RESUMEN
Translocations involving the immunoglobulin loci are recurring events of B cell oncogenesis. The majority of translocations involve the immunoglobulin heavy chain (IGH) locus, while a minor part involves the immunoglobulin light chain loci consisting of the kappa light chain (IGK) located at 2p11.2 and the lambda light chain (IGL) located at 22q11.2. We characterised BAC clones, spanning the IGK and IGL loci, for detection of illegitimate rearrangements by fluorescence in situ hybridisation (FISH). Within the IGL region we have identified six end sequenced probes (22M5, 1152K19, 2036J16, 3188M21, 3115E23 and 274M7) covering the variable (IGLV) cluster and two probes (165G5 and 31L9) covering the constant (IGLC) cluster. Within the IGK region four probes (969D7, 316G9, 122B6 and 2575M21) have been identified covering the variable (IGKV) cluster, and one probe (1021F11) covering the IGK constant (IGKC) cluster. A series of 24 cell lines of different origin have been analysed for the presence of translocations involving the immunoglobulin light chain loci by dual-colour FISH where the split of the variable cluster and the constant cluster indicated a translocation. Probes established in this study can be used for universal screening of illegitimate rearrangements within the immunoglobulin light chain loci in B cell malignancies.
Asunto(s)
Sondas de ADN , Reordenamiento Génico , Cadenas Ligeras de Inmunoglobulina/genética , Leucemia de Células B/genética , Linfoma de Células B/genética , Humanos , Hibridación Fluorescente in Situ , Cariotipificación , Leucemia de Células B/patología , Linfoma de Células B/patología , Translocación Genética , Células Tumorales CultivadasRESUMEN
We report an eleven years old boy and his fourteen years old brother who both have trisomy 9p syndrome. Their cytogenetic analysis using GTL-banding showed 46,XY,der(22)add(22)(p11) karyotype. Cytogenetic analysis of their mother and sister revealed a karyogram designated as 46,XX,t(9;22) (9pter-->9p12::22p11-->22qter). With the help of FISH technique, the derivative chromosome in the proband was further confirmed to be a translocation chromosome 22 carrying the aforementioned segments from chromosome 9 which originated from a segregation event of a mother's balanced translocation. Regarding clinical aspects of our cases, both showed similar findings of 9p trisomy syndrome but low frontal hairline, circular placement of the hair around the face and scarce, inverted eyebrows, findings not previously mentioned in the literature. We conclude that these new clinical findings could be used in the clinical diagnosis of the 9p trisomy syndrome along with the other well-documented symptoms.
Asunto(s)
Anomalías Múltiples/genética , Cromosomas Humanos Par 9 , Hermanos , Trisomía , Adolescente , Niño , Humanos , Cariotipificación , Masculino , Linaje , Síndrome , Translocación GenéticaRESUMEN
Translocation involving the immunoglobulin heavy chain (IGH) locus is a recurring event in B-cell oncogenesis. The aim of this study was to characterize clones from bacterial artificial chromosome (BAC) libraries and/or bacteriophage P1 artificial chromosome libraries spanning the IGH locus for detection of illegitimate rearrangement within the region by fluorescence in situ hybridization (FISH). In silico analysis of the IGH variable (IGHV) DNA sequence (NT_001716.v1) was performed to identify BAC probes located within the IGHV cluster. Clones of the constant (IGHC) cluster were found in the literature or at http://www.biologia.uniba.it/rmc/. Validation, orientation, and overlap of these probes were confirmed using interphase-, metaphase-, and fiber-FISH. We have identified seven BAC end-sequenced probes (3087C18, 47P23, 76N15, 12F16, 101G24, 112H5, and 151B17) covering 612 kb of the distal IGHV cluster, which, together with probes covering the IGHC cluster (11771 and 998D24), could be used in interphase nuclei and metaphase chromosome analysis. A visual split of the IGHV and IGHC clusters indicating a translocation was analyzed by dual-color FISH in a series of 21 cell lines of different origins. Translocations were found, as expected, in eight of eight myelomas, four of four lymphomas, none of five leukemias, and none of four Epstein-Barr virus-transformed B-lymphoblastoid cell lines. To summarize, we have established a set of IGHV and IGHC probes that can be used for universal screening of illegitimate rearrangement within the IGH locus in B-cell malignancies. These probes allow for routine FISH analysis to detect this early central oncogenic event.
Asunto(s)
Sondas de ADN/genética , Reordenamiento Génico de Cadena Pesada de Linfocito B , Cadenas Pesadas de Inmunoglobulina/genética , Linfoma de Células B/genética , Translocación Genética/genética , Bandeo Cromosómico , Cromosomas Artificiales Bacterianos/genética , Cromosomas Humanos Par 15/genética , Cromosomas Humanos Par 16/genética , Marcadores Genéticos/genética , Humanos , Hibridación Fluorescente in Situ/métodos , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico/métodos , Células Tumorales CultivadasRESUMEN
A 39 year old male with primary infertility was diagnosed as having Klinefelter syndrome by conventional cytogenetic analysis, which also showed an abnormal chromosome 12. Fluorescence in situ hybridisation (FISH) analysis of the aberrant chromosome using a 12 specific centromeric probe showed a break in the alphoid repeats followed by an inversion within the short arm, resulting in a pseudodicentric chromosome. Further FISH analyses using telomeric and subtelomeric probes showed that the other breakpoint was in the subtelomeric region of the short arm. The karyotype is designated 47,XXY,inv(12)(p10p13.3). To our knowledge this is the first report of a case of "centric inversion".
Asunto(s)
Aberraciones Cromosómicas , Inversión Cromosómica , Cromosomas Humanos Par 12 , Síndrome de Klinefelter/genética , Adulto , Células Cultivadas , Humanos , Hibridación Fluorescente in Situ , Cariotipificación , Masculino , Cromosoma XRESUMEN
We describe two female patients mosaic for a cell line with an extra marker X chromosome in addition to a normal 46,XX cell line. To our knowledge, these cases are the first reports of females who had a cell line with a supernumerary marker X chromosome in addition to a normal cell line. They also had strikingly similar manifestations, including small hands and feet, minor facial anomalies, obesity, and mental retardation. The DNA content of the mar(X) chromosomes was investigated by fluorescent in situ hybridization using pericentromeric probes. The XIST gene, which is necessary for initiation of X-inactivation, was deleted from both marker chromosomes, suggesting that these chromosomes were not subject to inactivation. The short arm breakpoints of the mar(X)s were between the DNA markers DXS423E on Xp11.21 and UBE1 on Xp11.23. In Patient 1, mar(X) contained the androgen receptor gene and the DNA marker DXS1, both mapping to Xq11.2, whereas in Patient 2 the chromosome breakpoint was proximal to these markers. We suggest that the similar phenotypes of these patients may be due to the overexpression of genes in the common pericentromeric region of the X chromosome.
Asunto(s)
Anomalías Múltiples/genética , Aberraciones Cromosómicas , Cromosoma X/genética , Adolescente , Adulto , Anomalías Craneofaciales/genética , Compensación de Dosificación (Genética) , Femenino , Deformidades Congénitas del Pie/genética , Marcadores Genéticos , Deformidades Congénitas de la Mano/genética , Humanos , Hibridación Fluorescente in Situ , Discapacidad Intelectual/genética , Mosaicismo , Obesidad/genética , FenotipoRESUMEN
Cytogenetic analysis of a girl with moderate mental retardation and dysmorphic features revealed a 46,XX/47,XX,+mar karyotype. Fluorescence in situ hybridization using chromosome specific alpha satellite probes showed that the supernumerary marker originated from the X chromosome. To our knowledge, this is the first reported case of a female patient mosaic for a supernumerary small marker chromosome derived from X, and hence mosaic for trisomy of the pericentric region of the X chromosome.
Asunto(s)
Aberraciones Cromosómicas , Trastornos de los Cromosomas , Marcadores Genéticos , Cromosoma X , Niño , Sondas de ADN , ADN Satélite , Cara/anomalías , Femenino , Humanos , Hibridación Fluorescente in Situ , Discapacidad Intelectual/genética , Cariotipificación , Trastornos del Habla/genéticaRESUMEN
A 46,X,t(X;X) (qter-->p22;;p22-->qter) karyotype was found in the chromosome analysis of a 22 years old female patient with secondary amenorrhea. Further analysis with fluorescence in situ hybridization indicated that the marker chromosome had one active and one inactive centromere originating from the X chromosome. RBG-banding showed that the derivative X chromosome was preferentially inactivated in cultured lymphocytes.
Asunto(s)
Amenorrea/genética , Translocación Genética , Cromosoma X , Adulto , Mapeo Cromosómico , Femenino , Humanos , Hibridación Fluorescente in Situ , Cariotipificación , Linfocitos/citología , Linfocitos/patologíaRESUMEN
Low levels of pregnancy-associated plasma protein A (PAPPA) during the first trimester has been suggested as a biochemical indicator of pregnancies with aneuploid fetuses. Furthermore, the complete absence of PAPPA in pregnancies associated with Cornelia de Lange syndrome (CL) has suggested a causal connection between PAPPA and the development of CL. We have assigned the locus for PAPPA to chromosome region 9q33.1 on mitotic and meiotic chromosomes by fluorescence in situ hybridization, using a 3.7-kb partial PAPPA cDNA probe.