Familial deletion 11q14.3-q22.1 without apparent phenotypic consequences: a haplosufficient 8.5 Mb region.

We present the prenatal diagnosis of a chromosome 11q14.3-q22.1 deletion identified in three generations without apparent phenotypic consequences. A 25-year-old G2, P1 woman underwent amniocentesis at 15 weeks' gestation because of a positive result for Down syndrome maternal serum-screening test (1/70). The fetal karyotype revealed an interstitial deletion of the long arm of chromosome 11 confirmed by CGH and FISH: 46,XX,del(11)(q14.3q22.1). The mother and grandfather of the fetus presented the same interstitial deletion with a little if any phenotype effect. The pregnancy was carried to term and resulted in the birth of a normal girl. To our knowledge, only one case of a chromosome 11q14.3-q21 deletion without phenotypic anomalies has been reported. Our study allows the initially described haplosufficient region to be extended from 3.6 Mb to at least 8.5 Mb. This large deletion was compatible with fertility and apparently normal phenotype. Identification of such chromosomal regions is important for prenatal diagnosis and genetic counseling.

Larsen-like phenotype associated with partial trisomy 3p and monosomy 5p.

BACKGROUND: We report on a fetus with radiographic features of Larsen Syndrome (LS) and unbalanced 3;5 translocation. Recently LS was shown to be caused by mutations in FLNB gene which maps on 3p14.3. METHODS: Comparative genomic hybridization (CGH) was performed to search for genomic imbalances. Fluorescence in situ analysis (FISH) was done with BAC clone RP11-754F19 probe from the FLNB gene region (3p14.3). RESULTS: CGH showed a large loss of the chromosome 5 short arm and a gain of half of the short arm of chromosome 3 resulting from a derivative chromosome 5. FISH analysis with FLNB probe demonstrated that it was not triplicated. Thus, we excluded the role of a gene dosage effect of FLNB in abnormal craniofacial development in this fetus. CONCLUSIONS: To our knowledge, this is the first report of Larsen-like phenotype associated with unbalanced translocation resulting in partial trisomy 3p and monosomy 5p.

De novo balanced complex chromosome rearrangement (CCR) involving chromosome 8, 11 and 16 in a boy with mild developmental delay and psychotic disorder.

Congenital Complex Chromosome rearrangements (CCRs) compatible with life are rare in humans. We report a de novo CCR involving chromosomes 8, 11 and 16 with 4 breakpoints in a patient with mild dysmorphic features, acquisition delay and psychotic disorder. Conventional cytogenetic analysis revealed an apparently balanced 8;16 translocation. Further FISH analysis with WCP 8 and WCP 16 probes revealed the presence of a third chromosome involved in the translocation. The multicolour karyotype confirmed the complexity of the rearrangement and showed that the derivative chromosome 8 was composed of 3 distinct segments derived from chromosomes 8, 16 and 11. The breakpoints of this complex rearrangement were located at 8q21, 11q14, 11q23 and 16q12. Comparative genomic hybridization (CGH) and array-CGH were performed to investigate the possibility of any genomic imbalance as a result of the complex rearrangement. No imbalance was detected by these two techniques. Our study showed: i) the necessity to confirm reciprocal translocations with FISH using painting probes, particularly when the karyotype resolution is weak; ii) the usefulness of multicolour karyotype for the characterization of structural chromosomal rearrangements, particularly when they are complex; iii) the usefulness of CGH and array-CGH in cases of abnormal phenotype and apparently balanced rearrangement in order to explore the breakpoints and to detect additional imbalances.

Allogeneic stem cell transplantation improves the outcome of adults with t(1;19)/E2A-PBX1 and t(4;11)/MLL-AF4 positive B-cell acute lymphoblastic leukemia: results of the prospective multicenter LALA-94 study.

Adult patients with acute lymphoblastic leukemia (ALL) and t(1;19)/E2A-PBX1 or t(4;11)/MLL-AF4 have a poor outcome. We have evaluated the impact of an intensified post-remission therapy using a high-dose chemotherapy course followed by allogeneic or autologous SCT on the outcome of 58 patients with t(1;19)/E2A-PBX1 (E2A group, n=24) or t(4;11)/MLL-AF4 (MLL group, n=34) treated in the LALA-94 multicenter prospective study. Patients in the MLL group had higher WBC counts and more frequent DIC. CR rates achieved by MLL and E2A groups were similar to other B-cell ALL (87, 82 and 86% respectively). While in CR, patients with a donor were assigned to alloSCT (n=22), the remaining patients with were randomized between autoSCT (n=15) or chemotherapy (n=8). Five-year overall survival was 31 and 45% for E2A and MLL groups, respectively. In both groups, DFS was higher in the alloSCT arm as compared to autoSCT and chemotherapy arms. The results of this study show that chemotherapy intensification did not overcome the poor prognosis of adults with t(1;19)/E2A-PBX1. Allogeneic SCT should thus be offered in first CR to patients with t(1;19)/E2A-PBX1 or t(4;11)/MLL-AF4. New therapeutic approaches are needed for patients without donor.

An unusual familial chromosome 9 "variant" with variable phenotype: characterization by CGH analysis.

Heterochromatin confined to pericentromeric and secondary constriction regions plays a major role in morphological variation of chromosome 9, because of its size and affinity for pericentric inversion. We report on a 6-year-old boy with growth and language delay, minor facial anomalies and unusual chromosome 9 variant with an extra-band in the centromeric region on the conventional karyotype. Subsequent analysis by FISH and CGH identified this variant as a dicentric chromosome 9 with a duplication of the 9p12-q21 region. An identical chromosome 9 variant was found in the mild language retarded brother and in the phenotypically normal father and grandfather. The presumed mechanism accounting for the phenotypic discordance observed in this family and the usefulness of CGH in characterization of such variants are discussed. To our knowledge, this is the first investigation of an unusual chromosome 9 variant by CGH.

Structural and numerical aberrations of chromosome 22 in a case of follicular variant of papillary thyroid carcinoma revealed by conventional and molecular cytogenetics.

This study reports a case of papillary carcinoma with vesicular components showing multiclonal aberrations of chromosome 22 as revealed by RHG-banding cytogenetics and by fluorescence in situ hybridization (FISH; whole chromosome 22 and BCR-ABL-specific locus probes, multi-FISH). Four clones with chromosome 22 changes as the sole abnormality were seen. The main abnormal clone lacked the whole chromosome 22. A del(22)(q11) was observed in a second group of cells. The third clone had an idic(22). Finally, FISH revealed a fourth abnormal cell population with a der(17)t(?17;22). Some of these chromosome 22 alterations have been described in other solid tumors such as meningiomas and neurinomas, suggesting a common genetic pathway of tumor progression occurring in a multistep process. Chromosome 22 changes do not seem to be involved in pure papillary thyroid tumors and therefore could be related to the maintenance of a follicular-type histological pattern.

Molecular detection of a late-appearing BCR-ABL gene in a child with T-cell acute lymphoblastic leukemia.

Approximately 2-5% of children with newly diagnosed acute lymphoblastic leukemia (ALL) have a Philadelphia (Ph) chromosome detectable on cytogenetic analysis, which is associated with a poor prognosis. In rare ALL cases the Ph chromosome may appear in leukemic cells during the course of the disease. We report here the case of a 5.5-year-old male patient with T-ALL who was found to have the b2a2 BCR-ABL mRNA transcript by reverse transcriptase-polymerase chain reaction (RT-PCR) at first marrow relapse. At the time of initial diagnosis, no BCR-ABL transcripts had been detected by PCR in the patient's blood and marrow samples. Further studies were performed using a competitive PCR titration assay and the fluorescence in situ hybridization (FISH) method to monitor the leukemic clone. Progression of the disease was associated with a higher BCR-ABL transcript level and an increasing proportion of BCR-ABL-positive cells. Metaphase FISH analysis identified the presence of the BCR-ABL fusion gene on a normal chromosome 22. This study shows that a late-appearing Ph translocation in ALL may be cytogenetically invisible. Quantitative RT-PCR and FISH techniques are appropriate and efficient methods for detecting these rare ALL variants expressing the BCR-ABL fusion gene and for estimating the level of residual disease following treatment.

Interphase cytogenetics and competitive RT-PCR for residual disease monitoring in patients with chronic myeloid leukaemia during interferon-alpha therapy.

There is a need for fast and sensitive methods to evaluate the response of patients with chronic myeloid leukaemia (CML) to interferon-alpha (IFN-alpha) therapy to complement cytogenetic analysis of Philadelphia (Ph) chromosome-positive metaphases. We have used interphase FISH (fluorescence in situ hybridization) and competitive RT-PCR (reverse transcriptase-polymerase chain reaction) techniques for detection of BCR-ABL-positive cells to measure suppression of leukaemic clone in a series of 51 follow-up samples from 24 CML patients undergoing IFN-alpha treatment. Interphase FISH analysis of the malignant clone in bone marrow using BCR and ABL probes was found to be highly correlated to conventional G-banding metaphase examination (r = 0.98). RT-PCR quantification of BCR-ABL mRNA transcripts in blood also showed a high degree of concordance with the proportion of Ph-positive metaphases (r = 0.93). In addition, the degree of cytogenetic response did not influence the equivalence between karyotype analysis and molecular methods. We concluded that interphase FISH and competitive RT-PCR provide reliable information on residual tumour burden and response to IFN-alpha in CML patients. These molecular methods may significantly improve the efficiency of residual disease monitoring during IFN-alpha therapy of CML.

Molecular monitoring of tumor cell contamination in leukapheresis products from stage IV neuroblastoma patients before and after positive CD34 selection.

BACKGROUND: Autologous peripheral blood stem cell (PBSCs) are frequently used to reconstitute hematopoiesis following administration of megatherapy in children with advanced stage IV neuroblastoma. Some centers prefer the use of autografts enriched for CD34+ progenitor cells because the positive selection procedure is believed to reduce indirectly tumor cell contamination. PROCEDURES: In this study, we monitored the efficiency of tumor cell purging following CD34 selection in PBSCs from seven patients with advanced neuroblastoma by using a highly sensitive reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, Amplification of tissues-specific mRNA transcript of tyrosine hydroxylase gene with nested primers enabled the detection of residual neuroblastoma cells with a sensitivity of one malignant-cell per 10(6) normals. RESULTS: Using this method, contaminating tumor cells were detected in seven of nine leukapheresis products of the patients. After positive immunoselection of CD34+ cells on Ceprate column, only one of nine enriched stem cell fraction still contained tumor cells detectable by RT-PCR. In six cases, PCR positive PBSCs became PCR negative after selection. CONCLUSIONS: We conclude that tumor cell contamination may be frequently detected in PBSC harvests of stage IV neuroblastoma patients by sensitive molecular analysis. The load of contaminating malignant cells might be reduced following CD34 selection.

Detection of heterozygous carriers of the ataxia-telangiectasia (ATM) gene by G2 phase chromosomal radiosensitivity of peripheral blood lymphocytes.

In ataxia-telangiectasia (A-T) patients, mutations in a single gene, ATM, result in an autosomal recessive syndrome that embraces a variety of clinical features and manifests extreme radiosensitivity and a strong pre-disposition to malignancy. Heterozygotes for the ATM gene have no clinical expression of A-T but may be cancer prone with a moderate increase in in vitro radiosensitivity. We performed a blind chromosomal analysis on G2-phase lymphocytes from 7 unrelated A-T patients, 13 obligate A-T heterozygotes (parents of the patients), and 14 normal controls following X-irradiation with 1 Gy in order to evaluate this cytogenetic method as a tool for detection of ATM carriers. Both A-T homozygotes and heterozygotes showed significantly increased levels of radiation-induced chromatid damage relative to that of normal controls. These results show that the G2-phase chromosomal radiosensitivity assay can be used for the detection of A-T heterozygotes. In combination with molecular genetic analyses, this test may be of value in studies of familial and sporadic cancers aimed at determination of the potential involvement of ATM mutations in tumor risk or development.

Characterization of double minute chromosomes' DNA content in a human high grade astrocytoma cell line by using comparative genomic hybridization and fluorescence in situ hybridization.

The presence of double minute chromosomes (dmin) in cancer cells is known to be correlated with gene amplifications. In human high grade astrocytomas or glioblastomas, about 50% of cytogenetically characterized cases display dmin. G5 is a cell line which has been established from a human glioblastoma containing multiple dmin. In order to identify the DNA content of these dmin, three techniques were successively used: conventional cytogenetic analysis, comparative genomic hybridization (CGH). and fluorescent in situ hybridization (FISH). The karyotype of G5 cells showed numerical chromosome changes (hypertriploidy), several marker chromosomes, and multiple dmin. CGH experiments detected two strong DNA amplification areas located in 9p21-22 and 9p24, as well as an underrepresentation of chromosomes 6, 10, 11, 13, 14, and 18q. By using FISH with a chromosome 9-specific painting probe to metaphase chromosomes of the G5 cell line, dmin were shown to contain DNA sequences originating from chromosome 9. This study demonstrates the usefulness of a combination of classical karyotyping, CGH, and FISH to identify the chromosomal origin of amplified DNA sequences in dmin.

Cytogenetic and molecular findings in patients with Turner's syndrome stigmata.

Cytogenetic and DNA analysis in 12 people with stigmata of Turner's syndrome was carried out. Cytogenetic analysis of these patients showed two subjects with 46,X, i(Xq) karyotypes, one with 45,X/46,X, i(Xq), one with 46,X,t(X;Y), and eight with 45,X/46,X,mar. Molecular analysis of DNA samples was performed in nine out of 12 patients with marker chromosomes. PCR analysis with oligoprimers specific for SRY, DYZ1, or DYZ3 loci identified Y chromosome material in five patients in the latter group. The X chromosome origin of the marker chromosome was proved by FISH technique with biotin labelled pericentromeric X chromosome specific probe in four other patients. These results show that patients with a number of Turner's syndrome stigmata usually do not have a typical XO karyotype but have some structural chromosomal aberrations involving the X or Y chromosomes. Combined application of cytogenetic, molecular cytogenetic (FISH), and PCR techniques significantly improves the precision of marker chromosome identification and thus might be of practical importance for the proper management and treatment of affected patients. Peculiarities of pathological manifestations of different karyotypes bearing structural abnormalities of the X or Y chromosomes in patients with Turner's syndrome stigmata, as well as feasible genetic mechanisms of sex determination and differentiation abnormalities in these subjects, are briefly discussed.

Hardware and software requirements for quantitative analysis of comparative genomic hybridization.

Recommendations are made for hardware and software capabilities that will permit a level of performance of comparative genomic hybridization (CGH) analysis on metaphase chromosomes that is comparable to the best current practice. Guidelines for interpreting the results of CGH analysis in terms of chromosomal gains or losses are also presented.

X;Y translocation in a girl with short stature and some features of Turner's syndrome: cytogenetic and molecular studies.

A 13 year old girl referred for chromosome analysis because of disproportionate short stature (short neck, curved legs, pectus excavatum) with an initial clinical diagnosis of Turner's syndrome was found to have the karyotype 46,X, + der(X) in 100% of her blood lymphocytes. By means of conventional differential staining (QFH/AcD, FPG, and RBA banding) supplemented with distamycin A treatment, the karyotype of the proband was interpreted as 46,X,t(X;Y) (p22.3;q11). The rearranged marker X chromosome was found to be active in 91% of lymphocytes studied. PCR analysis with Y chromosome specific oligoprimers showed the presence of some Y chromosome long arm DNA in both lymphocyte and gonadal tissue biopsy cells. At laparoscopy the patient was found to have small gonads with a rudimentary uterus and fallopian tubes. Histological examination of gonadal tissue showed primary follicles with dystrophic changes of the germ cells and numerous follicular cysts (polycystic ovaries). The proband's phenotype and its correlation with the genetic imbalance of the rearranged X chromosomes, as well as with non-random t(X;Y) chromosome inactivation, are briefly discussed.

Characterization of a Lectin from Lactarius deterrimus (Research on the Possible Involvement of the Fungal Lectin in Recognition between Mushroom and Spruce during the Early Stages of Mycorrhizae Formation).

A lectin (LDetL) was isolated from carpophores of the mushroom Lactarius deterrimus, a specific symbiont of the spruce, by a combination of affinity, hydroxylapatite, and gel-filtration chromatography. Its molecular mass, as determined by gel filtration, is about 37,000 D, and its structure is dimeric, with two identical subunits assembled by noncovalent bonds. It appeared homogeneous on high-performance liquid chromatography gel filtration, but isoelectric focusing revealed microheterogeneity, with a main band in the pH zone near 6.5. Amino acid analysis showed that LDetL contains a large proportion of glycine and especially methionine. Hapten inhibition assay indicated that LDetL is most specific for [beta]-D-galactosyl(1->3)-D-N-acetyl galactosamine residues. The lectin was formed in the in vitro-cultivated mycelium, and anti-lectin antibodies revealed by indirect immunofluorescence the presence of lectin in the cell wall. Receptor sites for LDetL were found on the roots, especially on the root hairs, of axenically grown spruce seedlings. The lectin LDL previously isolated by us from the taxonomically related mushroom Lactarius deliciosus, a symbiont of the pine, does not bind to the spruce radicle. This suggests a role of the fungal lectin in recognition and specificity during the early stages of mycorrhizae formation.

Isolation and characterization of a lectin from the mushroom, Lactarius deliciosus.

A lectin (LDL) has been isolated from carpophores of the edible mushroom, Lactarius deliciosus, using a combination of affinity chromatography on stromas of group O erythrocytes embedded in polyacrylamide gel and hydroxylapatite, and gel filtration chromatography. Its molecular weight, as determined by gel filtration, is about 37,000 and its structure is dimeric, with two distinct types of subunits (about 19,000 and 18,000). It appeared homogeneous on HPLC gel filtration, but exhibited microheterogeneity on isoelectric focusing. Amino acid analysis revealed that it contains a large amount of glycine. Hapten inhibition assaying indicated that the Lactarius lectin is most specific for D-Gal beta 1----3D-GalNAc. The lectin was found in the mycelium and its possible role in the fungus is discussed.