家族性原发性皮肤淀粉样变遗传学分析

目的 探讨家族性原发性皮肤淀粉样变(FPCA)与染色体1q21.3-24.2和5p13.1-q11.2的连锁关系.方法 在染色体1q21.3-24.2和5p13.1-q11.2处选取16个微卫星标记位点,用Linkage软件计算各位点连锁概率.结果 所有位点连锁分析所得的LOD值均<-2,排除了连锁关系.结论 该家系的易感基因不在染色体1q21.3-24.2和5p13.1-q11.2区域,FPCA存在遗传异质性.     

银屑病家系易感基因定位的研究

目的:探讨银屑病易感基因与第4、6、17号染色体上7个微卫星标记的连锁关系,初步对汉族鲁系银屑病易感基因进行定位研究。方法:选择22个银屑病家系中75例患者和正常人51例。选择7个微卫星标记(STR):D6S276、D6S1610、D4S403、D4S424、D4S415、D17S949、D17S784,利用ABI3730测序仪进行电泳测序,并用与之配套的GeneScan、GeneMapper软件进行基因分型。利用GENEHUNTER软件对STR的基因分型数据进行连锁分析。结果:D17S949、D17S784位点的最大两点LOD值,最大两点NPL值均大于1(P<0.05),提示存在连锁关系。结论:染色体17q23~17q25区域内存在寻常型银屑病易感基因。     

全基因组扫描定位遗传性对称性色素异常症易感区域

目的 确定遗传性对称性色素异常症易感区域.方法 用覆盖全基因组22条常染色体的402个微卫星标记对2个遗传性对称性色素异常症大家系进行全基因组扫描,利用Linkage软件(5.10Version)和Cyrillic软件(2.01Version)进行连锁和单倍型分析.结果 常染色体显性遗传模式,外显率为100%时,在1号染色体上的微卫星标记D1S2343处获得最大累积LOD积分为8.85(重组率θ=0.00),其相邻2个标记D1S2696和D1S2345处的最大累积LOD积分分别为4.60(重组率θ=0.10)和8.54(重组率θ=0.00).单倍型分析将易感区域缩小至D1S2696和D1S2635之间11.6cM处.结论 染色体1q11-1q21区域存在遗传性对称性色素异常症易感基因.     

中国汉族人群染色体1q21存在寻常性银屑病易感基因

目的　确定中国汉族人群染色体1q21上是否存在寻常性银屑病易感基因。方法　用覆盖染色体1q21-1q23.1的8个微卫星标记,对36个寻常性银屑病家系共190个个体（包括92例患者,98例正常人;年龄12 ~ 81岁,平均44岁）进行基因组扫描研究,并用ETDT及GENEHUNTER软件进行连锁不平衡分析。结果　GENEHUNTER示D1S2345与银屑病连锁,其非参数连锁（NPL）值为1.735（P = 0.0329）;扩大范围传递不平衡检验（ETDT）示D1S2346的97 bp等位基因与D1S484的283 bp等位基因分别优先传递给患病子代（P < 0.05）。结论 中国汉族人群染色体1q21区存在寻常性银屑病易感基因。     

播散性浅表光线性汗孔角化病致病基因的定位

目的 对播散性浅表光线性汗孔角化病(DSAP)的致病基因进行定位。方法 收集一个DSAP家系成员的血样抽提基因组DNA,选用12号染色体长臂上已知致病区域的7个微卫星标记进行基因扫描,并用LINKAGE软件(5.1Version)对基因分型结果进行连锁分析。结果 连锁分析结果发现本家系在微卫星标记D12S79的两点最大LOD值为5.15(θ=0.00)。结论 DSAP致病基因位于12号染色体的长臂上。     

1q31-32存在新的银屑病易感基因

目的:确定染色体1q是否存在中国汉族寻常型银屑病易感基因位点.方法: 用覆盖染色体1q的12个微卫星标记,对36个寻常型银屑病家系共190个个体(包括92例患者与98例正常亲属)进行基因组扫描研究,并用LINKAGE、ETDT及GENEHUNTER软件进行统计处理.结果:①LINKAGE分析示D1S2891的LOD值为1.0750(θ=0.2),支持连锁;②GENEHUNTER示D1S249、D1S2772和D1S2891的NPL值均大于1.6,相应P<0.05;③ETDT示D1S249 170 bp等位基因和D1S413 258 bp等位基因分别优先传递给正常子代.结论: 中国汉族人1q31-32区存在银屑病易感基因.     

多发性家族性毛发上皮瘤致病基因的确定

目的 对多发性家族性毛发上皮瘤一家系进行基因定位及候选基因突变检测。方法 共用18对覆盖9p21和16q12-q13的微卫星标记对一个多发性家族性毛发上皮瘤家系进行局部基因组扫描,并用Linkage软件进行两点参数连锁分析,最后PCR扩增CYLD1基因的17个编码外显子及其邻近剪接子并进行双向直接测序。结果 ①两点参数连锁分析在常染色体显性遗传模式下,外显率为99.9%、基因频率0.00001时在D16S3068位点处得出LOD值=3.31(θ=0.00),排除与9号染色体连锁;②突变分析在CYLD1基因第18号外显子出现连续的4个碱基缺失,即c.2355-2358delCAGA。结论 多发性家族性毛发上皮瘤存在着遗传异质性,本家系的致病基因位于16q12-q13,而不在9p21。     

毛囊闭锁三联征一家系调查及基因研究

目的:确定一毛囊闭锁三联征(AI)家系的临床特点及易感位点连锁情况.方法:调查该家系临床资料,用1p21.1-1q25.3,6q25.1-25.2,D19S911-D19S1170和19q13.1-19q13.2易感基因位点附近的19个微卫星标记对该家系进行基因分型、连锁分析和单倍型分析.结果:该家系4代39人中13例患毛囊闭锁三联征,男8例,女5例,每代均有个体发病,符合常染色体显性遗传模式.经分析未发现上述位点与该家系存在连锁关系.结论:推断有新的易感位点与AI的发生有关,提示AI具有遗传异质性.     

原发性皮肤淀粉样变一家系致病基因的连锁分析

目的: 探讨家族性原发性皮肤淀粉样变(FPCA)致病基因与染色体1q23,5p13.1-q11.2以及10号染色体近着丝粒区的连锁关系.方法: 采用10个荧光微卫星标记对一FPCA家系进行连锁分析,在染色体1q23,5p13.1-q11.2以及10号染色体近着丝粒区选择10个荧光微卫星标记.通过Linkage5.1软件包计算连锁概率.结果: 各位点连锁分析所得的LOD值均小于-2,显示该家系致病基因与这10个位点均不连锁.结论: FPCA存在遗传异质性,该家系的致病基因可能在其他新的基因位点上.     

6号染色体短臂存在银屑病易感基因的证据

目的 鉴定6号染色体短臂上是否存在寻常性银屑病的易感基因.方法用6号染色体短臂上的8个微卫星标记对46个寻常性银屑病家系共272个个体(包括143例患者和129例非患者)进行基因分型研究,并用Genehunter软件(2.0 Version)对基因分型结果进行两点和多点参数和非参数连锁分析.结果①两点连锁分析:非参数连锁分析揭示3个相邻的标记D6S276、D6S1610和D6S1575的NPL值分别为2.69、3.58和2.84,对应的P值分别为0.0 048、0.0 006和0.0 033;参数分析在D6S1610位点处得出HLOD=4.01和较高的连锁家系比例α=70%.②多点连锁分析:在44.9-62.3 cM的染色体区域内,非参数连锁分析的NPL值均＞3,D6S276(44.9 cM)、D6S1610(53.9 cM)和D6S1575(62.3 cM)均位于这个范围内,其中在D6S1610处NPL值达到最高为4.11,对应的P值为0.0 002;参数分析在D6S1610处,得出多点分析的HLOD峰值为3.17,连锁家系比例为60%.结论6号染色体短臂上存在寻常性银屑病的易感基因。     

Evidence for a novel psoriasis susceptibility locus at 9q33-9q34 in Chinese Hans

Psoriasis is a heterogeneous disease for which nine linkage loci (PSORS loci 1-5 and PSORS7-10) have been accepted by the Human Genome Nomenclature Committee and an additional 16 potential susceptibility loci have been reported so far. Our previous genome-wide scan in 61 Chinese Han psoriasis vulgaris families found two susceptibility loci at 6p21.3 and 4q31 and additional suggestive linkage evidence at other regions, including 9q33. In this follow-up study, the linkage evidence at 9q33 was further investigated using an expanded sample of 160 families and improved marker coverage. Our follow-up linkage analysis of the 160 families demonstrated strong linkage evidence (P < or = 0.000022) throughout a region between 133.38 and 146.23 cM with a maximum nonparametric linkage (NPL) score of 4.64 (P = 0.00000023) and a heterogeneity LOD (HLOD) score of 5.03 (alpha = 46%) at 142.39 cM near the marker D9S290. By stratifying the 160 families into the subtypes of 130 early-onset and 30 late-onset families, we revealed stronger linkage evidence in the early-onset psoriasis families with a maximum multipoint HLOD score of 6.48 (alpha = 58%) and a maximum NPL score of 4.69 (P = 0.00000012) near marker D9S290. Our follow-up study has confirmed a novel susceptibility locus at 9q33-34 for early-onset psoriasis in the Chinese population.     

Evidence for a major psoriasis susceptibility locus at 6p21(PSORS1) and a novel candidate region at 4q31 by genome-wide scan in Chinese hans

Psoriasis is a heterogeneous disease with seven major psoriasis susceptibility loci reported so far on chromosomes 1p, 1q, 3q, 4q, 6p, 17q, and 19p, respectively. To investigate the psoriasis susceptibility loci in Chinese Hans, a genome-wide scan was performed with two-point and multipoint parametric and nonparametric linkage analyses in 61 multiplex families. These families were Chinese Hans residing in east and south-east China, comprising 189 affected and 166 unaffected individuals. We detected evidence for linkage at 6p21 (PSORS1) with nonparametric linkage scores > 3 in the range of 39.9-62.3 cM and a maximum multipoint nonparametric linkage score of 4.58 (p=0.000032). Parametric analysis revealed a maximum two-point heterogeneity lod score of 4.30 with 58% as the proportion of linked families (alpha) and a maximum multipoint heterogeneity lod score of 4.25 (alpha=53%) under the assumption of a dominant model. We could not confirm a previous reported locus (PSORS3) on distal chromosome 4q; however, a region of highly suggestive linkage was identified proximal to this proposed locus. Multipoint nonparametric analysis demonstrated nonparametric linkage scores > 3 throughout a region between 152.5 cM and 165.1 cM (from pter) with a maximum peak of 3.69 (p=0.00033) at 157.9 cM, which locates D4S413. A maximum multipoint heterogeneity lod score of 2.31 (alpha=46%) was reached at 163.1 cM. With two-point parametric linkage analysis, we observed the highest lod score of 2.43 and heterogeneity lod score of 3.94 (alpha=77%) at marker D4S1597. Our results showed that chromosomes 6p and 4q may contain genes involved in the susceptibility to psoriasis vulgaris in a Chinese Han population. Other regions with weaker evidence for linkage could also hide minor susceptibility genes.     

Fine mapping of the PSORS4 psoriasis susceptibility region on chromosome 1q21

Psoriasis is a chronic skin disorder affecting approximately 2% of the Caucasian population. Family clustering of the disease is well established and nonparametric linkage analyzes have mapped disease susceptibility loci on chromosomes 6p (PSORS1) and 17q (PSORS2). Nonconfirmed evidence for linkage is also available for chromosomes 2q 3q, 4q (PSORS3), 8q, 16q, and 20p. We mapped an additional susceptibility locus on chromosome 1q21 (PSORS4). In this study, we have carried out a linkage disequilibrium analysis, in order to achieve a finer localization. We recruited 79 triads from continental Italy and typed them at five loci spanning the 1.6 Mb region generating the highest multipoint LOD scores in our previous linkage study. We observed significant evidence for association with D1S2346 marker (p = 0.004). Results consistent with this data were obtained by typing an independent sample that included 28 patients and 56 controls, originating from Sardinia. In fact, p values of 0.02 were observed with both D1S2346 and D1S2715 markers. We sought further confirmation of our results by typing both samples with two novel markers (140J1C and 140J1D) flanking D1S2346. Marker 140J1D generated a p value of 0.003 in the continental Italy sample where a D1S2346/140J1D haplotype was found with a higher frequency among patients' chromosomes. Altogether our data indicate that the 1q21 susceptibility gene may be localized in the genomic interval spanned by D1S2346 and 140J1D. This report provides evidence supporting the refinement of a non-HLA psoriasis susceptibility locus.     

Genome‐wide linkage scan for psoriasis susceptibility loci in multiplex Tunisian families

Background Psoriasis is a relapsing chronic inflammatory skin disease affecting all population groups, with a peak prevalence of 3% in northern European and Scandinavian caucasians. Epidemiological studies have implicated a genetic component to psoriasis. In the past 12 years multiple genome‐wide linkage analyses have identified putative susceptibility loci on several chromosomes, with a major locus in the major histocompatibility complex region. Objectives To investigate the genetic basis of familial psoriasis in the Tunisian population using a genome‐wide linkage scan in seven multiplex psoriatic families from Tunisia. Methods Following single nucleotide polymorphism (SNP) genotyping on the Affymetrix 10K SNP array, we performed nonparametric linkage (NPL) multipoint analyses to identify genotypes and obtain evidence for linkage with psoriasis across the genome. Results No chromosomal region gave consistent evidence for linkage, providing evidence for genetic heterogeneity in Tunisian psoriasis families. Significant evidence for linkage of psoriasis to chromosome 2p12 was seen in one family. We also identified several regions of tentative psoriasis linkage on chromosomes 2q, 4q, 6p, 11q, 12q, 9q and 13q. One family exhibiting suggestive evidence for linkage to 17q25 (PSORS2) was identified and all affected members harboured a p.Gly117Ser mutation in CARD14 (caspase recruitment domain family, member 14), recently reported to lead to psoriasis in a large family from the U.S.A. Conclusions Our results support the genetic heterogeneity of psoriasis in the Tunisian population, provide confirmatory evidence for a novel psoriasis locus at chromosome 2p12 and reveal a psoriasis family with a mutation at PSORS2.     

Meta-analysis of genome-wide studies of psoriasis susceptibility reveals linkage to chromosomes 6p21 and 4q28-q31 in Caucasian and Chinese Hans population

Ten genome-wide scans have been conducted over the past few years in the search for psoriasis susceptibility genes, but only one potential susceptibility region has been consistently replicated. A meta-analysis using the genome-search meta-analysis method was undertaken combining the results of six of these psoriasis genome-wide studies. The results of this analysis revealed linkage to the major histocompatibility complex on chromosome 6p21 that includes the PSORS1 locus. In addition, linkage was also recorded to a region on chromosome 4q28-q31 previously identified only in a Chinese Hans population. Both these regions were statistically significant even after correction for multiple testing. A possible reason for the erratic replication of findings could be the large effect of the PSORS1 locus (6p21) masking the effect of other loci involved in psoriasis. To overcome this problem, we suggest that future studies condition on the effect of the PSORS1 locus.     

Follow-up analysis of 180 Chinese Han families: identification of a novel locus for psoriasis at 2p22.3-11.2

BACKGROUND: Psoriasis is a common inflammatory and hyperproliferative skin disease. The pathogenesis of psoriasis remains obscure. Family and twin studies have suggested a strong genetic susceptibility to psoriasis. Eight linkage loci (PSORS1-7, PSORS9) were identified and accepted by the OMIM and an additional 16 susceptibility loci have been suggested so far. OBJECTIVES: To investigate further three suggested psoriasis susceptibility loci at 2p22.3-11.2, 13q21-32 and 17q22-25.3 in a Chinese population. Using an expanded sample of 180 Chinese families with psoriasis and improved marker coverage, we verified whether they were Chinese Han psoriasis susceptibility loci. METHODS: In total, 180 Chinese Han families with psoriasis vulgaris (including the 61 families used in the original genome-wide scan and 119 new families) were recruited from the Dermatology Department at the First Hospital Affiliated to Anhui Medical University. Two-point and multipoint parametric and nonparametric linkage (NPL) analyses were performed at 2p, 13q and 17q in the total 180 families as well as the 61 original and 119 new families separately. RESULTS: At the region 2p, a maximum multipoint NPL score of 4.11 was identified at locus D2S337 (P=0.000003), and a maximum multipoint heterogeneity LOD (HLOD) score of 4.93 (alpha=54%) was identified at the same locus in the analysis of the 180 families. However, the analysis of the 180 families did not identify any significant linkage evidence at the region 13q21-32 [a maximum multipoint HLOD score of 0.10 (alpha=7%) and NPL score of 0.95 (P=0.14)] or the region 17q22-25.3 [a maximum multipoint HLOD score of 0.08 (alpha=6%) and NPL value of 0.94 (P=0.14)]. For these two regions, the LOD scores from the 180 families as well as the 119 new families were much smaller than the ones obtained from the original 61 families. CONCLUSIONS: Our study indicates that 2p22.3-11.2 is a novel psoriasis susceptibility locus in the Chinese Han population and confirms that psoriasis is a genetically heterogeneous disease.     

Analysis of chromosome 5q31-32 and psoriasis: confirmation of a susceptibility locus but no association with SNPs within SLC22A4 and SLC22A5

We have previously reported a region on chromosome 5q as a possible susceptibility region for psoriasis. This cytokine cluster-rich region has also been suggested as a susceptibility locus in other autoimmune or inflammatory diseases including Crohn's disease (CD) and rheumatoid arthritis (RA). Three specific single-nucleotide polymorphisms (SNPs) have been reported to associate with RA and CD and to change the functional activity of two organic cation transporters, solute carrier family 22 member 4/5 (SLC22A4) and (SLC22A5). In this study, we have analyzed these SNPs for an association with psoriasis. We have also performed a denser linkage analysis of this region with an additional 31 microsatellite markers. We were not able to detect any association with any of the three SNPs analyzed. However, our linkage result supports the involvement of this region in the etiology of psoriasis. We obtained a peak non-parametric linkage value of 3.1 for marker D5S436 in a subgroup of patients with joint complaints. This result supports the findings in another study of psoriasis patients originating from Iceland in which the authors obtained a peak logarithm of the odds score of 2.6 for marker D5S2090, only 2 Mb from D5S436. This suggests a psoriasis susceptibility locus on chromosome 5q32 that is involved in the arthritic phenotype of the disease.     

Characterization of the major susceptibility region for psoriasis at chromosome 6p21.3.

Psoriasis is a common inflammatory skin condition caused by genetic and environmental factors. Recent genome-wide linkage analyses have identified a locus encoding susceptibility to psoriasis and placed this gene in the 12 cM interval between markers D6S426 and D6S276 on chromosome 6p21.3. This is a broad region and encompasses the human major histocompatibility complex. We have sought to localize the susceptibility gene more precisely by exploiting the linkage, haplotype, and linkage disequilibrium information available through genotyping 118 affected sib pairs, their parents and other affected family members. A total of 14 highly polymorphic markers were genotyped, combining anonymous loci with the class I genes HLA-B and -C distributed across a genetic interval of approximately 14 cM including the entire major histocompatibility complex. Through the application of higher density mapping within the major histocompatibility complex, we identified those regions most commonly shared identical by descent in patients with psoriasis. Using the transmission-disequilibrium test, we found significant evidence of linkage and allelic association across an interval defined by the markers tn62 (p = 1.0 x 10(-7)), HLA-B (p = 4.0 x 10(-7)), and HLA-C (p = 2.7 x 10(-9)), a region encompassed within a 285 kb genomic DNA fragment. Hence these studies contribute to the refinement of the localization of a major psoriasis susceptibility gene and place the critical region near to HLA-C.     

Psoriasis susceptibility locus on 18p revealed by genome scan in Finnish families not associated with PSORS1

The major susceptibility locus for psoriasis, PSORS1, resides on chromosome 6p and includes the candidate genes HLA-C, HCR, and CDSN. Based on a nationwide collection of psoriasis patients and genotyping for the PSORS1 susceptibility haplotype, we selected for a genome scan nine families who do not show association with PSORS1 to more easily detect minor loci for psoriasis susceptibility. In the genome scan, five loci gave initial evidence of linkage and were studied with a denser marker map. After fine mapping, only one locus on 18p11.23 showed suggestive evidence of linkage (nonparametric multipoint linkage analysis score, 3.58; p = 0.0038). The bootstrapping analysis showed that one large family contributed the majority of the linkage (p = 0.0039), but was supported by other families. Haplotype sharing between the linked families and haplotype association analysis gave additional support for the locus. Further, the 18p locus has shown nominal evidence of linkage with psoriasis in the British population. Taken together, these findings confirm the presence of a minor susceptibility locus for psoriasis on 18p11.