STR基因座基因及单倍型频率分布。结果：4个基因座共发现了24个等位基因,频率分布在0.0177～0.9027,基因多样性（gene diversity,GD）值最低为0.1801（DYS426）,最高为0.8368（DYS626）。113个个体共检测到94个单倍型,其79种为惟一的,单倍型多样性为0.99589。结论：4个Y-STR基因座在河南汉族群体均具有较高的遗传多态性,可应用于法医学个体识别和亲子鉴定。     

广州汉族人群DYS19、DYS389Ⅰ/Ⅱ、DYS390多态性及其单体型

用PCR结合PAGE技术观察111例广州汉族男性DYS19、DYS389Ⅰ/Ⅱ、DYS390等位基因及单体型分布状况。结果显示：广州地区汉族男性DYS19基因座观察到5种等位基因,DYS389Ⅰ观察到4种等位基因,DYS389Ⅱ观察到5种等位基因,DYS390观察到5种等位基因;χ2检验表明上述各等位基因频率分布与其他地区人群存在明显的差异。此外,还观察到72种由上述基因座共同构成的单体型,单体型多样性达0.953。 Abstract: In order to apply a set of useful and high polymorphic Y?STRs in forensic practice and genetic analysis,we performed a population genetic study from Chinese.The allele distributions of the systems DYS19、DYS389Ⅰ/Ⅱ、and DYS390 were investigated in sample of 111 unrelated males from the area of Guangzhou, China.PCR products were detected using polyacrylamide gel electrophoresis and silver staining.5、4、5、5 alleles were observed in locus DYS19、DYS389Ⅰ、DYS389Ⅱ、DYS390 respectively.Different allele frequency distributions were observed when compared to other population.Haplotype frequency date of 72 different types were obtained.     

Direct PCR sequencing of dystrophin polymorphic CACA alleles after purification to remove shadow bands.

A method is described that allows the sequencing of polymerase chain reaction (PCR) products containing CACA repeats. The method was tested using a DNA polymorphism that exists at the 3' end of the dystrophin gene. This polymorphism consists of a variation in the length of a CACA dinucleotide repeat. Four alleles from a total of 16 individuals were sequenced at this locus after the DNA sequence had been amplified by the PCR. Five examples of each of the common alleles were sequenced. For each allele all five sequences were the same. The only example of a rare allele was also sequenced. The PCR products of DNA sequences containing dinucleotide repeats consist of a number of bands differing by 2 bp below the most intense main band. Previously, direct sequencing of the PCR products lead to ambiguities and smearing at and above the CACA repeat. In this paper, the main PCR band was cut out of a sequencing gel and directly sequenced to give a clear DNA sequence. Our results indicate that for a particular allele, all individuals had exactly the same DNA sequence. This implies that with the appropriate choice of oligonucleotide primers, polymorphisms could be detected without electrophoresis.     

Papillomaviruses and herpesviruses as selected risk factors in the etiopathogenesis of cervix neck cancer. II. Use of PCR for isolating DNA of human papillomavirus and Herpes simplex

The aims of the study were to compare polymerase chain reaction PCR with nucleic acid hybridisation HC in the routine diagnosis of HPV infections. Smears collected for PCR were digested for 24 hours using proteinase K. After DNA extraction 174 samples were tested by PCR with human bglobin primers PG04-GH20. The PCR products were separated in 2% agarose gel electrophoresis stained with ethidium bromide. In 80.6% of the samples 256 base pair DNA fragments were observed in the gel in UV light. These samples were tested by PCR with HPV primers MY09-MY11. In 40% of the samples the presence of HPV DNA was confirmed. Next we carried out PCR using a mixture of two pairs of primers bglobin PG04-GH20 and HPV MY09-MY11. DNA for this study was extracted from 24 samples in which the presence of human DNA was not confirmed in the first PCR test and from 7 untested samples. In 21 cases HPV DNA was found to be present in gel electrophoresis. The presence of HPV DNA was confirmed in 44.75% of the samples.     

Comparison of methods for total community DNA extraction and purification from compost

The differences on DNA yield and purity of three different DNA extraction protocols were compared with regard to the use for PCR and other molecular analyses. Total DNA was extracted from compost by the three protocols, and then was purified by spin-bind cartridges after being precipitated by PEG8000. The detection performed on a nucleic acid and protein analyzer showed that all three methods produced high DNA yields. The agarose gel electrophoresis showed that the fragments of crude and purified DNA had a length of about 23 kb. A eubacterial 16S rRNA gene-targeted primer pair was used for PCR amplification, and full length 16S rDNAs were amplified from all the purified DNA samples. After being digested by restriction endonucleases, the restriction map of amplified rDNA showed identical genetic diversity. The products of PCR using primer pair GC341F and 907R were also used for denaturing gradient gel electrophoresis analysis. The results indicated that high-quality DNA was extracted from compost by the three protocols, and each of the protocols is adapted to extract microbial genome DNA from compost expediently and cheaply.     

Detection of sequence variation in PCR-amplified fragments of omp2 gene from three species of the family Chlamydiaceae using agarose gel electrophoresis containing bisbenzimide-PEG

A simple technique providing a means for rapid genetic differentiation of chlamydial strains is described. The technique is based on a single-step sequence-specific separation of PCR-amplified DNA fragments by electrophoresis in an agarose gel containing a DNA ligand - bisbenzimide-PEG. A hypervariable region at the 5' end of the omp2 gene of Chlamydiaceae species encoding the 60-kDa cysteine-rich outer membrane protein was selected as a target for PCR. The appropriate fragments were amplified from strains of Chlamydia trachomatis, Chlamydophila pneumoniae, and Chlamydophila psittaci, and the PCR products originating from different species were electrophoretically separated in the presence of the DNA ligand. We therefore demonstrated that PCR with a single pair of primers followed by simple agarose gel electrophoresis with bisbenzimide-PEG can be applied to the differentiation of three members of the family Chlamydiaceae which are commonly recognized as human pathogens.     

用普通琼脂糖代替低熔点胶回收DNA片段

为了建立一种直接从普通琼脂糖凝胶中回收DNA片段的简便实用的方法,采用聚合酶链式反应扩增人P53基因外显子7、8和其间的内含子7序列,用普通琼脂糖凝胶电泳,直接从凝胶中切下产物带,用加热熔化法回收DNA;紫外比色法测定回收率;用测序法鉴定回收产物质量。并用QIAquick Spin纯化柱对照。结果表明,本法回收的产物质量明显优于用QIAquick Spin柱回收,本法回收的产物用于测序效果极佳,回收率达80％,用QIAquick Spin柱回收率不到20％,差异非常显著（P<0.01）。证明这种方法回收PCR产物质量可靠,能代替低熔点胶回收DNA,有较大的实用价值。 Abstract： In order to find a simple and efficient method to isolate single or double?strand DNA fragment amplified by polymerase chain reaction (PCR),we used PCR method to amplify exon 7,exon 8 and intron 7 of human P53 gene, electrophoresis to identify products,fusion and phenol-chlorofom extraction (FPC) to isolate specific DNA from agarose gel,ultraviolet colorimetry to deteminate collected rate,and direct sequencing to identify the quality of recollected DNA. A control test was also made by using QIAquick Spin Colum．The results showed that the quality of PCR products recollected by using FPC method was very good．When the recollected DNA was used in sequencing,no matter what was single or double-strand DNA,the sequence data was clear and even,with low noise．The recollected rate of using FPC,which was over 80 per cent, was higher than that of using colum (lessthan 20 per cent), there were statistical significances (P<0.01).In the control test, it had a little non-specific DNA in the collected products,and the sequencing experiment of using double-strand products was failure．All above mentioned suggested that general agarose gelis efficient in place of low melting-temperature for isolating DNA fragment．     

Analysis of any point mutation in DNA. The amplification refractory mutation system (ARMS).

We have improved the "polymerase chain reaction" (PCR) to permit rapid analysis of any known mutation in genomic DNA. We demonstrate a system, ARMS (Amplification Refractory Mutation System), that allows genotyping solely by inspection of reaction mixtures after agarose gel electrophoresis. The system is simple, reliable and non-isotopic. It will clearly distinguish heterozygotes at a locus from homozygotes for either allele. The system requires neither restriction enzyme digestion, allele-specific oligonucleotides as conventionally applied, nor the sequence analysis of PCR products. The basis of the invention is that unexpectedly, oligonucleotides with a mismatched 3'-residue will not function as primers in the PCR under appropriate conditions. We have analysed DNA from patients with alpha 1-antitrypsin (AAT) deficiency, from carriers of the disease and from normal individuals. Our findings are in complete agreement with allele assignments derived by direct sequencing of PCR products.     

Determining SNP allele frequencies in DNA pools

Single nucleotide polymorphisms (SNPs) are among the most common types of polymorphism used for genetic association studies. A method to allow the accurate quantitation of their allele frequencies from DNA pools would both increase throughput and decrease costs for large-scale genotyping. However, to date, most DNA pooling studies have concentrated on the use of microsatellite polymorphisms. In the case of SNPs that are restriction fragment length polymorphisms (RFLPs), studies have tended to use methods for the quantitation of allele frequency from pools that rely on densitometric evaluation of bands on an autoradiograph. Radiation-based methods have well-known drawbacks, and we present two alternative methods for the determination of SNP allele frequencies. For RFLPs, we used agarose gel electrophoresis of digested PCR products with ethidium bromide staining combined with densitometric analysis of gel images on a PC. For all types of SNP, we used allele-specific fluorescent probes in the Taqman assay to determine the relative frequencies of two different alleles. Both methods gave accurate and reproducible results, suggesting they are suitable for use in DNA pooling experiments.     

Association of angiotensin converting enzyme (ACE) gene I/D polymorphism and polycystic ovary syndrome (PCOS)

This study was conducted in Turkish patients with polycystic ovary syndrome to determine the frequency of I/D polymorphism genotypes of angiotensin converting enzyme gene, and to examine the role of this polymorphism in polycystic ovary syndrome development. Genomic DNA obtained from 200 persons (100 patients with polycystic ovary syndrome and 100 healthy controls) was used in the study. DNA was multiplied by polymerase chain reaction using I and D allele-specific primers. Polymerase chain reaction products were assessed with a charge coupled device (CCD) camera by being exposed to 2% agarose gel electrophoresis. There was statistically significant difference between the groups with respect to genotype distribution (p < 0.001). The D allele frequency was indicated as 68% and I allele was as 32% in the patients, whereas it was 51.5-48.5% respectively in the control group. As a result of our study we may assert that angiotensin converting enzyme gene I/D polymorphism DD genotype should be considered as a genetic marker in polycystic ovary syndrome development in this Turkish study population.     

Direct molecular analysis of the fragile X syndrome in a sample of Egyptian and German patients using non-radioactive PCR and Southern blot followed by chemiluminescent detection

Molecular genetic analysis of individuals from 6 Egyptian and 33 German families with fragile X syndrome and 240 further patients with mental retardation was performed applying a completely non-radioactive system. The aim of our study was the development of a non-radioactive detection method and its implementation in molecular diagnosis of the fragile X syndrome. Furthermore, we wanted to assess differences in the mutation sizes between Egyptian and German patients and between Egyptian and German carriers of a premutation. Using non-radioactive polymerase chain reaction (PCR), agarose gel electrophoresis and blotting of the PCR products, followed by hybridisation with a digoxigenin-labelled oligonucleotide probe (CGG)₅ and chemiluminescent detection, we identified the fragile X full mutation (amplification of a CGG repeat in the FMR-1 gene ranging from several hundred to several thousand repeat units) in all patients. We observed no differences in the length of the CGG repeat between the Egyptian and German patients and carriers, respectively. However, in one prenatal diagnosis, we detected only one normal sized allele in a female fetus using the PCR-agarose assay, whereas Southern blot analysis with the digoxigenin labelled probe StB 12.3 revealed presence of a full mutation. Our newly established nonradioactive genomic blotting method is based on the conventional radioactive Southern blot analysis. Labelling of the probe StB 12.3 with digoxigenin via PCR allowed the detection of normal, premutated and fully mutated alleles. For exact sizing of small premutated or large normal alleles, we separated digoxigenin labelled PCR products through denaturing poly-acrylamide gelelectrophoresis (PAGE) and transfered them to a nylon membrane using a gel dryer. The blotted PCR-fragments can easily be detected with alkaline phosphate-labelled anti-digoxigenin antibody. The number of trinucleotide repeat units can be determined by scoring the detected bands against a digoxigenated M13 sequencing ladder. Our newly developed digoxigenin/chemiluminescence approach using PCR and Southern blot analysis provides reliable results for routine detection of full fragile X mutations and premutations.     

Association between I/D polymorphism in the ACE gene and sarcoidosis in Turkish patients

Sarcoidosis is a chronic inflammatory disease with a complex pathogenesis and unknown etiology characterized by noncaseating granulomas that invade the lungs, eyes, liver and other organs. Insertion (I)/deletion (D) polymorphism in the gene encoding the angiotensin-converting enzyme (ACE) has been studied to examine the genetic predisposition to sarcoidosis in different populations, but the results have been inconsistent and inconclusive. This study aimed to determine the frequencies of the genotypes and alleles of I/D polymorphism in the ACE gene in Turkish patients as a distinct ethnic group and to investigate whether such polymorphism is associated with predisposition to sarcoidosis. Genomic DNA samples obtained from 154 individuals (70 patients with sarcoidosis and 84 healthy controls) were used in the study. The DNA was amplified using polymerase chain reactions using allele-specific primers. The amplified products were analyzed by 2 % agarose gel electrophoresis followed by UV transillumination. The allele frequencies and genotype distribution of the groups were analyzed using the Chi square test. There were no significant differences between the controls and sarcoidosis cases with respect to genotype distribution (χ² = 4.202, p = 0.122) and allele frequencies (χ² = 1.358, p = 0.244). Our results suggest that I/D polymorphism in the ACE gene does not cause a genetic predisposition to sarcoidosis in Turkish patients.