X Chromosome Research Articles

Replacement of androgen receptor gene causes complete androgen insensitivity in a large family

To confirm the clinical diagnosis of complete androgen insensitivity syndrome (CAIS) by molecular genetic testing in a large family. PCR was performed to amplify the coding region of androgen gene, followed by direct sequencing in the patients with CAIS and relatives in this family. A missense mutation Arg773His was identified in the patients (homozygous) and carriers (heterozygous). Mutation Arg773His in the AR gene leads to CAIS in this family. Molecular genetic testing of CAIS facilitates not only prenatal genetic diagnosis but also preimplantation genetic diagnosis and offers genetic counseling for future pregnancies to abandon the transmission of the mutated X chromosome to the coming generation.

Genetic analysis of 62 patients with abnormal X chromosome

目的 分析X染色体异常者的遗传学特征.方法 常规方法对我室1992～2007年共4638例患者行外周血培养,收获中期淋巴细胞制片,G显带,进行染色体核型分析.结果 4638例中检出X染色体异常62例,其中X数目异常48例,X结构异常14例.结论 对有体格、性腺、智力发育异的人群进行细胞遗传学检查能更好的为患者提供临床治疗依据及生育指导。

Clonality and Ki-67 protein expression in gastric carcinoma and precancerous lesions

To study the clonality of gastric carcinoma and precancerous lesions and its relationship with Ki-67 protein expression. Formalin-fixed paraffin embedded tissues were collected from 174 cases of gastric endoscopic biopsies and surgical removed specimens. The lesional tissues were isolated by Laser Capture Microdissection. Methylation sensitive restriction enzyme (HpaII) digestion and polymerase chain reaction (PCR) were used to detect the clonality at the polymorphic human androgen receptor gene locus on the X chromosome. PCR products were analyzed by capillary electrophoresis using applied Biosystems 3730 DNA Analyzer. In addition, a two-step immunohistochemical staining EnVision method was used to detect the expression of Ki-67 protein. The frequency of detection of monoclonality and expression rate of Ki-67 were found increased in a stepwise fashion from gastrointestinal metaplasia, low grade intraepithelial neoplasia, high grade intraepithelial neoplasia to intestinal carcinoma (15.63%, 5/32; 22.22%, 10/45; 69.44%, 25/36 and 100.0%, 20/20; respectively). The presence of clonal proliferation was correlated with Ki-67 expression in low grade intraepithelial neoplasia (P < 0.01). The presence of clonal proliferation and increased Ki-67 are increasingly detected in the lesions along the multi-step gastric carcinogenesis model. Clonal status is associated with the expression rate of Ki-67 to a certain extent, suggesting a combined application of both markers may be useful in assessing early stages of gastric carcinoma.

X chromosome drive

I'd like to thank Catherine Montchamp-Moreau and Yun Tao for helpful comments on the manuscript.

Utility of X-chromosome SNPs in relationship testing

X-chromosome markers may complement the results obtained from other genetic markers in complex relationship cases. Until now, reports on relationship testing using X-chromosome markers have mainly included data of short tandem repeats (STRs) while little data on single nucleotide polymorphisms (SNPs) in relationship testing have been published. We selected 25 highly polymorphic biallelic SNPs distributed through the human X-chromosome. One 25-plex PCR reaction and one 25-plex single base extension (SNaPshot) reaction were developed. The maximum size of the PCR products was 120 bp and the size of the SBE primers varied between 18 and 85 nucleotides. We analyzed the allele and haplotype frequencies in 1078 unrelated males. All the SNPs were polymorphic and the lowest minor allele frequency was 0.103. All the haplotypes were unique. The forensic parameters were calculated in the Danish and Somali populations. In the Danish population ( N = 93), the power of discrimination (PD) in females was one in 4.4 × 10 9 individuals and the PD in males was one in 2.6 × 10 6. The PD in Somalis ( N = 91) was one in 2.7 × 10 9 in females and one in 1.7 × 10 6 in males. Finally, we present an example of how the 25 X-chromosome SNP-multiplex may help to solve a complex immigration case.

Hyperacetylated Histones Distribution on Chromosome X During Spermiogenesis.

Hyperacetylated Histones Distribution on Chromosome X During Spermiogenesis.

Longitudinal evaluation of expression of virally delivered transgenes in gerbil cone photoreceptors

Delivery of foreign opsin genes to cone photoreceptors using recombinant adeno-associated virus (rAAV) is a potential tool for studying the basic mechanisms underlying cone based vision and for treating vision disorders. We used an in vivo retinal imaging system to monitor, over time, expression of virally-delivered genes targeted to cone photoreceptors in the Mongolian gerbil (Meriones unguiculatus). Gerbils have a well-developed photopic visual system, with 11-14% of their photoreceptors being cones. We used replication deficient serotype 5 rAAV to deliver a gene for green fluorescent protein (GFP). In an effort to direct expression of the gene specifically to either S or M cones, the transgene was under the control of either the human X-chromosome opsin gene regulatory elements, i.e., an enhancer termed the locus control region (LCR) and L promoter, or the human S-opsin promoter. Longitudinal fluorescence images reveal that gene expression is first detectable about 14 days post-injection, reaches a peak after about 3 months, and is observed more than a year post-injection if the initial viral concentration is sufficiently high. The regulatory elements are able to direct expression to a subpopulation of cones while excluding expression in rods and non-photoreceptor retinal cells. When the same viral constructs are used to deliver a human long-wavelength opsin gene to gerbil cones, stimulation of the introduced human photopigment with long-wavelength light produces robust cone responses.

Allelic dropout of amelogenin gene on X chromosome

Objective To investigate the mechanism that cause allelic dropout of amelogenin gene on X chromosome(Amel-X)when using routine Sullivan106/112 bp primer set in sex identification and discuss its influence on the forensic sex identification and the clinical diagnosis.Methods Amel-X dropout was validated with Sullivan212/218 bp and Haas-Rochholz80/83 bp primer sets.Amplification of amelogenin gene was used to analyze dropout of the Amex-X followed by sequencin.Results Sullivan212/218 bp and Hgas-Rochholz80/83 bp primer sets could be used to identify gender correctly.Three types of point mntation were observed in the forward primer binding region of the Sullivan106/112 bp primer set by sequencing in the lost Amel-X,including single point mutation at 2nd and 13th sites,respectively,and heterozygous multiple point mutations at 2nd and 13th sites.Conclusions Point mutation in the primer binding region may result in a failure to amplify amelogenin allele and thus lead to a null allele.This finding should be mid attention to because it may interfere with the sex identification. Key words: X chromosome; Dental enflmel proteins; Loss of heterozygosity; Mutation

Clonal origin of spontaneous multiple mammary tumors in mice with cellular mosaicism.

The clonal origin of spontaneous multiple mammary tumors in mice was examined. For this purpose, hybrid female mice (Pgk-1b/Pgk-1a), F1[SHN(Pgk-1b) X C3H/He (Pgk-1a)], with X-chromosome inactivation mosaicism with regard to the phosphoglycerate kinase (PGK)-1 isozyme together with a high incidence of spontaneous mammary tumors were constructed. Thirty-seven of 45 mammary tumors (82%) in mosaic mice had a single phenotype of PGK, indicating monoclonal origin. The multiple mammary tumors formed in these mice varied in PGK type, indicating independent cellular origins.

WITHDRAWN: The Mediterranean basin: A population genetic study based on 25 X-chromosome SNPs

C. Tomas, J.J. Sanchez, A. Barbaro, C. Brandt-Casadevall, A. Hernandez, B.D. Mohamed, M.M. Ramon, N. Morling Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health Sciences, University of Copenhagen, 11 Frederik V's Vej, DK-2100 Copenhagen, Denmark Instituto Nacional de Toxicologia y Ciencias Forenses, Delegacion de Canarias, Tenerife, Spain Sezione di Genetica Forense, Studio Indagini Mediche E Forensi (SIMEF), Reggio Calabria, Italy Institut Universitaire de Medecine Legale, Lausanne, Switzerland Service de Medecine Legale, Hopital Farhat Hached, Sousse, Tunisia Institut Universitari d’Investigacions en Ciencies de la Salut i Laboratori de Genetica, Departament de Biologia, Universitat de les Illes Balears, Palma de Mallorca, Spain

Clonality of the peripheral papilloma and cancerous cells of breast

To study the clonality status of peripheral papilloma (peri-MP), ductal carcinoma in situ (DCIS), and normal tissue of the breast using an assay based on inactivation mosaicism of the length-polymorphic X-chromosomes at the androgen receptor (AR) locus and to explore a reliable way to distinguish the benign and malignant (or pre-malignant) cases judged morphologically. Specimens of breast tissues were obtained from 26 cases of peri-PM, 25 cases of peri-PM with atypical ductal hyperplasia (ADH), and 27 cases pf DCIS, 16 cases of developed canceration, and 20 normal women. DNA was extracted and amplified via nested-PCR with or without previous digestion by the methylation-sensitive restriction endonuclease Hha I. The products were resolved on denaturing polyacrylamide gels and visualized through silver staining. The clonality of these samples was analyzed by showing the lanes. Loss of polymorphism at the AR locus was found in all the cases with DCIS and in 10 cases (10/25, 40.0%) of peri-PM with ADH, indicating the monoclonality of the tumor. Twenty-four cases (92.3%) of the 26 cases with peri-PM and the 20 specimens of normal tissue were shown to be polyclonal. In the 16 cases of developed canceration identical X chromosome inactivation (monoclonal alterations) was observed in the cancer focus, parts of peri-PM with ADH, and the part of DCIS. Normal breast tissue and peri-PM show polyclonality and the peri-PM with ADH shows monoclonality. Clonality analysis may be a useful modality to screen high-risk cases from precancerous lesions or to distinguish between the benign hyperplasia and early carcinoma.

Holocentric chromosomes in meiosis. II. The modes of orientation and segregation of a trivalent

The modes of orientation and segregation of the sex chromosome trivalent X1X2Y in male meiosis of Cacopsylla mali (Psylloidea, Homoptera) were analysed. Males with an X1X2Y sex chromosome system coexist with males displaying a neo-XY system in populations of this species. The fusion chromosome resulting in the formation of a trivalent in meiosis originates from the fusion of an autosome with the neo-Y chromosome. In the majority of metaphase I cells (92.4%) the X1X2Y trivalent showed co-orientation; X1 and X2 chromosomes oriented towards one pole whereas the Y oriented towards the opposite pole. In the rest of the cells (7.6%) the trivalent with subterminal chiasmata was oriented parallel to the equatorial plane. From this orientation the trivalent produced triple chromatids joined together by undivided telomeric parts of chromosomes and hence by sister chromatid cohesion at anaphase I. In the majority of metaphase II cells the orientation of triple chromatids suggested the production of unbalanced gametes. However, in a small number of cells (1.7%) the trivalent showed co-orientation of X1X2 with Y. Both the first division and second division co-orientations, or 94.1% of divisions as a whole, were estimated to yield balanced gametes, containing either X1 and X2 chromosomes or Y chromosome. It was concluded that, since the triple chromatid contained undivided telomere regions at metaphase II, which divided at anaphase II, the orientation of the trivalent with its longitudinal axis parallel to the equatorial plane in metaphase I also represents co-orientation and results in pre-reduction. The existence of post-reductional behaviour of holocentric bivalents and multivalents is discussed.

Clonality study of palmar fibromatosis

To study the clonality of palmar fibromatosis by molecular genetic analysis of X chromosome inactivation pattern at a polymorphic site of human androgen receptor gene (HUMARA). Twelve female cases of palmar fibromatosis were enrolled into this study. Hematoxylin and eosin-stained sections of paraffin-embedded, formalin-fixed tissues were microdissected by laser capture microdissection technology in order to obtain the proliferative spindle cells. Tumor cells isolated from rectal adenocarcinoma in a female patient were used as positive control. The genomic DNAs were extracted with phenol and chloroform, digested with methylation-sensitive restriction endonuclease HpaII, and amplified by polymerase chain reaction (PCR) using primers targeted to a highly polymorphic short tandem repeat of HUMARA. The amplimers were separated on vertical 8% non-denaturing polyacrylamide gels and the patterns were visualized with ethidium bromide stain. The methodology for clonality analysis was validated in the positive control using rectal adenocarcinoma cells. Among the 12 cases studied, PCR amplification failed in 3 samples and 1 sample showed homozygosity which was not suitable for further analysis. Eight samples were successfully amplified and showed a random X chromosome inactivation pattern, suggesting polyclonality in these lesions. Palmar fibromatosis is a polyclonal condition and should be considered as a form of non-neoplasmic fibroblastic proliferation.

Karyotype and male meiosis in Spartocera batatas and meiotic behaviour of multiple sex chromosomes in Coreidae (Heteroptera)

The Coreidae (Heteroptera) have holokinetic chromosomes and during male meiosis the autosomal bivalents segregate reductionally at anaphase I while the sex chromosomes do so equationally. The modal diploid chromosome number of the family is 2n = 21, with a pair of m-chromosomes and an X0/XX sex chromosome system. A 2n = 24/26 (male/female) and an X1X20/X1X1X2X2 sex chromosome system were found in Spartocera batatas (Fabricius). C-banding and fluorescent-banding revealed the presence of AT-rich heterochromatic bands medially located on all the autosomes, and one telomeric band on both the X1 and X2 chromosomes. This banding pattern differed from the telomeric heterochromatin distribution found in most other heteropteran species. The X1 and X2 chromosomes were intimately associated during male meiosis and difficult to recognize as two separate entities. Based on a comparison with the behaviour of sex chromosomes in other coreids and other heteopterans with multiple sex chromosomes it is suggested that the particular behaviour of X1 and X2 chromosomes in coreid species with multiple sex chromosome systems evolved as an alternative mechanism for ensuring the proper segregation of the sex chromosomes during meiosis.

The epigenetics of enamel formation

Amelogenins, a family of enamel extracellular matrix proteins, are abundantly expressed during tooth development. It is produced by the AMELX Xq22 and AMELY Yp11 genes and the level of transcription of AMELY locus appears to be only approximately 10% of amelogenin transcripts. DNA methylation is the major epigenetic mechanism of regulation of gene expression. Many factors can interfere in gene silencing, such as polymorphisms and nutrients and some genes escape inactivation, principally X-linked genes. The large number of genes that escape inactivation, and their non-random distribution on the chromosome X may have implications in abnormalities caused by genes on this chromossome. Defects of dental enamel formation are caused by genetic or environmental factors, including genetic polymorphisms and nutrient intake. However, the relationship between epigenetic and genetic factors in amelogenesis is not known. In this context, DNA methylation might be a promising path to explain not only the mechanisms of AMEL inactivation, but also in pathological situations.

Recommendation for diagnosis and treatment of fabry’s disease in Slovenia

Background: Fabry disease is a rare X-chromosome linked disease. Due to gene mutation, activity of enzyme α galactosidase A is lowered or absent and sphingolipids are deposited in different organ cells. All males with gene mutation are affected but females too, due to X chromosome inactivation, can frequently be affected as well, although usually to a lesser extend. Disease is slowly progressive and there is an early dysfunction of several organs, specially endothelium, kidney, heart and central nervous system, which all leads to early death of the patient. Conclusions: Recently, a specific enzyme replacement therapy, based on recombinant technology, was discovered. Specific therapy is effective and safe. Due to a new therapy there was a need to set objective criteria when to start with enzyme replacement therapy, but also a need to more complex, multidisciplinary approach to those patients. This article is an initial proposal for systematic management of Fabry disease in our country.

LINE-1 Retrotransposition: Impact on Genome Stability and Diversity and Human Disease

LINE-1 Retrotransposition: Impact on Genome Stability and Diversity and Human Disease

The X in sex: how the X chromosome controls our lives by David Bainbridge

The X in sex: how the X chromosome controls our lives by David Bainbridge

Mysteries of the X Chromosome Revealed

Mysteries of the X Chromosome Revealed

Abnormalities of sexchromosome in patients with mental disorders

：Subject To explore thefeatures of the abnormalities of the sex chromatin and the sex chromosome of the patientswith mental disorders. Methods The sex chromatin in the cells of buccal mucous membrane ofthe 2 784 patients with mental disorders were examined by using a blinding and random way.The chromosome karyotypes in peripheral blood were further examined in those whose measureshowed abnormal. The comparison group consisted of 1 069 normal persons.Results Compairedwith the control group,the average frequency of Y chromatin in the male patients [(28.0±6.6)%]and the average frequency of X chromatin in the female patients [(22.3±8.0)%] rosesignificantly ; the average frequency of X chromatin in the female patients of theschizophrenia subgroup and the affective disorder subgroup were higher than that ofneurosis and psychogenic mental disorder subgroup. X chromatins of eight male patientswere positive and the karyotypes of the abnormal X chromosome were 47,XXY in 3 cases and47,XXY/46,XY in 5 cases, the rate of 47,XXY was 7.7 , it rose significantly to the controlgroup. X chromatin of two female patients were negative and the karyotypes of the abnormalX chromosome was 45,X/46,XX, the rate of 45,X was 1.2 ; one female patient had double Xchromatin and the karyotypes of the abnormal X chromosome was 47,XXX/46,XX,there is noabnormal sex chromatin and sex chromosome in the control group.Conclusions The higher rateof the sex chromatin might be closely associated with the tendency of heredity of mentaldisorders , and the rate of the lacking X chromosome in females and the increasing Xchromosome in males rise in the patients with mental disorders. Key words: Sex chromosome; Mental disorders; Klinfelter's syndrome; Turner'ssyndrome