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1.
中国人群DXS102座位多态性鉴定及其应用 总被引:13,自引:0,他引:13
目的探讨中国人群中DXS102座位的多态分布。方法应用PCR扩增片段长度多态性(Amp-FLP)研究了无亲缘关系的234条X染色体。结果DXS102座位等位片段有8个,核心单元AC二核苷酸重复数为13~21,频率分布在0.013~0.156之间,杂合度观察值和无偏估测值分别为0.87和0.80,多态信息含量(PIC)0.80,女性基因型数为22个,男性基因型数为8个,该座位多态分布符合Hardy-Weinberg平衡定律。DXS102座位在中国人群和欧洲人群的分布有明显的种族差异,在中国人群中发现了两个新的等位片段。应用DXS102座位的短串联重复序列多态性对一接受基因治疗的血友病B家系进行分析和携带者筛查。结论DXS102座位连锁分析有望成为一种有效的血友病B基因诊断的方法。 相似文献
2.
J Kaplan A Pelet H Hentati M Jeanpierre M L Briard H Journel A Munnich J L Dufier 《Journal of medical genetics》1991,28(6):383-388
X linked retinoschisis (RS) is a vitreoretinal disease resulting from microcystic degeneration of the macula associated with peripheral lesions. The disease gene has already been assigned to the distal short arm of the X chromosome (Xp22.2) by linkage studies. In order to contribute both to a better localisation of the RS locus and to genetic counselling in RS families, we have carried out a clinical and genetic analysis in seven pedigrees. We show, first, that in contrast with previous reports, heterozygote carriers frequently express the disease, and display peripheral retinal alterations similar to those found in affected males. Second, while distal markers DXS16, DXS207, and DXS43 are closely linked to the disease locus, a high level of recombination events was found with centromeric markers, namely DXS274, DXS41, and DXS164. These findings must be taken into account for both carrier detection and prenatal diagnosis in X linked RS. 相似文献
3.
X linked myotubular myopathy (MTM1) maps between DXS304 and DXS305, closely linked to the DXS455 VNTR and a new, highly informative microsatellite marker (DXS1684). 总被引:3,自引:2,他引:3
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N Dahl F Samson N S Thomas L J Hu W Gong G Herman J Laporte P Kioschis A Poustka J L Mandel 《Journal of medical genetics》1994,31(12):922-924
The locus for X linked recessive myotubular myopathy (MTM1) has previously been mapped to Xq28 by linkage analysis. We report two new families that show recombination between MTM1 and either DXS304 or DXS52. These families and a third previously described recombinant family were analysed with two highly polymorphic markers in the DXS304-DXS52 interval, the DXS455 VNTR and a newly characterised microsatellite, DXS1684 (82% heterozygosity). These markers did not recombine with MTM1 in the three families. Together with the recent mapping of an interstitial X chromosome deletion in a female patient with moderate signs of myotubular myopathy, our data suggest the following order of loci in Xq28: cen-DXS304-(DXS455, MTM1)-DXS1684-DXS305-DXS52-tel. This considerably refined localisation of the MTM1 locus should facilitate positional cloning of the gene. The availability of highly polymorphic and very closely linked markers will markedly improve carrier and prenatal diagnosis of MTM1. 相似文献
4.
We have identified a compound dinucleotide repeat within intron 7 of the human erythroid 5-aminolevulinate synthase (ALAS2) gene with a minimum of 9 alleles and heterozygosity of 78%. ALAS2 was placed on the multipoint linkage map of the X chromosome in the pericentromeric region with the locus order: pter-(DXS255, TFE3, DXS146)-(DXS14, ALAS2, DXZ1)-AR-(DXS153, DXS159)-qter. No recombination was observed between ALAS2 and the centromere marker DXZ1. As ALAS2 has recently been shown to be the defective locus in X-linked pyridoxine-responsive sideroblastic anemia (PRSA), the ALAS2 marker has allowed placement of the gene for PRSA into the multipoint linkage map of the X chromosome. With the previous exclusion of close linkage between DXS14 and sideroblastic anemia with ataxia, our data show that there are at least two loci for X-linked sideroblastic anemia. 相似文献
5.
Genetic heterogeneity in X-linked agammaglobulinemia complicates carrier detection and prenatal diagnosis 总被引:1,自引:0,他引:1
E. J. B. M. Mensink A. Thompson J. D. L. Schot M. E. M. Kraakman L. A. Sandkuyl R. K. B. Schuurman 《Clinical genetics》1987,31(2):91-96
X-linked agammaglobulinemia (XLA) is a severe antibody deficiency disease reflecting an arrest of B lymphocyte differentiation at the level of precursor B cells. The disease is inherited in an X-linked recessive mode. In a single eight-generation pedigree the XLA gene was mapped to the Xq21.3-Xq22 area of the X chromosome. The data establish close linkage of the XLA locus to the DXS17 restriction fragment length polymorphic (RFLP) marker locus (the lod score exceeding 6 at phi = 0). A series of RFLP markers around the DXS17 locus provided an RFLP haplotype of use in genetic counselling within this pedigree. In one other pedigree a phenotypically identical disease was inherited but was accompanied by a high frequency of recombination with the DXS17 locus, which made localisation of the gene at the DXS17 locus highly unlikely (lod score less than -3). This genetic heterogeneity complicates genetic counselling within particular pedigrees, especially when the localization of the XLA gene involved in those pedigrees has not been established. 相似文献
6.
Zhang X Liu Q Chen B Guo C Li J Gao G Guo Y Gong Y 《American journal of medical genetics. Part A》2004,(3):286-289
By using several microsatellite markers scattered along the X chromosome, we studied a Chinese family with nonspecific X-linked mental retardation (MRX84) to search for a region including the MRX84 locus that was linked to the markers. Two-point linkage analysis demonstrated linkage between the disorder and several markers located at Xq22.2, with maximum LOD score Z(max) = 2.41 at recombination fraction theta = 0 for DXS1191 and DXS1230, respectively. Recombination events were observed with flanking markers DXS8080 and DXS456, located at Xp11.3 and Xq22.3, respectively, and a region of approximately 22.3 cM was defined. Accordingly, markers distal to Xp11.3 and Xq22.3 segregated independently of the disease. The localized region observed in this Chinese family overlaps with 29 other MRX loci previously reported in Xp11.3-q22.3. These results should contribute to the identification of the disease gene for the MRX84 disorder. 相似文献
7.
N. Dahl M. Sundvall U. Pettersson S. Andréasson M. Anvret U. Kugelberg A. Hagbyhn-Gericke P. Goonewardena 《Clinical genetics》1991,40(6):435-440
Linkage analysis was performed in three Swedish families segregating for X-linked retinitis pigmentosa (XLRP), using five polymorphic DNA markers assigned to Xp. Individual recombination events were analyzed and two- and five-point linkage analysis was undertaken. In one family, a XLRP locus was mapped to the same position as OTC corresponding to RP3. In two families, a disease locus linked to OTC was excluded. In one family, recombination events indicate a locus for XLRP outside the interval (DXS84-OTC-DXS255-DXS14), most likely on the centromeric side of DXS14. 相似文献
8.
Extragenic factor IX gene RFLP is useful for detecting carriers of Japanese hemophilia B 总被引:1,自引:0,他引:1
M Tanimoto T Kojima K Ogata M Hamaguchi J Takamatsu T Kamiya H Saito 《Journal of Japan Haematological Society》1989,52(4):774-777
Seventy-eight X chromosomes from 25 normal Japanese subjects and 22 family members with hemophilia B (coagulation factor IX deficiency) were examined with an extragenic factor IX DNA probe, pX58dIIIc at DXS99 locus. In contrast to the previously described nonpolymorphic RFLPs in the factor IX gene, DXS99 locus RFLP produced by SacI digestion was detected among those Japanese subjects with allelic frequencies of 0.48 and 0.52. The estimated heterozygosity rate of this extragenic RFLP among Japanese females was about 50%. The study of hemophilia B family members showed that DXS99 locus RFLP was informative in 9 out of 13 families tested (69.2%). No recombination events between the factor IX gene locus (F9) and DXS99 locus have been noted among nine families analyzed. DXS99 SacI RFLP is a useful gene indicator of carrier-ship of hemophilia B. 相似文献
9.
Ahmad W Noci S Faiyaz ul Haque M Sarno T Aridon P Ahmad MM Amin-Ud-Din M Rafiq MA ul Haque S De Fusco M Ballabio A Franco B Casari G 《American journal of medical genetics》2001,100(1):62-65
Nonspecific X-linked mental retardation is a nonprogressive, genetically heterogeneous condition that affects cognitive function in the absence of other distinctive clinical manifestations. We report here linkage data on a large Pakistani family affected by a form of X-linked nonspecific mental retardation. X chromosome genotyping of family members and linkage analysis allowed the identification of a new disease locus, MRX53. The defined critical region spans approximately 15 cM between DXS1210 and DXS1047 in Xq22.2-26. A LOD score value of 3.34 at no recombination was obtained with markers DXS1072 and DXS8081. 相似文献
10.
X X Gu R Decorte P Marynen J P Fryns J J Cassiman P Raeymaekers 《Journal of medical genetics》1996,33(1):52-55
Non-specific mental retardation (MR) is a condition in which MR appears to be the only consistent manifestation. The X linked form (MRX) is genetically heterogeneous. We report clinical, cytogenetic, and linkage data on a family with X linked non-specific MR. Two point and multi-point linkage analysis with 18 polymorphic markers, covering the entire chromosome, showed close linkage to DXS1001 and DXS425 with a maximal lod score of 2.41 at 0% recombination. DXS178 and the gene for hypoxanthine phosphoribosyl-transferase (HPRT), located in Xq22 and Xq26 respectively, flank the mutation. All other chromosomal regions could be excluded with odds of at least 100:1. To our knowledge there is currently no other non-specific MR gene mapped to this region. Therefore, the gene causing MR in this family can be considered to be a new, independent MRX locus (MRX35). 相似文献
11.
Wasim Ahmad Sara Noci Mohammad Faiyaz ul Haque Tiziana Sarno Paolo Aridon M. Maqbool Ahmad Muhammad Amin‐ud‐din Muhammad Arshad Rafiq Saeed ul Haque Maurizio De Fusco Andrea Ballabio Brunella Franco Giorgio Casari 《American journal of medical genetics. Part A》2001,100(1):62-65
Nonspecific X‐linked mental retardation is a nonprogressive, genetically heterogeneous condition that affects cognitive function in the absence of other distinctive clinical manifestations. We report here linkage data on a large Pakistani family affected by a form of X‐linked nonspecific mental retardation. X chromosome genotyping of family members and linkage analysis allowed the identification of a new disease locus, MRX53. The defined critical region spans approximately 15 cM between DXS1210 and DXS1047 in Xq22.2–26. A LOD score value of 3.34 at no recombination was obtained with markers DXS1072 and DXS8081. © 2001 Wiley‐Liss, Inc. 相似文献
12.
Linkage analysis of two Canadian families segregating for X linked spondyloepiphyseal dysplasia.
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L E Bernard D Chitayat R Weksberg M I Van Allen S Langlois 《Journal of medical genetics》1996,33(5):432-434
X linked spondyloepiphyseal dysplasia (SED) is caused by a growth defect of the vertebral bodies leading to characteristic changes in the vertebral bodies and a short trunk. The gene responsible for this disorder has previously been mapped to Xp22, with a maximum likelihood location between markers DXS16 and DXS92. We present linkage data using microsatellite markers on two Canadian X linked SED families, one of Norwegian descent and the other from Great Britain. In the Xp22 region, three recombination events have occurred in these families, two between markers DXS996 and DXS1043 and one between DXS999 and DXS989. One family shows a maximal lod score of 3.0 at theta = 0 with marker DXS1043 and the other family has a maximal lod score of 1.2 at theta = 0 with markers DXS1224 and DXS418. Both families therefore support the previously reported gene localisation. 相似文献
13.
目的 改进DXS52(St14)在血友病甲(hemophilia A,HA)基因连锁分析中的实验方法并应用于基因诊断,报道DXS52位点与FⅧ基因发生重组的2个家系.方法 采用PCR和琼脂糖凝胶电泳对61个非倒位HA家系的DXS52位点进行基因检测,并用FⅧ基因内的Bcl Ⅰ、HindⅢ、Xba Ⅰ、STRl、STRl3、STR22和STR24这7个位点以及DXS52位点对这61个家系进行基因连锁分析.结果 DXS52位点在43个HA家系中可提供信息,可诊断率为70.5%(43/61).其中8个家系仅DXS52单个位点能提供信息,占13.1%;两个家系的DXS52与FⅧ基因发生基因重组.结论 采用新的实验条件可使DXS52位点基因检测得到准确清晰的实验结果.该位点可诊断率高,目前是HA连锁基因分析中不可缺少的诊断位点,但该位点位于FⅧ基因外,与FⅧ基因间存在重组可能,单独应用于诊断时应谨慎.Abstract: Objective To improve the experimental method of DXS52 (St14) and apply it to genetic testing for hemophilia A (HA). Methods PCR of DXS52 and agarose gel electrophoresis were performed for genetic testing in 61 non-inversion HA families. Linkage analysis of 7 loci within the FⅧ gene including Bcl Ⅰ , Hind Ⅲ, Xba Ⅰ , STR1, STR13, STR22 and STR24 were also carried out for the 61 families.Results DXS52 can provide information in 43 out of 61 families and the diagnostic rate was 70. 5%. Eight families can be diagnosed only by DXS52 locus, accounting for 13. 1%. Two families were found to have recombination between DXS52 and FⅧ. Conclusion The new experimental conditions can reach accurate and clear results in DXS52 genetic testing. This gene maker has high diagnostic rate, so it is an indispensable linkage analysis method in HA gene diagnosis. More caution should be paid when using the extragenic locus DXS52 to perform gene diagnosis because of its high recombinant rate with FⅧ. 相似文献
14.
L B Jemaa V des Portes R Zemni R Mrad F Maazoul C Beldjord H Chaabouni J Chelly 《American journal of medical genetics》1999,85(3):276-282
Nonspecific X-linked mental retardation (MRX) is a heterogeneous condition in which mental retardation (MR) appears to be the only consistent manifestation. A large genetic interval of assignment obtained on individual families by linkage analysis, genetic, heterogeneity, and phenotypic variability usually are major obstacles to fine-map and identify the related disease genes. Here we report on a large Tunisian family (MRX54) with an MRX condition. X-linked recessive inheritance is strongly suggested by the segregation of MR through seven unaffected carrier females to 14 affected males in two generations. Two-point linkage analysis demonstrated significant linkage between the disorder and several markers in Xp21.3-22.1 (maximum LOD score Zmax = 3.56, recombination fraction 0 = 0 at DXS1202), which was confirmed by multipoint linkage analyses. Recombinant events observed with the flanking markers DXS989 and DXS1218 delineate a refined locus of approximately 2.7 cM in accordance with the physical distance between these two markers. The small interval of assignment observed in this family overlaps not only with nine large MRX loci previously reported in Xp21.3-22.1 but also with two inherited microdeletions in Xp21.3-22.1 involved in nonspecific MR. Although the involvement of several genes located in the Xp21.3-22.1 region cannot be ruled out, data reported in this study could be used as a starting point for the search of such gene(s). 相似文献
15.
A Watty F Prieto M Beneyto M Neugebauer A Gal 《American journal of medical genetics》1991,38(2-3):234-239
A mapping study was performed on a 3-generation Spanish family with X-linked syndromal mental retardation. Affected males have a typical facial appearance, ear malformations, abnormal growth of teeth, clinodactyly, dimpled skin at the lower back, and patellar luxation. In pneumoencephalography a marked subcortical cerebral atrophy was evident. In the linkage studies with polymorphic DNA markers, no recombination was found between the disease locus and the loci OTC and DXS148, both assigned to Xp21.1. One or more recombinants were observed between the disease locus and loci from the distal part of Xp and the pericentromeric region. Close linkage to loci of Xq has also been excluded. The analysis of multiple informative meioses suggests that the disease locus maps between DXS255 (Xp11.22) and DXS84 (Xp21.1) on Xp. 相似文献
16.
Bridging markers defining the map position of X linked hypophosphataemic rickets. 总被引:11,自引:0,他引:11
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R V Thakker A P Read K E Davies M P Whyte R Weksberg F Glorieux M Davies R C Mountford R Harris A King et al. 《Journal of medical genetics》1987,24(12):756-760
Hypophosphataemic rickets is commonly an X linked dominant hereditary disorder associated with a renal tubular defect in phosphate transport and bone deformities. The gene causing this disorder has been mapped to Xp22.31----p21.3 by using cloned human X chromosome sequences identifying restriction fragment length polymorphisms (RFLPs) in linkage studies of affected families. The hypophosphataemic rickets gene locus (HPDR) was previously mapped distal to the X linked polymorphic locus DXS41 (99.6) but its position in relation to the distal loci DXS43 (D2) and DXS85 (782) was not established. In order to obtain a precise mapping of the disease locus in relation to these genetic loci, additional affected families informative for these X linked markers have been investigated. The combined results from the two studies have established linkage with the loci DXS41 (99.6) and DXS43 (D2); peak lod score for DXS41 (99.6) = 7.35, theta = 0.09, and peak lod score for DXS43 (D2) = 4.77, theta = 0.16. Multilocus linkage analysis mapped the hypophosphataemic rickets gene distal to the DXS41 (99.6) locus and proximal to the DXS43 (D2) locus, thereby revealing two bridging genetic markers for the disease. 相似文献
17.
X-linked myotubular myopathy: a linkage study 总被引:4,自引:0,他引:4
Catarina Darnfors H. E. Börje Larsson Anders Oldfors Mårten Kyllerman Karl-Henrik Gustavson Gunnar Bjursell Jan Wahlström 《Clinical genetics》1990,37(5):335-340
Two families with the congenital X-linked infantile form of myotubular myopathy have been investigated by linkage analysis using markers from the X-chromosome. Linkage was found at the locus Xq28 (with DXS52). The analysis gave a peak lod score of 2.41 at the recombination fraction zero. Free recombinations (theta = 0.50) were seen using the markers DXS84, DXS14 and DXS146 from the p arm of the X-chromosome. Since the disorder is very rare, it is important to add cumulative linkage data from the few families that do exist. 相似文献
18.
Bakary S. Sylla Qing Wang Daniel Hayoz G. Mark Lathrop Gilbert M. Lenoir 《Clinical genetics》1989,36(6):459-462
We have performed, in a large Swiss family, a study of linkage between various DNA markers in the Xq24-27 region and the locus for the X-linked lymphoproliferative syndrome (XLP). Our results indicated that the marker DXS37 in Xq25-q26 is genetically linked to the XLP syndrome. The multipoint linkage analysis showed that the disease locus is distal to DXS11, but proximal to the hypoxanthine phosphoribosyl-transferase gene (HPRT). 相似文献
19.
Linkage mapping of a large Colombian family segregating for X linked retinoschisis: refinement of the chromosomal location.
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B S Shastry J F Hejtmancik A Rodriguez F Rodriguez M L Tamayo 《Journal of medical genetics》1997,34(6):504-506
Juvenile X linked retinoschisis (RS) is a bilateral vitreoretinal dystrophy that develops early in life. Previous linkage studies have localised the RS gene to Xp22.1-p22.3 between DXS207 and AFM 291Wf5, which represents a genetic distance of approximately 3.7 cM. In an effort to facilitate the eventual cloning of the RS gene, we have analysed a large Colombian family, using 10 microsatellite markers that have been mapped to the region Xp22.1-p22.3. A total of 93 members, including 19 affected and eight unaffected males, two affected females, and six obligate carrier females were analysed. Close linkage was observed between the disease locus and DXS999 (Zmax = 2.27, theta max = 0.05), DXS987 (Zmax = 2.61, theta max = 0.1), DXS443 (Zmax = 4.23, theta max = 0.1), and DXS274 (Zmax = 3.49, theta max = 0.05) markers. Recombination with the RS locus was found for all marker loci except DXS197, DXS43, and DXS1195. These results place the RS locus within an interval of approximately 2 cM between the flanking markers DXS1053 and DXS999, approximately 1.7 cM closer than the previously reported boundary. The results also further confirm the lack of genetic heterogeneity of RS. 相似文献