Identification of the chromosome 14 origin of a C-negative marker associated with a 14q32 deletion by chromosome painting

A constitutional chromosome 14 rearrangement was observed in a female with a psychodevelopmental disorder. Karyotype analysis using a variety of chromosome techniques, QFQ, GTG, CBG, Ag-NOR and DA-DAPI, showed a deletion of chromosome 14q32.1-qter region in association with a supernumerary marker chromosome. The marker, resembling a submetacentric, approximately half the size of a G group chromosome is C band and Ag-NOR negative. The heteromorphism of the satellites showed that the deleted chromosome 14 is paternal in origin. Chromosome painting using an Alu-PCR probe specific for the human chromosome 14 and fluorescent in situ hybridization (FISH) showed that the marker contains chromosome 14q32 sequences. It is likely that the marker was generated from the deleted chromosome 14 region through a complex rearrangement.     

Diagnosis of four chromosome abnormalities of unknown origin by chromosome microdissection and subsequent reverse and forward painting

A molecular cytogenetic method consisting of chromosome microdissection and subsequent reverse/forward chromosome painting is a powerful tool to identify chromosome abnormalities of unknown origin. We present 4 cases of chromosome structural abnormalities whose origins were ascertained by this method. In one MCA/MR patient with an add(5q)chromosome, fluorescence in situ hybridization (FISH), using probes generated from a microdissected additional segment of the add(5q) chromosome and then from a distal region of normal chromosome 5, confirmed that the patient had a tandem duplication for a 5q35-qter segment. Similarly, we ascertained that an additional segment of an add(3p) chromosome in another MCA/MR patient had been derived from a 7q32-qter segment. In a woman with a history of successive spontaneous abortions and with a minute marker chromosome, painting using microdissected probes from the whole marker chromosome revealed that it was i(15)(p10) or psu dic(15;15)(q11;q11). Likewise, a marker observed in a fetus was a ring chromosome derived from the paracentromeric region of chromosome 19. We emphasize the value of the microdissection-based chromosome painting method in the identification of unknown chromosomes, especially for marker chromosomes. The method may contribute to a collection of data among patients with similar or identical chromosome abnormalities, which may lead to a better clinical syndrome delineation. © 1996 Wiley-Liss, Inc.     

Similar mechanisms formed ring markers containing chromosome 12 pericentromeric region in two patients with therapy-related acute myeloid leukemia

Two cases of therapy-related acute myeloid leukemia showed complex karyotypes, including a small ring and a larger D-chromosome. Multicolor fluorescence in situ hybridization and bacterial artificial chromosome and fosmid clones showed that both ring chromosomes were composed entirely of material excised from chromosome 12. The deleted segment of 12 was found fused to the short arm of a D-group chromosome. We hypothesized that similar mechanisms were involved in both rearrangements. A fusion at the short arms of chromosome 12 and a D-group chromosome was accompanied by excision and ligation of the chromosome 12 pericentromeric region to form a small ring chromosome.     

dic(9; 20): A new recurrent chromosome abnormality in adult acute lymphoblastic leukemia

Loss of chromosome 20 and rearrangement of the short arm of chromosome 9 were identified by banding analysis of three adult patients with acute lymphoblastic leukemia (ALL). The G-banding pattern suggested and identical deletion of 9p, but, also, an unbalanced translocation with chromosome 20 was taken into consideration. Dual-color chromosome painting with probes for chromosomes 9 and 20 revealed the presence of material from chromosome 20 at the short arm of the abnormal chromosome 9 in all three cases. Centromeric alpha-satellite DNA of both chromosome 9 and chromosome 20 was demonstrated by fluorescence in situ hybridization and indicated the presence of a dicentric chromosome. The hybridization of a YAC clone of the short arm of chromosome 20 proved that the dicentric chromosome contained the short arm of chromosome 20, which had been suspected from the G-banding pattern. Thus, the rearrangement was interpreted as dic(9; 20)(pl I;qi I . ? I). Because this was the sole chromosome abnormality in two patients, dic(9; 20) may be a primary chromosome aberration in ALL. In one case, a 9q⁺ chromosome derived from a Philadelphia (Ph) translocation was involved in the formation of the dicentric chromosome. Immunophenotyping revealed CD 1o⁺ B-cell precursor ALL in all three cases. Whereas the two patients in whom dic(9; 20) was the sole cytogenetically detectable change are in continuous complete remission for 10 and 45 months, respectively, the Ph⁺ patient relapsed with leukemia and died 8 months after diagnosis. © 1995 Wiley-Liss, Inc.     

Numerical aberrations of chromosome 9 in bladder cancer. A possible prognostic marker for early tumor recurrence

Bilharzial bladder cancer is one of the most common types of malignancy in both men and women in several developing countries including Egypt. It has several unique clinical, epidemiological, and histological characteristics, suggesting that it is an entity distinct from bladder cancer seen in Western countries. Genetic alterations in bilharzial-related bladder cancer have been studied infrequently, especially in the advanced stages of disease, that is, T3 and T4 classifications. The objective of this study was to extend establishing the baseline cytogenetic profile of this type of malignancy to early T1 and T2 classifications. For this purpose, fluorescence in situ hybridization was applied to interphase nuclei of frozen-stored samples with biotinylated repetitive DNA probes specific for all chromosomes to detect numerical chromosome changes in 35 patients presenting with relatively early-stage pT1 and pT2 disease. Eleven cases had squamous cell carcinoma (SCC) and 24 had transitional cell carcinoma. Six of 24 transitional cell carcinomas had diploid chromosome counts with all the probes. Numerical chromosome aberrations were detected in 18 cases (75%). In 12 cases, a loss of chromosome 9 was observed. In three cases, an additional loss of chromosome 17 was detected. One case demonstrated a loss of chromosome 10, whereas another two cases showed a gain of chromosome 7, next to a loss of chromosome 9. Loss of chromosome Y was observed in nine of the 27 male cases studied (33.3%), in which only one case showed an abnormality whereas four cases were detected next to loss of chromosome 9, and one case showed gain of chromosome 7. Five cases showed loss of chromosome 19 whereas gain of chromosome 4 was detected in two cases. Two of 11 samples of SCC had normal diploid chromosome counts with all the probes used. In four of 11 cases (36.4%) underrepresentation of chromosome 9, compared with the other chromosomes, was detected. An additional loss of chromosome 17 and gain of chromosome 7, next to loss of chromosome 9, was detected in three cases. One case showed loss of chromosome 17 as the only numerical aberration. Loss of the Y chromosome was detected in three cases of which one case had gain of chromosome 7 and one case had loss of chromosome 19. No correlation was found between any of the clinicopathologic parameters examined in this study and the presence or absence of any numerical chromosomal aberrations except for the significant association between schistosomal history and loss of Y chromosome (P=0.007).     

1例13号环状染色体合并6号染色体末端重排核型的确定及遗传咨询

目的 确定1例13号环状染色体合并6号染色体末端重排核型，并为其生育提供指导。方法　1例有生育畸胎史的病例，染色体检测发现携带环状染色体，6号染色体短臂增加，选用6号和13号染色体特异性涂染探针进行荧光原位杂交分析。结果　确定其核型为环状13号染色体合并13号染色体长臂远端部分与6号染色体短臂的末端重排。结论 这是一例罕见的可能起源于三断裂的结构重排。根据减数分裂形成配子的规律，她仍有生育正常孩子的可能性，但必须进行产前诊断确保正常小孩的出生。     

The ring nature of a tiny supernumerary chromosome fragment

We report a 5½-year-old girl with a tiny supernumerary chromosome fragment found in mosaic. The ring nature of the tiny fragment was demonstrated by the detection of the characteristic products of a ring chromosome. The clinical consequence of a ring chromosome and the impact of finding a supernumerary chromosome fragment, especially in the practice of prenatal chromosome diagnosis, are discussed.     

Identification of supernumerary ring chromosome 1 mosaicism using fluorescence in situ hybridization

We report on a 15-year-old black boy with severe mental retardation, multiple congenital anomalies, and a supernumerary ring chromosome mosaicism. Fluorescence in situ hybridization with a chromosome 1 painting probe (pBS1) identified the ring as derived from chromosome 1. The karyotype was 46,XY/47,XY,+r(1)(p13q23). A review showed 8 reports of ring chromosome 1. In 5 cases, the patients had a non-supernumerary ring chromosome 1 resulting in partial monosomies of the short and/or long arm of chromosome 1. In 3 cases, the presence of a supernumerary ring resulted in partial trisomy of different segments of chromosome 1. In one of these cases the supernumerary ring was composed primarily of the centromere and the heterochromatic region of chromosome 1, resulting in normal phenotype. Our patient represents the third report of a supernumerary ring chromosome 1 resulting in abnormal phenotype. © 1995 Wiley-Liss, Inc.     

A non-sex chromosome marker in a patient with an atypical Ullrich-Turner phenotype and mosaicism of 46,X,mar/46,XX

The absence of a sex chromosome in conjunction with the presence of a marker chromosome generally implicates a sex chromosome origin for such marker chromosomes. These types of findings are frequently associated with Ullrich-Turner syndrome. We report a patient that presented with an atypical Ullrich-Turner phenotype and a cytogenetic mosaicism of 46,X,mar/46,XX. The marker chromosome was derived from chromosome 20, not from the X or Y chromosome. The patient's clinical features are described and discussed relative to the cytogenetic findings. This case further demonstrates the necessity of marker chromosome identification for accurate phenotype-karyotype correlation.     

A non-isotopic in situ hybridisation study of the chromosomal origin of 15 supernumerary marker chromosomes in man.

Fifteen patients presenting with mosaic or non-mosaic karyotypes containing a distamycin-DAPI negative de novo or familial supernumerary marker chromosome were studied with non-isotopic in situ hybridisation using a library of alphoid centromere specific and satellite II/III probes. The in situ hybridisation studies showed that seven markers were derived from satellited autosomes (three chromosome 13/21, two chromosome 14, two chromosome 22), six from non-satellited autosomes (two chromosome 4, one chromosome 12, one chromosome 16, two chromosome 19), and one from the Y chromosome. One non-mosaic marker was negative for all the alphoid and satellite II/III probes used.     

The origin of human chromosome 1 and its homologs in placental mammals

Developing ordered gene maps from multiple mammalian species coupled with chromosome-painting data provide a powerful resource for resolving the evolutionary history of chromosomes and whole genomes. In this work, we recapitulate the evolutionary history of human chromosome 1 and its homologs in placental mammals, putatively the largest physical unit in the ancestral placental genome. Precise definition of translocation exchange breakpoints in human, carnivore, cetartiodactyl, and rodent-ordered gene maps demonstrate that chromosome breakpoints, previously considered as equivalent, actually represent distinct chromosome positions and exchange events. Multidirectional chromosome painting, using probes from homologs to chromosome 1 in seven mammal species from six orders of placental mammals, confirm the gene-mapping results and indicate that the multiple human chromosome 1 homologs in these species are derived from independent fissions of a single ancestral chromosome. Chromosome painting using human chromosome 1 probes identifies a single human chromosome 1 homolog in phylogenetically distant taxa, the two-toed sloth, cetaceans, and higher primates. The diverse phylogenetic occurrence of a single Hsa1 synteny among the major clades of placental mammals suggests that human chromosome 1 represents an intact ancestral chromosome, which was variously fissioned in the majority of placental species. We find that the number of human chromosome 1 fissions in a specific lineage reflects its general rate of genomic evolution. Further, historic chromosome exchange appears to have been disproportionately clustered in two breakpoint hotspots on the long arm.     

Chromosome abnormalities in malignant melanoma: clinical significance of nonrandom chromosome abnormalities in 206 cases

We report the cytogenetic abnormalities from a series of 206 primary malignant melanoma specimens referred to a single institution. A total of 169 out of 206 unique cases had chromosome breakpoints. A previously described statistical method was used to detect nonrandom distribution of chromosome breakpoints at the level of chromosome regions. Nonrandom occurrence of chromosome breakpoints (indicating that the observed number of breaks significantly exceeded the expected number of breaks) was detected in 28 regions, suggesting a hierarchy of genetic abnormalities in melanoma. Clinical variables and tumor characteristics were analyzed for associations with the presence of any nonrandom chromosome breakpoints; with individual, nonrandomly involved chromosome regions; and with paired, nonrandomly involved chromosome regions. No nonrandomly involved chromosome regions or pairs of regions appeared to significantly affect survival. These results identify recurring, nonrandom chromosome abnormalities in malignant melanoma. These results suggest that recurring, nonrandom chromosome alterations play a key role in the etiology and/or progression of malignant melanoma and identify targets within the genome for molecular genetic studies.     

Familial transmission of a deletion of chromosome 21 derived from a translocation between chromosome 21 and an inverted chromosome 22

Chromosome analysis of a newborn boy with Down syndrome resulted in the identification of a family with an unusual derivative chromosome 22. The child has 46 chromosomes, including two chromosomes 21, one normal chromosome 22, and a derivative chromosome 22. Giemsa banding and fluorescent in situ hybridization (FISH) studies show that the derivative chromosome is chromosome 22 with evidence of both paracentric and pericentric inversions, joined to the long arm of chromosome 21 from 21q21.2 to qter. The rearrangement results in partial trisomy 21 extending from 21q21.2 to 21q terminus in the patient. The child's mother, brother, maternal aunt, and maternal grandmother are all carriers of the derivative chromosome. All have 45 chromosomes, with one normal chromosome 21, one normal chromosome 22, and the derivative chromosome 22. The rearrangement results in the absence of the short arm, the centromere, and the proximal long arm of chromosome 21 (del 21pter21q21.2) in carriers. Carriers of the derivative chromosome in this family have normal physical appearance, mild learning disabilities and poor social adjustment. Am. J. Med. Genet. 70:399–403, 1997. © 1997 Wiley-Liss, Inc.     

The sex-determining region of theMegaselia scalaris (Diptera) Y chromosome

InMegaselia scalaris (Loew) the presence or absence of a male-determining factor, M, is responsible for sex determination. In two wild-type strains, M is located on the homomorphic chromosome pair 2. In the laboratory line Except42 a new Y chromosome was created by recombination between the original Y and the original X chromosome. The Except42 Y chromosome has conserved the sex-determining function and four molecular markers of the original Y chromosome, while 13 original Y markers have been lost. The new Y chromosome, therefore, consists of roughly one-quarter of the original Y chromosome and three-quarters of the original X chromosome. To define the sex-determining region, cosmid clones, one from the original X and one from the original Y chromosome region of the Except42 Y chromosome, were isolated and used as probes for chromosomalin situ suppression (CISS) hybridization. The CISS hybridization signals map the conserved Y segment, including the male-determining factor, to the distal segment of the short arm of the Y chromosome.     

A constitutional complex chromosome rearrangement involving meiotic arrest in an azoospermic male: case report

Complex chromosome rearrangements are rare aberrations that frequently lead to reproductive failure and that may hinder assisted reproduction. A 25-year-old azoospermic male was studied cytogenetically with synaptonemal complex analysis of spermatocytes from a testicular biopsy and fluorescence in situ hybridization (FISH) of lymphocytes. The spermatocytes showed a pentavalent plus a univalent chromosome. Cell death occurred mainly at advanced pachytene stages. The sex chromosomes were involved in the multiple, as shown by their typical axial excrescences. Two autosomal pairs, including an acrocentric chromosome (15), were also involved in the multiple. FISH allowed the definite identification of all the involved chromosomes. An inverted chromosome 12 is translocated with most of one long arm of chromosome 15, while the centromeric piece of this chromosome 15 is translocated with Yqh, forming a small marker chromosome t(15;Y). The euchromatic part of the Y chromosome is joined to the remaining piece of chromosome 12, forming a neo-Y chromosome. The patient shows azoospermia and a normal phenotype. The disruption of spermatogenesis is hypothetically due to the extent of asynaptic segments and to sex-body association during pachytene. This CCR occurred 'de novo' during paternal spermatogenesis. Meiotic analysis and FISH are valuable diagnostic tools in these cases.     

The human Y chromosome.

Despite its central role in sex determination, genetic analysis of the Y chromosome has been slow. This poor progress has been due to the paucity of available genetic markers. Whereas the X chromosome is known to include at least 100 functional genetic loci, only three or four loci have been ascribed to the Y chromosome and even the existence of several of these loci is controversial. Other factors limiting genetic analysis are the small size of the Y chromosome, which makes cytogenetic definition difficult, and the absence of extensive recombination. Based on cytogenetic observation and speculation, a working model of the Y chromosome has been proposed. In this classical model the Y chromosome is defined into subregions; an X-Y homologous meiotic pairing region encompassing most of the Y chromosome short arm and, perhaps, including a pseudoautosomal region of sex chromosome exchange; a pericentric region containing the sex determining gene or genes; and a long arm heterochromatic genetically inert region. The classical model has been supported by studies on the MIC2 loci, which encode a cell surface antigen defined by the monoclonal antibody 12E7. The X linked locus MIC2X, which escapes X inactivation, maps to the tip of the X chromosome short arm and the homologous locus MIC2Y maps to the Y chromosome short arm; in both cases, these loci are within the proposed meiotic pairing region. MIC2Y is the first biochemically defined, expressed locus to be found on the human Y chromosome. The proposed simplicity of the classical model has been challenged by recent molecular analysis of the Y chromosome. Using cloned probes, several groups have shown that a major part of the Y chromosome short arm is unlikely to be homologous to the X chromosome short arm. A substantial block of sequences of the short arm are homologous to sequences of the X chromosome long arm but well outside the pairing region. In addition, the short arm contains sequences shared with the Y chromosome long arm and sequences shared with autosomes. About two-thirds of XX males contain detectable Y derived sequences. As the amount of Y sequences present varies in different XX males, DNA from these subjects can be used to construct a map of the region around the sex determining gene. Assuming that XX males are usually caused by simple translocation, the sex determining genes cannot be located in the pericentric region. Although conventional genetic analysis of the Y chromosome is difficult, this chromosome is particularly suited to molecular analysis. Paradoxically, the Y chromosome may soon become the best defined human chromosome at the molecular level and may become the model for other chromosomes.     

Origins and inheritance of chromosome-length polymorphisms in the barley covered smut fungus, Ustilago hordei

Numerous chromomsome-length polymorphisms (CLPs) associated with chromosome IV were detected in an inbred line of race 8 of Ustilago hordei (teliospore line 1279). Polymorphisms for chromosome IV were observed in the 1600–1900-kb range in approximately 8% of the haploid sporidia originating from this teliospore collection. A monosporidial strain, 1279Ca2, exhibited a new 1620-kb chromosome band and a concurrent loss of the 1950-kb chromosome IV. A ribosomal DNA probe from Armillaria mellea specifically hybridized to both the variant 1620-kb chromosome and to the 1950-kb rDNA chromosome IV in parental strains. Following digestion of chromosome IV with HinfI, the telomere fragments of the 1620-kb chromosome were similar to those of the 1950-kb chromosome IV, indicating that the 1620-kb chromosome arose following a deletion of approximately 330 kb from chromosome IV. The Hinf1 digest of chromosome IV, when probed with the rDNA probe, revealed that much of the rDNA of chromosome IV was lost in the 1279Ca2 line. rDNA sequences were coincidentally recorded in chromosomes I and II in the sister sporidial line, 1279Ca4. When the 1279Ca2 line was mated to other members within the same tetrad and inoculated onto susceptible barley, karyotypes of tetrads and random sporidia originating from the F₁ progeny possessed variant chromosomes ranging in size from 1536 to 2110 kb. Among sporidia in 5 of the 12 ordered tetrads sampled, a 1:1 ratio of the 1950-kb parental chromosome IV to the variant chromosome was observed. Within these tetrads, the two polymorphic chromosomes were identical in size and larger than that of the original variant 1620-kb chromosome suggesting that a chromosome expansion, averaging 150 kb, had occurred. In 5 of the 12 tetrads, a 1:1:1:1 ratio representing the two original parents and two recombinant chromosomes was observed, suggesting that normal or unequal recombination had occurred during meiosis. In 2 of the 12 F₁ progeny tetrads, the 1950-kb chromosome IVs were apparently eliminated. In karyotypes of these sporidial lines, we observed rDNA sequences in chromosomes I and III that were translocated from chromosome IV. Among 78 random sporidia in the F₁ generation, duplication of the variant chromosome IV was observed in three strains. These results suggest that polymorphisms in the rDNA chromosome IV, which consist of chromosome expansion, translocation, and chromosome elimination or duplication, are common in the 1279 strain of U. hordei and its progeny, and that this variability appears to be associated with the tandem-repeat nature of the rDNA sequences. Received: 12 May / 18 November 1997     

一个涉及1号和7号染色体插入易位家系的鉴定

目的 确定一个有反复流产史且常规G显带发现有7q末端缺失病例的核型,探讨染色体末端区域插入易位的形成机理。方法 应用显微切割制备的7号特异性全染色体探针和7q亚端粒（7q36→qter)探针,与病例的中期分裂相进行荧光原位杂交（fluorescence in situ hybridization,FISH)。结果 发现了该病例为常规G显带难以妈现的1号和7号染色体之间的插入易位,7q36→qter区域没有插入到1号染色体中,其异常核型来源于其母亲。结论 为染色体末端区域的插入易位仍然为一个三断裂重排。细胞遗传学上见到的末端缺失为中间缺失提供了实验证据,FISH与显微切割技术相结合。是检出染色体微小结构异常的一个强有力的工具。     

Construction of microcell hybrid panel containing differentNeo gene insertions in mouse chromosome 17 used for chromosome-mediated gene transfer

A panel of four microcell hybrids representing different sites of insertion of the exogeneous neogene into mouse chromosome 17 has been constructed. These constructions were based on a cotransfer of mouse chromosome 17 and neomycin resistance generated in a stepwise procedure involving (1) random insertion of the neogene into a primary cell hybrid containing mouse chromosome 17 in a hamster cell background, (2) microcell-mediated chromosome transfer (MMCT) to segregate mouse and hamster chromosomes, and (3) identification of the mouse chromosome containing cells using a novel cell dotting procedure for mass screening at the cell colony level by molecular hybridization. Using this panel of four microcell hybrids for chromosome mediated gene transfer (CMGT), we obtained one transformant containing a chromosome fragment derived from the t-complex region located on mouse chromosome 17. It is concluded that the specific chromosome based procedure used here to generate CMGT transfectants may provide a general means to produce large numbers of transfectants containing megabase fragments covering, in principle, all regions of a given chromosome.