The most frequent chromosomal abnormalities in karyotypes of patients with reproductive disorders

Cytogenetic and molecular cytogenetic characteristics have been studied in 210 couples with fertility problems. The patients’ karyotypes contained various chromosomal rearrangements in 46 cases (10.95%). The structural chromosomal rearrangements such as pericentric inversions, Robertsonian translocations, balanced reciprocal translocations, and marker chromosomes were more frequent than numerical chromosome aberrations (89.13 and 10.87% of cases, respectively). We have found 19 (4.52%) karyotypes with “hidden’ low mosaicism in X and Y chromosomes. We believe that the patients with chromosomal anomalies in the karyotype need differentiated treatment.     

Prognostic significance of additional chromosomal abnormalities in Ph positive bone marrow cells in chronic myeloid leukemia

We studied the prognostic significance of combination of different chromosomal abnormalities and genomic mutations in Ph+ chronic myeloid leukemia patients. In general 49 cytogenetic analyses of bone marrow aspirate from 35 patients (11 of these observed in dynamics) have been carried out. The additional chromosome changes were found in 25.07% cases and approximately 80% of anomalies appeared in the blast phase. Among the secondary chromosomal abnormalities extra Ph-chromosome appeared mostly in different combinations with trisomy of chromosomes 8 and 19. Appearance of clonal differences of cells, high rate of genome mutations and of microchromosomes had negative prognostic significance on disease proceeding.     

An unexpected high frequency of trisomic fetuses in 229 pregnancies monitored for advanced maternal age

Summary In 229 pregnancies monitored because of advanced maternal age, 16 (7%) abnormal fetal karyotypes were detected. We found 13 cases of trisomy 21, twice a trisomy 18, and once an additional marker chromosome. The frequency of abnormal fetal karyotypes in different maternal age groups was found to increase from 1:20 at 38–40 years, to 1:16 at 41–43 years, and finally to 1:45 in women of 44–46 years. The overall incidence of chromosomal aberrations and specifically of trisomy 21 is considerably higher than that described in retrospective studies.     

SNP analysis of minimally evolved t(14;18)(q32;q21)-positive follicular lymphomas reveals a common copy-neutral loss of heterozygosity pattern

Follicular lymphoma (FL) cases with a t(14;18)(q32;q21) and minimal or no additional karyotypic alterations, such as copy number gains and losses and/or chromosomal rearrangements, may exhibit pathologic features and a clinical behavior similar to those with more complex karyotypes. This study sought to investigate whether the copy-neutral loss of heterozygosity (cnLOH) profiles of these minimally evolved t(14;18)(q32;q21)-positive follicular lymphoma (MEV-FL) cases are similar to or different from the majority of FL cases with more karyotypic alterations. Affymetrix SNP 6.0 array analysis was applied to the tumor genomes of 23 MEV-FL biopsy samples to assess for the presence of cnLOH. These cases carried either a single or no chromosomal abnormality in addition to t(14;18)(q32;q21) as determined by karyotyping. We found that, although these MEV-FL cases had simple karyotypes, they showed very similar cnLOH profiles as compared to cytogenetically complex cases. The most frequent regions affected by cnLOH were 1p (17%), 6p (17%), 12q (13%) and 16p (13%). Our study suggests that cnLOH alterations may serve as important contributors to the pathological and clinical manifestations of FL.     

Electrophoretic karyotypes of some species of the genus Leptomonas (kinetoplastida, trypanosomatidae), homoxenous trypanosomatids parasites of insects

Electrophoretic karyotypes of homoxenous trypanosomatids Leptomonas peterhoffi, L. mycophilus, L. nabiculae and Leptomonas sp. have been studied by transverse alternating-field electrophoresis under varying electrophoretic conditions. From 12 to 17 chromosomal DNA bands, ranging from 370 to more than 1500 kb were detected in the karyograms of the species compared. In each pattern, some intensely stained bands could represent more than one chromosome. Taking into account the number of intensely stained bands, the karyotype of L. peterhoffi was estimated to contain at least 18 chromosomes, the karyotypes of L. mycophilus and L. nabiculae, at least 21 chromosome each, and the karyotype of Leptomonas sp. up to 20 chromosomes. Interclonal variations of electrophoretic karyotypes of 10 clones of Leptomonas sp. (cfmI-cfmX) were studied. Seven of ten clones had identical electrophoretic patterns. In the karyograms of three clones (cfmI, cfmVI, cfmVII), additional chromosomal DNA bands were observed. The obtained results suggest, that electrophoretic karyotypes cannot be used as reliable markers of species of homoxenous trypanosomatids, since intraspecies variability does occur in these parasites.     

Transabdominal chorionic villus biopsy in second and third trimesters of pregnancy to determine fetal karyotype.

Transabdominal chorionic villus biopsy is an established method of obtaining material for analysing fetal chromosomes in the first trimester of pregnancy but has not been widely used for karyotyping in the second and third trimesters, when rapid results are required. The technique was evaluated in two groups of patients, comprising 106 at risk of having a fetus with chromosomal anomalies (105) or X linked disease (one) studied between 13 and 22 weeks (median 15 weeks) of gestation (group 1) and 21 with abnormal fetal findings on ultrasonography studied between 13 and 38 weeks (median 27 weeks) (group 2). Chorionic tissue was collected at the first attempt in 109 patients and at the second attempt in a further 17 independent of the position of the placenta. In one case from group 1 sufficient material for analysis could not be obtained. Seven abnormal karyotypes (six in group 1 and one in group 2) were diagnosed. Karyotyping was unsuccessful in two cases in group 1 (at 17 and 18 weeks'' gestation) and in two in group 2 (at 29 and 38 weeks'' gestation). Follow up of group 1 four weeks after sampling showed no signs of adverse fetal development apart from one unexplained intrauterine fetal death. The findings suggest that chorionic sampling is a safe and valuable additional technique for the late detection of chromosomal defects.     

Variations of Candida albicans electrophoretic karyotypes.

We previously described 14 rare spontaneous morphological mutants of Candida albicans that were associated with chromosomal aberrations (E. P. Rustchenko-Bulgac, F. Sherman, and J. B. Hicks, J. Bacteriol. 172:1276-1283, 1990). Improved conditions for separation of chromosomes, as well as hybridization probes, were used to investigate the variation of karyotypes of clinical isolates and additional morphological mutants. All 23 newly analyzed morphological mutants, representing frequently occurring and highly unstable colonial forms, had a variety of altered karyotypes. All chromosomal changes were similar to those previously observed in mutants m1 to m14. In this study, I particularly noted that the most frequent changes involved the long chromosome VIII, which carries ribosomal DNA cistrons. Two rates of instability were uncovered by analyzing the progenies from two highly unstable mutants. An unstable mutant proved to be able to continuously produce a large number of altered karyotypes that could result in a wide variety of different phenotypes. Furthermore, all four independent clinical isolates, FC18, C9, 3153A, and WO-1, common laboratory strains, revealed different electrophoretic karyotypes and distinct colonial morphologies on a synthetic medium, similar to spontaneous mutants. The differences of electrophoretic karyotypes observed among clinical isolates resembled the changes found among different kinds of spontaneous morphological mutants. These findings contribute to the understanding of natural karyotypic variability and are in agreement with the hypothesis that chromosomal alterations observed spontaneously under laboratory conditions provide this amictic species with genetic variability in nature.     

Chromosomal instability of SV40-transformed human prostatic epithelial cell lines

Three SV40-transformed derivatives (G1, T2, and T5) of human prostatic epithelial cells were analyzed karyotypically. For comparison, an SV40 derivative (TA) obtained from isogenic fibroblasts, was also studied. The chromosome complements of these cells, as well as a sub-clone of T2 isolated in soft agar (T2-A5), were analyzed using banding techniques. Numerical as well as structural changes were observed in all transformed cultures. Karyotypic changes in all cells at a given passage level appeared to be random. On the other hand, characteristic differences in modal chromosome number, and type and number of abnormal chromosomes were observed among the different lines. Most cells of two of the three epithelial lines (T1 and T2) were either hypo- or pseudodiploid, whereas T5 consisted of a mixed hypodiploid and hypotetraploid population. The TA subline was also predominantly hypo- and pseudodiploid. Dicentrics, telomeric associations, translocations, and loss of chromosomes were the most prominent abnormalities. The loss of chromosome 18 was characteristic for all epithelial lines. All T1 and T5 cells had lost either one or both copies of the 18. While individual cells of the original T2 line had random karyotypes, most of T2-A5 cells had a relatively uniform karyotypic pattern. They also had a similar pattern of abnormal chromosomes. These observations suggest that culture in soft agar may have selected a particular chromosomal variant. We conclude that transformation of prostatic epithelial cells by SV40 may bring about site-specific as well as random chromosomal changes. These changes could reflect either intermediate or sequential stages in progression to neoplasia.     

Association of pigmentary anomalies with chromosomal and genetic mosaicism and chimerism.

We have evaluated eight patients with pigmentary anomalies reminiscent of incontinentia pigmenti or hypomelanosis of Ito. All demonstrated abnormal lymphocyte karyotypes with chromosomal mosaicism in lymphocytes and/or skin fibroblasts. In seven the skin was darkly pigmented, and in all of these seven cases the abnormal pigmentation followed Blaschko lines. The literature contains at least 36 similar examples of an association between pigmentary anomalies and chromosomal mosaicism, as well as five examples of an association with chimerism. The pigmentary anomalies are pleomorphic, and the chromosomal anomalies involve autosomes and sex chromosomes. The pigmentation patterns are reminiscent of the archetypal paradigm seen in allophenic mice and demonstrate the clonal origin of melanoblasts from neural crest precursors. Patients with anomalous skin pigmentation, particularly when it follows a pattern of Blaschko lines, should be appropriately evaluated for a possible association with chromosomal or genetic mosaicism or chimerism.     

Induced leukemias and their connection with radiation exposure

The cytogenetic study of bone marrow cells was performed in 40 patients with secondary leukemias which have arisen after application of cytostatic and/or radiotherapy for primary tumours (Hodgkin's disease, lymphomas, acute lymphoblastic leukemias, breast cancer and other solid tumours). The comparative analysis of results has shown, that the leukemias after irradiating or application of alkylating agents and irradiation, have the quite particular clinico-morphological and cytogenetic characteristics. In 70% of cases these diseases develops as smouldering leukemias with subsequent transformation in M-4, M-6, and rarely M-2 cytochemical variants. Primary cytogenetic events in 60% of researched karyotypes are the losses of long arms or whole chromosomes 5 and 7. In 20% of the researched cases normal karyotype was found, in the left 20%, the changes of a karyotype not including anomalies 5 and 7 chromosomes were detected. The obtained outcomes allow to consider the discharged complex of tags as reference for leukemias, induced by irradiating or chemical agents with similar mechanism of action (alkylating agents, benzene and its derivates). This complex of tags is typical for induced leukemias, and in a combination with definition of a level of stable aberrations in peripheral blood lymphocytes, can be utilised for abjection of radiation-induced leukemias from common mass of cases detected in regions, polluted by radionuclides. In this study in 60% of cases only specific for secondary leukemias chromosomal aberrations, including monosomy 5 and 7, rearrangements of 11q23 were found. On the base of the obtained data the differences in concepts of "secondary" and "induced" leukemias are considered.     

A clinical and cytogenetic investigation carried out in a special institution for mentally retarded patients: preliminary results concerning 82 cases of oligophrenia (author's transl)]

A clinical and cytogenetic investigation carried out in a special institution for mentally retarded patients revealed 82 cases of oligophrenia, amongst whom were found 56 normal karyotypes (68.3%). Out of 25 karyotypes with chromosome anomalies or variants there were 18 cases of trisomy 21 and 7 others: one case of mosaicism with balanced translocation, 46,XX/46,XX,6p+,17q-; one case of partial trisomy, 46,XX,11q+; one case of pericentric inversion, 46,XY,inv(1) (p13,q21); one case with 8% chromosome breaks; three cases of marker chromosomes, of which one was of karyotype 46,XX,1qh+, and two (oligophrenic sisters) 46,XX,21p+. Moreover, there was an interesting case of testicular feminisation in a 9-year-old girl with karyotype 46,XY. The authors' results corroborate those obtained in several important previous studies based on much larger numbers of patients. Amongst the 56 cases where the karyotype was shown to be normal, there were 15 for whom a probably exogenic cause of the oligophrenia could be established, occurring mainly during the perinatal period. The authors were also able to confirm that the genetic factor plays an important role in the incidence of mental retardation, since in 22 examined patients, i.e. 26.8% of all cases, the condition was of familial type. Some interesting observations of idiopathic oligophrenia are reported, as well as several cases with well-known syndromes (Crouzon's and Cornelia de Lange's syndromes, hypothyroidism). Two cases of incest between father and daughter, which had produced children with serious oligophrenia associated, in one case, with deaf-mutism, microphthalmia, microcephaly and sclerocornea, are also discussed. The data show that mental retardation can frequently have a genetic cause, either of mendelian, chromosomal or multifactorial origin.     

Mechanisms of maternal aneuploidy: FISH analysis of oocytes and polar bodies in patients undergoing assisted conception

We have examined unfertilised oocytes and their first polar bodies (PBs) to determine the way in which the frequency of whole chromosome imbalance compares with that involving single chromatids and whether the precocious separation of chromatids prior to anaphase I affects all pairs of chromosomes. We have applied the technique of fluorescent in situ hybridisation in a three-stage method by using locus-specific probes for chromosomes 13 and 21 and alpha-satellite probes for chromosomes 1, 9, 16, 18 and X to determine the chromosome status of oocytes and their PBs. We obtained analysable results from 127 oocytes and 57 PBs from 72 patients of average age 33 years. Six oocytes and three PBs had extra signals but, of these, three were derived from a single patient, aged 26. Anomalies were seen in chromosomes 13, 16, 18, X and, notably, 21 but none were observed in chromosomes 1 and 9. Half of the anomalies involved additional chromatids rather than whole chromosomes. Since particular chromatids were found to be prematurely separated in the metaphase II oocyte, this may provide further evidence for an additional mechanism of maternal aneuploidy that operates at anaphase II. Detailed analyses of both oocytes and PBs have elucidated possible mechanisms leading to aneuploid gametes in this group of patients with fertility problems.     

Human sperm chromosome complements in chemotherapy patients and infertile men

Our studies of human sperm karyotypes and interphase sperm analyzed by fluorescence in situ hybridization (FISH) have both yielded estimates of disomy frequencies of approximately 0.1% per chromosome with an overall aneuploidy frequency in human sperm of approximately 5%–6%. However, the distribution of aneuploidy in sperm is not even, as our data from sperm karyotypes and multicolour FISH analyses both demonstrate a significant increase in the frequency of aneuploidy for chromosome 21 and the sex chromosomes. We have studied men at increased risk of sperm chromosomal abnormalities including cancer patients and infertility patients. Testicular cancer patients were studied before and 2–13 years after chemotherapy (CT) with BEP (bleomycin, etoposide, cisplatin). Sperm karyotype analysis on 788 sperm demonstrated no significant difference in the frequency of numerical or structural chromosomal abnormalities post-CT vs pre-CT. Similarly, multicolour FISH analysis for chromosomes 1, 12, XX, YY and XY in 161,097 sperm did not detect any significant differences in the frequencies of disomy before and after treatment. However, recent evidence has suggested a significant increase in the frequency of disomy and diploidy during CT. We have found that infertile men, who would be candidates for intracytoplasmic sperm injection, have an increased frequency of chromosomally abnormal sperm karyotypes. Also, FISH analysis for chromosomes 1, 12, 13, 21, XX, YY and XY in 255,613 sperm demonstrated a significant increase in chromosomes 1, 13, 21, and XY disomy in infertile men compared with control donors. Received: 4 July 1998; in revised form: 7 September 1998 / Accepted: 8 September 1998     

Detection of chromosome aberrations in metaphase and interphase tumor cells by in situ hybridization using chromosome-specific library probes

Summary Chromosome aberrations in two glioma cell lines were analyzed using biotinylated DNA library probes that specifically decorate chromosomes 1, 4, 7, 18 and 22 from pter to qter. Numerical changes, deletions and rearrangements of these chromosomes were radily visualized in metaphase spreads, as well as in early prophase and interphase nuclei. Complete chromosomes, deleted chromosomes and segments of translocated chromosomes were rapidly delineated in very complex karyotypes. Simultaneous hybridizations with additional subregional probes were used to further define aberrant chromosomes. Digital image analysis was used to quantitate the total complement of specific chromosomal DNAs in individual metaphase and interphase cells of each cell line. In spite of the fact that both glioma lines have been passaged in vitro for many years, an under-representation of chromosome 22 and an over-representation of chromosome 7 (specifically 7p) were observed. These observations agree with previous studies on gliomas. In addition, sequences of chromosome 4 were also found to be under-represented, especially in TC 593. These analyses indicate the power of these methods for pinpointing chromosome segments that are altered in specific types of tumors.     

Cytogenetic study of twelve human near-diploid breast cancers with chromosomal changes

The karyotypes of 12 fresh breast cancers, including two of the male, selected for their near-diploidy and their slight number of anomalies, i.e. less than 10 rearranged chromosomes, are reported. A clonal evolution could be demonstrated in 4 cases. Most of chromosomal imbalances result from structural rearrangement, frequently after breakage in juxtacentromeric heterochromatin. There does not seem to exist a specific breakpoint, but many of the imbalances are recurrent. They are, by decreasing order of frequency: gain of 1q, (7 cases), losses of 11q, 16q and 1p (5 cases), losses of 8p and 13q (4 cases), gain of 8q and losses of 6q and 17p (3 cases). None of these anomalies can be regarded as primary, but they are likely to be selected because they confer a slight selective advantage for the carrier cells during the tumoral progression.     

Chromosomes in the Cornelia de Lange syndrome

Summary This paper summarizes previous chromosomal studies in patients with the Cornelia de Lange syndrome showing abnormal karyotypes. We report on 45 cases of the Cornelia de Lange syndrome clinically examined by one of us (B. B.) and chromosomally studied using several different methods. Two abnormal karyotypes were found: a girl with a 45,X karyotype and a boy with a (13q14q) translocation which was also found in his phenotypically normal mother and maternal grandmother. Because of recent reports of the duplication 3q syndrome and Comelia de Lange-like phenotypes, prometaphase chromosomes were studied in 31 patients. All karyotypes were normal. As there was an excess of boys among the younger patients, special examination for the fragile site on X(q28) was carried out. This abnormality was not found. Even though no patients with the dup(3q) syndrome were found among the Cornelia de Lange patients, chromosome studies are recommended especially in connection with genetic counselling. A recurrence rate of 2–5% must still be considered for the Cornelia de Lange syndrome.     

Chromosomes and Transformation of Lymphocytes in Lymphoproliferative Disorders

In chronic lymphocytic leukaemia the majority of circulating lymphocytes which responded to phytohaemagglutinin in vitro were found to have normal karyotypes. A minor population of cells in patients treated with chemotherapy had an increased number of chromosomal rearrangements as compared with cells from normal controls and untreated patients with chronic lymphocytic leukaemia. Probably bonemarrow and lymph-node cells also had a normal karyotype.In the other lymphoproliferative disorders the peripheral blood lymphocytes had either normal karyotypes or chromosomal abnormalities attributable to treatment, even in those cases where the tumour cells of involved lymph nodes were known to have abnormal karyotypes.It was possible that circulating tumour cells were present in one case.     

Robertsonian Translocations: An Overview of 872 Robertsonian Translocations Identified in a Diagnostic Laboratory in China

Robertsonian translocations (ROBs) have an estimated incidence rate of 1/1000 births, making this type of rearrangement the most common structural chromosomal abnormalities seen in the general population. In this study, we reports 872 cases of ROBs from 205,001 specimens karyotyped postnatally in a single accredited laboratory in China, including 583 balanced ROBs, 264 unbalanced ROBs, 9 mosaic ROBs, and 18 complex ROBs. Ninety-three percent of the balanced ROBs observed were adults with infertility, miscarriage, or offspring(s) with known chromosomal abnormalities. Significant excess of females were found to be carriers of balanced ROBs with an adjusted male/female ratio of 0.77. Ninety-eight percent of the unbalanced ROBs observed were children with variable referral reasons. Almost all of the unbalanced ROBs involved chromosome 21 except a single ROB with [46,XX,der(13;14),+13] identified in a newborn girl with multiple congenital anomalies. Multiple novel ROB karyotypes were reported in this report. This study represents the largest collections of ROBs in Chinese population.     

The prevalence of cytogenetic anomalies in children with congenital developmental defects (CDD)

The analysis of the cytogenetic anomalies frequencies in children with inborn defects of development was carried out, and the comparative evaluation of involving in cytogenetic anomalies of the individual chromosomes was determined. Chromosomes 9, 13 and 18 were most frequently involved in chromosomal anomalies. There no direct relations were revealed between peculiarities of inborn defects of development and definite cytogenetic anomalies.