Chromosomal fragile sites in schizophrenic patients

Schizophrenia is a common and complex mental disorder. Cytogenetic and molecular studies have shown that genetic factors play an important role in the etiology of schizophrenia. As a preliminary step in the search for chromosomal location of a susceptible gene predisposing to schizophrenia, cytogenetic screening of patients might be useful. Therefore, this report is aimed at studying the relationship between chromosomal fragile sites (FS) (gaps, breaks, triradial figures, and several rearrangements) and the etiology of schizophrenia. Because of this, we compared the frequencies of folate-sensitive FS from schizophrenic patients and normal individuals in short-term whole-blood cultures. The rate of FS expression in the patients was considerably higher than in the controls. We determined 15 common FS (cFS) (1q21, 1q32, 2q21, 2q31, 3p14, 4q31, 5q31, 6q21, 6q26, 7q22, 7q32, 10q22, 13q32, Xp22, and Xq22), six rare FS (rFS) (6p21, 8q22, 11q23, 12q24, 16q22, and Xq26), and two previously unknown FS (3p25 and 5q22). Among these expressed FS, there was a significantly higher frequency of 12 FS at 2q31, 3p25, 3p14, 5q31, 6q21, 7q22, 7q32, 10q22, 11q23, 12q24, Xq22, and Xq26 in patient group than in controls by x ²-test (P between 0.0001 to 0.036). Sites 3p14, 5q31, and 7q22 were also the most frequently observed cFS. Males exhibited twice as many FS as females, but no age effects were observed. The potential relationship between increased FS frequency and the occurrence of schizophrenia in these patients is discussed. The text was submitted by the authors in English.     

Genomic imbalances in esophageal squamous cell carcinoma identified by molecular cytogenetic techniques

This review summarizes the chromosomal changes detected by molecular cytogenetic approaches in esophageal squamous cell carcinoma (ESCC), the ninth most common malignancy in the world. Whole genome analyses of ESCC cell lines and tumors indicated that the most frequent genomic gains occurred at 1, 2q, 3q, 5p, 6p, 7, 8q, 9q, 11q, 12p, 14q, 15q, 16, 17, 18p, 19q, 20q, 22q and X, with focal amplifications at 1q32, 2p16-22, 3q25-28, 5p13-15.3, 7p12-22, 7q21-22, 8q23-24.2, 9q34, 10q21, 11p11.2, 11q13, 13q32, 14q13-14, 14q21, 14q31-32, 15q22-26, 17p11.2, 18p11.2-11.3 and 20p11.2. Recurrent losses involved 3p, 4, 5q, 6q, 7q, 8p, 9, 10p, 12p, 13, 14p, 15p, 18, 19p, 20, 22, Xp and Y. Gains at 5p and 7q, and deletions at 4p, 9p, and 11q were significant prognostic factors for patients with ESCC. Gains at 6p and 20p, and losses at 10p and 10q were the most significant imbalances, both in primary carcinoma and in metastases, which suggested that these regions may harbor oncogenes and tumor suppressor genes. Gains at 12p and losses at 3p may be associated with poor relapse-free survival. The clinical applicability of these changes as markers for the diagnosis and prognosis of ESCC, or as molecular targets for personalized therapy should be evaluated.     

Population cytogenetics of aphidicolin-induced fragile sites

Summary Chromosome fragile sites are inducible by aphidicolin in cultured human lymphocytes. To assess the frequency and distribution of these common fragile sites in the general population, a cytogenetic survey was performed on 126 subjects, 59 males and 67 females, whose age ranged from 1 day to 72 years. Common fragile sites, induced by aphidicolin, were widespread and showed a remarkably different sensitivity among individuals; age influenced the overall frequency of fragile sites. Moreover, both age and sex seemed to modulate the expression of specific fragile sites. In our population, the most common fragile sites were: 3p14, 16q23, Xp22, 6q26, 1p31, 4q31, 1p22, 7q22, 2q33, 3q27, 2q31, 7q32, 14q24, 10q22, 5q31, 2q37, 6p21.     

Identification of DNA copy-number aberrations by array-comparative genomic hybridization in patients with schizophrenia

Chromosomal abnormalities are implicated as important markers for the pathogenesis in patients with schizophrenia. In this study, with using bacterial artificial chromosome (BAC) array-based comparative genomic hybridization (CGH), we analyzed DNA copy-number changes among 30 patients with schizophrenia. The most frequent changes were partial gain of Xq23 (52%) and loss of 3q13.12 (32%). Other frequent gains were found in: 1p, 6q, 10p, 11p, 11q, 14p, and 15q regions, and frequent losses were found in: 2p, 9q, 10q, 14q, 20q, and 22q regions. The set of abnormal regions was confirmed by real-time PCR (9q12, 9q34.2, 11p15.4, 14q32.33, 15q15.1, 22q11.21, and Xq23). All real-time PCR results were consistent with the array-CGH results. Therefore, it is suggested that array-CGH and real-time PCR analysis could be used as powerful tools in screening for schizophrenia-related genes. Our results might be useful for further exploration of candidate genomic regions in the pathogenesis of schizophrenia.     

Expression of common fragile sites in two Ceboidea species: Saimiri boliviensis and Alouatta caraya (Primates: Platyrrhini)

Fragile sites are points of preferential breakage that may be involved in chromosome rearrangements. Induction of common fragile sites (c-fra) and spontaneous breakage were analyzed in two New World Monkeys species: Saimiri boliviensis (SBO) and Alouatta caraya (ACA). Spontaneous chromosome aberrations were analyzed on untreated lymphocyte cultures with Brögger''s formula (1977). SBO presented a low level of spontaneous breakage, while higher frequencies were detected in ACA in which bands 1q23; 2q13 and 11q19 were significantly affected (p < 0.01). The populational distribution of c-fra was analyzed by the Chi² test in FUdR plus caffeine treated cultures. A total of 21 c-fra was identified in SBO and 24 in ACA. Fragile sites A₁q33, B₁p21, B₄p14, C₃q23 and C₅q22 were identified in all analyzed SBO specimens. The most frequent c-fra identified in ACA specimens were 1q23, 1q31, 1q33, 2q22, 8q14, 12q31, 13q22, 14q15 and Xq22. Fragile sites A₁q31, A₁q33, B₁q14, B₃q13, B₄q21 and Xq22 identified in SBO and 1q31, 1q33, 2q22, 4q21, 6q13, 13q22 and Xq22 from ACA were the most conserved sites. A low coincidence between the location of c-fra and that of heterochromatin and breakpoints involved in euchromatic rearrangements known for these genera, was established.     

Molecular cytogenetic analysis of follicular lymphoma (FL) provides detailed characterization of chromosomal instability associated with the t(14;18)(q32;q21) positive and negative subsets and histologic progression

We analyzed a cohort of 61 follicular lymphomas (FL) with an abnormal G-banded karyotype by spectral karyotyping (SKY) to better define the chromosome instability associated with the t(14;18)(q32;q21) positive and negative subsets of FL and histologic grade. In more than 70% of the patients, SKY provided additional cytogenetic information and up to 40% of the structural abnormalities were revised. The six most frequent breakpoints in both SKY and G-banding analyses were 14q32, 18q21, 3q27, 1q11-q21, 6q11-q15 and 1p36 (15-77%). SKY detected nine additional sites (1p11-p13, 2p11-p13, 6q21, 8q24, 6q21, 9p13, 10q22-q24, 12q11-q13 and 17q11-q21) at an incidence of >10%. In addition to the known recurring translocations, t(14;18)(q32;q21) [70%], t(3;14)(q27;q32) [10%], t(1;14)(q21;q32) [5%] and t(8;14)(q24;q32) [2%] and their variants, 125 non-IG gene translocations were identified of which four were recurrent within this series. In contrast to G-banding analysis, SKY revealed a greater degree of karyotypic instability in the t(14;18) (q32;q21) negative subset compared to the t(14;18)(q32;q21) positive subset. Translocations of 3q27 and gains of chromosome 1 were significantly more frequent in the former subset. SKY also allowed a better definition of chromosomal imbalances, thus 37% of the deletions detected by G-banding were shown to be unbalanced translocations leading to gain of genetic material. The majority of recurring (>10%) imbalances were detected at a greater (2-3 fold) incidence by SKY and several regions were narrowed down, notably at gain 2p13-p21, 2q11-q21, 2q31-q37, 12q12-q15, 17q21-q25 and 18q21. Chromosomal abnormalities among the different histologic grades were consistent with an evolution from low to high grade disease and breaks at 6q11-q15 and 8q24 and gain of 7/7q and 8/8q associated significantly with histologic progression. This study also indicates that in addition to gains and losses, non-IG gene translocations involving 1p11-p13, 1p36, 1q11-q21, 8q24, 9p13, and 17q11-q21 play an important role in the histologic progression of FL with t(14;18)(q32;q21) and t(3q27).     

Expression of folate-sensitive fragile sites in lymphocyte chromosomes

Summary The expression of folate-sensitive fragile sites (FS) was analyzed using MTX as a fragility inducer in seven normal subjects [four unrelated persons and three members of one family (father, mother, and son)]; a woman heterozygous for fra Xq27.3 with a 47,XXX karyotype; and her son, affected by the fra-X syndrome. The mean expression of chromosome lesions (CL) other than Xq27.3 was 70.1% (686CL in 978 metaphases), and the coincidence between CL and FS was 68.9%. We propose six new c-fra sites: bands 4q33 and 11q22 because they were found in two members of the same family; band 13q32 because it had a frequency of expression of 3% of metaphases; and bands 3p13, 8q21, and Xq21 because they were observed in four of the nine individuals studied.     

Thirteenfold increase of chromosomal aberrations non-randomly distributed in chagasic children treated with nifurtimox

Chromosomal aberrations were analyzed from cultures of peripheral lymphocytes in 2 groups of chagasic children, before and after treatment with nifurtimox. The mean incidence of chromosomal aberrations increased from control values of 1.75 +/- 1.39 (8 patients) to 23.55 +/- 9.55 (6 patients) at a significance of P less than 0.0001. G-banding analysis of chromosomal aberration sites revealed that treated patients present coincidence in the chromosome regions affected: 1p11, 1q11-12, 9q11-13, 17q11-21, 2p21, 2q23, 2q31, 2q33, 6p21, 6p21, 7q32, 13q14, 13q22, 15q22. These data indicate a non-random distribution of chromosomal aberrations induced by nifurtimox therapeutic treatment.     

Thirteen type I loci from HSA4q, HSA6p, HSA7q and HSA12q were comparatively FISH-mapped in four river buffalo and sheep chromosomes

Thirteen goat BAC clones containing coding sequences from HSA7, HSA12q, HSA4 and HSA6p were fluorescence in situ mapped to river buffalo (Bubalus bubalis, BBU) and sheep (Ovis aries, OAR) R-banded chromosomes. The following type I loci were mapped: BCP to BBU8q32 and OAR4q32, CLCN1 to BBU8q34 and OAR4q34, IGFBP3 to BBU8q24 and OAR4q27, KRT to BBU4q21 and OAR 3q21, IFNG to BBU4q23 and OAR3q23, IGF1 to BBU4q31 and OAR3q31, GNRHR to BBU7q32 and OAR6q32, MTP to BBU7q21 and OAR6q15, PDE6B to BBU7q36 and OAR6q36, BF to BBU2p22 and OAR20q22, EDN1 to BBU2p24 and OAR20q24, GSTA1 to BBU2p22 and OAR20q22, OLADRB (MHC) to BBU2p22 and OAR20q22. All mapped loci appeared to be located on homologous chromosomes and chromosome bands in both bovids. Comparison between gene orders in bovid (BBU and OAR) and human (HSA) chromosomes revealed complex rearrangements, especially between BBU7/OAR6 and HSA4, as well as between BBU2p/OAR20 and HSA6p.     

Nonrandom distribution of methotrexate-induced aberrations on human chromosomes. Detection of further folic acid sensitive fragile sites

Summary Eleven folic acid sensitive fragile sites (3p14, 7p13, 7q31.1, 7q32, 9q32, 11p13, 14q23, 15q22, 16q23, Xp22.2, Xq22) were detected in one individual, eight of them previously unknown. These sites seem to bear each its specific sensitivity to folic acid deficiency. Six of the sites were observed simultaneously on both homologous chromosomes in at least one cell. Each of these 11 sites was also found in at least one among 12 individuals further examined. Some of these individuals showed six of these 11 sites. The fragile site 3p14 was detected in all individuals examined. The homologous sites 3p14 of one individual differed from each other in their frequency of lesions induced by methotrexate as well as fluorodeoxyuridine. This observation suggests that folic acid sensitivity is a property inherent in the chromatin of an individual chromosome at the site involved in fragility. This property seems to be responsible for the nonrandom fragility at that site and also for the individual sensitivity of each chromosomal site.     

Synergistic effect of DAPI and thymidylate stress conditions on the induction of common fragile sites

When supplied to human leukocytes grown in complete medium (RPMI 1640), DAPI, a nonintercalating compound specific for the AT bases of DNA, induces the appearance of three common fragile sites (CFRA) mapped at 1q42, 2q31, and 7p22. The same treatment with DAPI in a medium deficient in folic acid and thymidine (199 M) considerably increases the expression of these sites and induces the appearance of a further 16 CFRA sites at 1q24, 2p25, 4p16, 4q25, 5p15.3, 6p21.3, 6p25, 6q13, 9p24, 16p13.3, 16q23, 17q21, 18q23, 20q13.1, 21q21, and Xq28. The results point to the existence of a synergism between DAPI and thymidylate-stress culture conditions in inducing site-specific chromosome damage. The results also agree with the hypothesis that DAPI-induced CFRA sites are DNA late-replicating chromosomal areas rich in AT bases.     

Expression of aphidicolin, FUdR and caffeine‐induced fragile sites in lymphocytes of healthy Turkish individuals

The expression of common fragile sites (c‐fra) and frequency of chromosomal aberrations were studied in peripheral lymphocytes of 50 healthy Turkish individuals (26 males and 24 females from 1 to 87 years of age) after induction with aphidicolin (APC), 5′‐fluorodeoxyuridine (FUdR), and caffeine. A correlation was seen between age and the frequency of chromosomal aberrations in APC and caffeine treated cultures, but there were no significant differences in the frequencies of chromosomal aberrations between males and females in any of the treatments. The mean frequency of aberrations induced by FUdR was significantly higher than that induced by APC and caffeine. A chromosome aberration is defined as a fragile site when present in 1% of the cells analyzed from each culture and in at least 50% of the individuals studied. Using these criteria, 12 c‐fra were observed in the three treatments: 1p21, 1q21, 2p11‐q11, 3p14, 4q31, 6q26, 7q22, 7q32, 8q24, 11q23, 16q23, and Xp22. Sites 3p14, 16q23, and Xp22 were the most frequently observed c‐fra, with only the frequency of Xp22 being significantly increased in females in APC treated cultures. The results of these studies are important as a base against which the effects of other clastogenic and environmental agents, as well as genetic background, can be compared. This revised version was published online in July 2006 with corrections to the Cover Date.     

Human chromosome hot points

Summary Peripheral lymphocytes from 16 healthy adults, 9 pregnant women, and 3 fragile X syndrome patients were cultured in Eagle's minimum essential medium without folic acid (MEM-FA). The addition of 2mM, 4mM, or 8mM uridine 24h or 72h prior to harvest resulted in increases of chromosome gaps or breaks, especially at hot points 3p14, 16q23-24, and at fragile site Xq27. Pregnant women showed higher frequencies of 3p14 breaks and total chromosome breaks than men and non-pregnant women. The other chromosome regions, such as 6q26, 7q23, 7q35, 6p25, Xp22, 14q23 and 11p13, also frequently showed gaps or breaks. The results indicated that the unbalance of nucleotide pools was one of the causes of chromosome breakages. The higher frequencies of chromosome gaps and breaks under the condition of thymidylate stress may be due to the misincorporation of uracil instead of thymine into DNA.     

131例原发性闭经女性的细胞遗传学分析(含世界首报异常核型3例)

原发性闭经是一种原因复杂的疾病, 染色体异常则是发病的主要原因。通过对131例原发性闭经患者的外周血淋巴细胞染色体的G带核型分析, 发现其中83例为正常女性核型, 占63.36%; 各种异常核型48例,占36.64%, 其中包括3例世界首次报道的异常核型[46,X,t(X;1)(q22;p34); 46,X,t(X;5;6)(p11.2;q35;q16); 46,XX,t(4; 9)(q21;p22),t(6;10)(p25;q25),t(11;14)(q23;q32)]。另外, 将33例Turner’s综合征患者的主要异常体征及核型分布分别与Elsheikh等的报道进行比较, 发现矮身材、蹼颈、后发迹低和肘外翻的发生率与文献资料存在显著差异, 说明东西方Turner’s综合征患者临床体征的表现可能存在差异。通过对2例X-常染色体易位携带者的分析, 认为Xp11.2和Xq22区域可能与原发性闭经有关。     

Preferential loss of 5q14-21 in intestinal-type gastric cancer with DNA aneuploidy

BACKGROUND: Little is known about the genetic changes associated with DNA ploidy in gastric cancer (GC). The aim of this study was to identify recurrent or specific chromosomal regions of DNA sequence copy number aberrations (DSCNAs) that might harbor genes associated with DNA aneuploidy in GC. METHODS: We analyzed DSCNAs with comparative genomic hybridization and DNA ploidy by laser scanning cytometry in 16 primary intestinal-type GCs. RESULTS: All GCs examined showed at least one DSCNA (loss or gain); eight were DNA diploid (DD) tumors and eight were DNA aneuploid (DA) tumors. The frequent (>30%) DSCNAs were loss of 5q14-21 and gains of 7p11-14, 8q, 20q, and Xq25-26. Recurrent amplifications (>10%) were detected at chromosomal regions 6p, 7p, and 13q. The overall number of DSCNAs was significantly greater in DA than in DD tumors (P = 0.006). Furthermore, the number of aberrations was clearly greater with 5q loss than without 5q loss (P = 0.002). Losses of 5q14-21, 9p21-pter, 16q, and 18q21-qter were preferentially detected in DA tumors. CONCLUSION: The present observations indicate that there is a close relationship between DSCNA and DNA ploidy in intestinal-type GC and that gene(s) at 5q14-21, 9p21-pter, 16q, and/or 18q21-qter may play important roles in acquisition of DNA aneuploidy.     

Chromosome assignment of four RAS-related RAB genes

Summary The human RAB genes share structural and biochemical properties with the RAS gene superfamily. The encoded RAB proteins show 38 to 75% amino acid identity with the yeast YPT1 and SEC4 gene products. We used four human RAB-cDNAs, RAB3B, RAB4, RAB5 and RAB6, to map the corresponding genes on human chromosomes. These genes were assigned to 1p32-p31, 1q42-q43, 3p24-p22 and 2q14-q21, respectively, by in situ hybridization.     

16种罕见的人类染色体异常核型报告

通过对患有闭经、自发流产、死胎、死产等患者外周血淋巴细胞染色体检查,发现16种新的罕见人类染色体异常核型,它们是46,XY,t(6;11)(q25;p15);46,XY,inv(3)(p25;q29);46,XY,t(7;18)(q10;p10);46,X,t(X;13)(q24;q14);46,XY,t(4;7)(q33;q22);46,XY,t(8;15)(q24;q15);46,XY,t(2;17)(q33;q25);46,XX,t(4;7)(q34;q11);46,XX,t(1;3)(p36;p23);46,XX,t(4;6)(q35;p11);46,X,inv(X)(q22;q28);46,XX,t(7;10)(p11;q26);46,XX,t(3;6)(p21;q23);46,XX,t(8;16)(p21;p13);46,XX,t(8;9)(q21;q34);46,XY,t(17;22)(q21;q11)。描述了患者的临床表现,并对生殖异常患者染色体畸变与其表型效应关系进行探讨。Abstract：By examining the lymphocytic chromosomes of peripheral blood from patients with amenorrhea,spontaneous abortion and stillbirth history, .the 16 rare species of human chromosomal abnormal karyotypes were discovered. They wre 46,XY,t(6;11)(q25;p15);46,XY,inv(3)(p25;q29);46,XY,t(7;18)(q10;p10);46,X,t(X;13)(q24;q14);46,XY,t(4;7)(q33;q22);46,XY,t(8;15)(q24;q15);46,XY,t(2;17)(q33;q25);46,XX,t(4;7)(q34;q11);46,XX,t(1;3)(p36;p23);46,XX,t(4;6)(q35;p11);46,X,inv(X)(q22;q28);46,XX,t(7;10)(p11;q26);46,XX,t(3;6)(p21;q23);46,XX,t(8;16)(p21;p13);46,XX,t(8;9)(q21;q34);46,XY,t(17;22)(q21;q11). Their clinical situation were described. Discussion on the relationship between the chromosomal aberrations and phenotype effect indicates the importance of chromosome karyotyping in patients with abnormal reproductive history.