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At least 613 records · Page 34Linked to original sources
PubMed1997

Distribution of the cytogenetic abnormality +i(3)(q10) in persistent polyclonal B-cell lymphocytosis: a FICTION study in three cases.

Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare entity characterized by a moderate but sustained lymphocytosis where some binucleated or bilobulated circulating forms constitute, even if they are not entirely specific, the cytological hallmark of the disease. An additional chromosome long arm i(3)(q10) has recently been reported as a recurrent cytogenetic aberration, contrasting with a usual polyclonal immunoglobulin expression. To determine more precisely the distribution of the chromosomal abnormality within the peripheral lymphocyte population and study the relationship between the +i(3)(q10) and the bilobulated character, we investigated three new cases of PPBL displaying the cytogenetic abnormality on the karyotype, using a technique of simultaneous fluorescence immunophenotyping and interphase cytogenetics (FICTION). We demonstrated that the +i(3)(q10) was restricted to the B lymphocytes, independently of the kappa or lambda light chain isotype and was present in both bilobulated and non-bilobulated cells. Therefore it is likely that the cytogenetic abnormality occurs at an early stage of lymphocyte differentiation in a precursor cell already committed to the B-cell lineage, before any rearrangement of immunoglobulin genes has taken place.

Adult↗
PubMed2001

Proliferative activity of leukaemic blasts and cytosine arabinoside pharmacodynamics are associated with cytogenetically defined prognostic subgroups in acute myeloid leukaemia.

The biological mechanisms responsible for the association of specific karyotypes with prognosis in acute myeloid leukaemia (AML) remain largely unclear. A prospective study was performed to evaluate how far cytogenetically defined prognostic subgroups of AML differ in their proliferative activity as a potential mechanism for differential sensitivities to S-phase-specific induction chemotherapy comprising cytosine arabinoside (AraC). One hundred and eighty-seven patients with de novo AML were included in the study; 25 patients with a favourable [inv(16), t(8;21), t(15;17)] karyotype, 99 with a normal karyotype, 29 with an unfavourable karyotype (-5, 5q-, -7, 7q-, complex aberrations) and 34 with cytogenetic aberrations of unknown prognostic significance (all others). The favourable group demonstrated the highest ex vivo proliferative activity (PA) (3.41 pmol/105 cells), significantly (P = 0.02) exceeding the unfavourable group with the lowest PA (0.72) and the group with a normal karyotype (1.06) or with karyotype of unknown significance (1.05) that both demonstrated an intermediate PA. Samples with a high PA (> median of the whole group) were more likely to produce interleukin 3, granulocyte macrophage colony-stimulating factor (GM-CSF), granulocyte CSF (G-CSF) (56%, 43% and 50%) than cells with a low PA (33%, 36% and 36%; n.s.). The effect of priming by exogenous GM-CSF or G-CSF was significantly more pronounced in samples with a low PA than in rapidly proliferating samples (P < 0.01). For the whole group, a high PA was closely associated with an increased incorporation of AraC triphosphate (AraCTP) into the DNA (P < 0.0001). Clinically, a high PA was associated with a better complete remission (CR) rate in the normal (95% versus 62%) and the unfavourable group (75% versus 33%). The significant differences in proliferative activity between cytogenetic subgroups of AML are associated with increased cytosine arabinoside pharmacodynamics and constitute one potential mechanism for the different response of cytogenetic subgroups to AraC-based induction therapy.

Adult↗
PubMed2002

Primary effusion lymphomas exhibit complex and recurrent cytogenetic abnormalities.

Cytogenetic findings in a few primary effusion lymphoma (PEL) cell lines have been reported, but only three complete karyotypes of primary specimens from patients with this neoplasm have been published. In this study, cytogenetic analysis was performed on 11 effusion specimens from 10 patients with PEL. We corroborate data obtained from the cell line studies that trisomy 7, trisomy 12 and aberrations in the proximal long arm of chromosome 1 (1q) are recurring cytogenetic aberrations in PEL and also identify breakpoints at 3q23, 7p22, 7q22, 10q24, 12q24, 13q22, 14q24, 14q32, 15p11.2 and Xq22 as well as +8, +15, +19, +X and -Y as recurring chromosome abnormalities. The identification of recurring cytogenetic aberrations may lead to delineation of the genetic events in PEL.

Adult↗
PubMed2002

A study on 289 consecutive Korean patients with acute leukaemias revealed fluorescence in situ hybridization detects the MLL translocation without cytogenetic evidence both initially and during follow-up.

Translocations involving the MLL gene on the chromosome 11 (11q23) are frequently observed in acute leukaemia. The detection of this genetic change has a unique significance as a result of its implication of poor prognosis. To reveal the utility of fluorescence in situ hybridization (FISH) in detecting the MLL translocation, we analysed 289 consecutive Korean patients (children and adults) with acute leukaemias using both conventional cytogenetic analysis (CC) and FISH, placing an emphasis on the result discrepancies. Twenty-two of 289 patients (7.6%) had the 11q23/MLL translocation. In nine of 22 patients (41%), only FISH detected the translocation. In eight of these 22 patients, a total of 19 follow-up examinations were performed, of which FISH detected a significant level of leukaemic cells harbouring the MLL translocation in five patients (26%) without cytogenetic evidence. In addition to the MLL translocation, FISH detected submicroscopic amplification, partial deletion of the MLL gene and trisomy 11 in 12 patients without cytogenetic evidence. In summary, up to 41% of the MLL translocations at initial work-up and 26% during follow-up were detected by FISH without cytogenetic evidence. Thus, we recommend that MLL FISH should be performed in the diagnosis and monitoring of acute leukaemias in combination with CC.

Acute Disease↗
PubMed2003

Cytogenetic heterogeneity of acute myeloid leukaemia (AML) with trilineage dysplasia: Japan Adult Leukaemia Study Group-AML 92 study.

Acute myeloid leukaemia (AML) with trilineage dysplasia (AML/TLD) is de novo AML recognized by the morphological dysplasia of three mature cell lines in the presence of leukaemic blasts. We studied the karyotypes of AML/TLD of patients with de novo AML, except for those with the French-American-British classification M3, who were enrolled onto the Japan Adult Leukaemia Study Group (JALSG)-AML 92 trial. Morphological and cytogenetic analyses were performed in 559 patients and TLD phenotype was found in 155 patients (27.7%). The 511 patients with informative morphological and cytogenetic data were classified into three groups according to karyotype: favourable, intermediate and adverse risk groups (92, 375 and 44 patients respectively). Normal karyotype was the most frequent as a total, and among both the non-TLD and TLD patients (164 patients 45.3% and 78 patients 52.7% respectively). All but one patient with AML/TLD was classified into the intermediate or adverse cytogenetic risk group. TLD phenotype was associated with lower remission rate and shorter overall survival but it did not influence disease-free survival. Although we did not find any specific cytogenetic abnormalities for AML/TLD, the rarity of favourable karyotypes among TLD patients indicates the biological difference between AML/TLD and AML/non-TLD.

Acute Disease↗
PubMed1998

A cytogenetic approach to the differential diagnosis of metastatic clear cell renal carcinoma.

AIMS: To determine by cytogenetic analysis the origins of two clear cell tumours in a 70-year-old Caucasian woman, one in the thyroid gland, and the other in the skin, 16 and 20 years, respectively, after tumour nephrectomy. We sought a conclusive distinction between primary clear cell thyroid carcinoma and its cutaneous metastasis, and between thyroid and cutaneous metastases of clear cell renal carcinoma (RCC). METHODS AND RESULTS: Paraffin sections of the previously formalin-fixed thyroid tumour, and the fresh cutaneous tumour were stained with haematoxylin and eosin (H & E) and periodic acid-Schiff (PAS). Additionally, samples of both tumours were examined electron microscopically. Immunohistochemistry was performed with antibodies against thyroglobulin, pancytokeratin, keratin 7, 8, 18 and 19, chromogranin, calcitonin, CEA, vimentin and EMA. Five to six micrometre sections of both tumours were analysed with alpha-satellite probes of chromosomes 3, 7 and 17 using chromosomal in-situ hybridization (CISH). The cutaneous tumour was also cultured and analysed cytogenetically. The thyroid tumour displayed some follicle-like structures that stained positive with both PAS and antithyroglobulin, giving evidence of possibly entrapped thyroid follicles in metastatic RCC. The cutaneous tumour was negative for both stains. The tumours were ultrastructurally completely devoid of neurosecretory granules. Classical cytogenetical analysis of the cultured cutaneous tumour cells revealed monosomies 3 and 14, well-known specific primary and secondary aberrations, respectively, in clear cell RCC, and hitherto not reported in thyroid carcinomas. CISH of both tumours revealed monosomy 3, indicating a cytogenetical correlation between them. There was no evidence of typical chromosomal aberrations for thyroid carcinomas like structural changes on 10q, structural rearrangements or translocations of chromosome 7. CONCLUSION: Although neither histological sections, nor paraffin blocks of the original nephrectomy specimen were available for review, the original tumour was on record as clear cell RCC. Therefore the two tumours' renal origin was confirmed.

Aged↗
PubMedDate not supplied

[Detection of aberrations in the karyotype of children with acute leukemia: a comparative analysis of cytogenetics and flow cytophotometry].

In the present study a comparative analysis of DNA flow cytometry and cytogenetics was performed in 257 children with acute leukemias to evaluate the comparability of both techniques for the detection of karyotype aberrations. DNA aneuploidies were detected in 88 (34%) patients while cytogenetic anomalies were revealed in 96 (37%) cases. From 76 patients (30%) with cytogenetically inevaluable metaphases 26 (35%) expressed aneuploid DNA stemlines. 67 (79%) of the 85 patients with normal karyotypes or normal modal chromosome numbers had a DNA index of 1.0 while DNA aneuploidies were identified in 18 cases (21%). 4 of 30 patients (13%) with pseudodiploid karyotypes revealed aneuploid DNA stemlines. While aberrations of the chromosome number by 1-3 chromosomes were combined with DNA aneuploidies in 9 of 35 cases (26%) only, all 31 patients with higher numeric chromosome changes also had aneuploid DNA stemlines. These data indicate that cytogenetics and DNA flow cytometry are complimentary methods for the detection of karyotype aberrations and should therefore be applied simultaneously.

Child↗
PubMed1997

The partial tandem duplication of ALL1 in acute myeloid leukemia with normal cytogenetics or trisomy 11 is restricted to one chromosome.

The molecular defects responsible for tumorigenesis in adult de novo acute myeloid leukemia (AML) with a normal karyotype or an additional copy of one chromosome (i.e., trisomy) remain largely unknown. We recently discovered that approximately 90% of adult patients with de novo AML and trisomy 11 (+11) as a sole abnormality and 11% of adult patients with de novo AML and normal cytogenetics carry a molecular rearrangement of the ALL1 (MLL, HRX, or HTRX) gene. The rearranged ALL1 gene has been shown to result from the direct tandem duplication of a portion of ALL1 itself. To better understand the underlying mechanisms of leukemogenesis, we asked whether in cytogenetically normal cases one or both chromosomes carry the mutated allele and whether in trisomic cases the mutation is present in one, two, or three chromosomes. Herein we show that in cytogenetically normal cases of AML and in cases with +11 as a sole cytogenetic abnormality, only one chromosome contains the mutated ALL1 allele. Thus a single mutated ALL1 allele with the partial tandem duplication is sufficient for ALL1-associated leukemogenesis, irrespective of the number of normal genes present. The frequently occurring specific association of +11 and ALL1 gene mutation in the leukemic clone remains unexplained.

Adult↗
PubMed1999

Telomeric fusion is a major cytogenetic aberration of giant cell tumors of bone.

Giant cell tumor of bone (GCT) is regarded as a rare primary bone neoplasm derived from stromal cells, which have the ability to recruit and harbor macrophage and multinucleated osteoclast-like giant cells. Despite being often considered benign, GCT is a problematic neoplasm in that it is aggressive, unpredictable and difficult to treat effectively. Cytogenetically GCT is characterised by a high frequency of telomeric fusion, a process which has been implicated in the production of chromosome instability and tumorigenesis. To extend our knowledge of the significance of telomere association in GCT, the cytogenetics of cell lines derived from spindle-shaped stromal-like mononuclear cells (the tumor cells) of GCT was investigated. Cell lines from three different patients showed telomeric association in all passages. The rate of telomeric association varied from line to line and from passage to passage, but there was no particular pattern to the variations. Many other cytogenetic abnormalities were seen as well as telomeric association, but these were rarely clonal. The nature of most of the other abnormalities seen, such as deleted chromosomes and chromosomes with additional unidentifiable material, was consistent with their being formed as a result of breakage of the dicentric fused chromosomes at a telophase. Chromosomes 13, 14 and 21 were most commonly involved in telomeric fusion. It appears that telomeric association persists in long-term cultures of GCT and is responsible for the accumulation of other associated cytogenetic aberrations. Telomeric reduction and telomerase activity may act as oncogenic events, promoting and sustaining the transformed GCT phenotype.

Bone Neoplasms↗
PubMed2006

Prenatal diagnosis of a cervical teratoma with a cytogenetic study.

We describe a cervical teratoma revealed in the prenatal period that was studied cytogenetically. We were recently confronted with the case of a fetal solid neck mass suggestive of a teratoma. After termination of pregnancy the tumor was studied cytogenetically. This is the first case in the recent literature where a clone of cells with an additional chromosome marker has been detected. Cytogenetic study of the fetal blood in addition to cytogenetic study of the tumor after the termination of pregnancy showed the karyotypes 46,XY and 46,XY/47,XY + m, respectively. Fetal cervical teratoma is a rare condition. Genetic investigation in the case should be considered in order to reveal chromosome rearrangements.

Abortion, Induced↗
PubMed1999

A 6-year experience demonstrates the utility of screening for both cytogenetic and FMR-1 abnormalities in patients with mental retardation.

Cytogenetic abnormalities were found in 81 of 2,757 cases (2.93%) screened for both cytogenetic and FMR-1 mutations because of mental retardation from 1992 to 1997. Of these, 38 (46.9%) were unbalanced autosomal abnormalities, 23 (28.4%) sex chromosomal abnormalities, and 20 (24.7%) balanced autosomal rearrangements. Five subtle deletions were found, of which three involved the long arm of chromosome 7 (7q22-q31.1). Although a high-resolution banding method was used for screening, we concluded that a banding level of 450-550, generally achieved in routine analysis, was sufficient to detect all of these abnormalities. Fragile-X DNA studies revealed CGG expansion mutations in 72 other cases (2.61%). Of the abnormals, 36 (50%) were males and 8 (11.1%) females with full mutations, and 12 (16.7%) were males and 16 (22.2%) females with premutations. Together, our cytogenetic and DNA screening gave 5.5% abnormal results. In this report, these findings are compared with similar surveys of 3,940 subjects from five previous studies. From the combined data of 6,697 cases, this testing approach should reveal nearly equal numbers of cytogenetic and fragile X abnormalities in approximately 6-7% of subjects. It is productive, cost-effective, and consistent with American College of Medical Genetics (ACMG) guidelines for screening of mentally handicapped individuals.

Blotting, Southern↗
PubMed1999

Induction, persistence and modulation of cytogenetic alterations in cells of smoke-exposed mice.

In spite of the major role played by smoking tobacco in the epidemiology of chronic degenerative diseases, it is difficult to mimic the genotoxic and carcinogenic effects of this complex mixture in animal models. We undertook an experimental study evaluating the time-course induction, persistence and modulation of cytogenetic alterations induced in BDF(1) mice exposed whole-body to mainstream cigarette smoke. The animals were divided into five groups, including: (i) 72 sham-exposed mice; (ii) 72 mice exposed to smoke for up to 3 weeks; (iii) 72 mice treated daily with the thiol N-acetylcysteine (NAC, 0.5 g/kg body weight) with drinking water; (iv) 72 mice exposed to smoke and treated daily with NAC, starting 5 days before exposure to smoke; and (v) 48 mice exposed to smoke and treated daily with NAC, starting 1 day after discontinuation of exposure to smoke. After 1, 2, 3, 4, 5, 6, 7, 10 and 14 weeks since the start of exposure to cigarette smoke, eight mice per group were killed, and cytogenetic parameters were evaluated. Exposure to smoke induced a high frequency of micronucleated and binucleated (BN) pulmonary alveolar macrophages, which persisted for at least 14 weeks. The frequency of micronuclei increased early in bone marrow polychromatic erythrocytes, but declined to background levels upon discontinuation of exposure to smoke. By comparison, their induction in circulating normochromatic erythrocytes (NCE) was slightly delayed, less intense but still significant, and persisting for an additional 3 weeks. Administration of NAC, throughout duration of the experiment, strongly inhibited the smoke-induced formation of micronuclei in alveolar macrophages and had some transiently significant effect on the induction of BN macrophages. NAC did not significantly decrease the smoke-induced formation of micronuclei in bone marrow cells, whereas it attenuated the formation of micronuclei in peripheral blood NCE. When given after discontinuation of exposure to cigarette smoke, NAC did not affect the cytogenetic alterations but normalized the altered bronchoalveolar lavage cellularity. The present data provide a detailed analysis of time-related cytogenetic alterations in smoke-exposed mice, both in the respiratory tract and at a systemic level, and show the effects of NAC on these parameters and on the pulmonary inflammatory response.

Acetylcysteine↗
PubMed1986

Enhanced synergism between caffeine and mitomycin C in the induction of cytogenetic aberrations in thymidine kinase-deficient Friend murine erythroleukaemia cells.

The thymidine kinase-deficient subclone, 707BUF, of the Friend murine leukaemia cell line exhibits increased sensitivity to the induction of cytogenetic aberrations by mitomycin C (MMC) relative to wild-type clone 707. It has been suggested that thymidine kinase-deficient cells may be highly mutagen-sensitive through an imbalance of nucleotide pools rendering excision repair error-prone. In this study clone 707 Friend leukaemia cells were compared with subclone 707BUF for sensitivity to the potentiating effect of caffeine on MMC-induced cytogenetic aberrations. The results indicate that although potentiation of mitomycin C-induced cytogenetic damage occurs in both clone 707 and in subclone 707BUF following caffeine treatment, the mutagen-sensitive thymidine kinase-deficient subclone 707BUF had enhanced potentiation by caffeine of MMC-induced cytogenetic damage relative to wild-type clone 707. It is suggested that caffeine may enhance mutagen sensitivity by inhibiting post-replication repair processes and may perhaps also indirectly reduce the effectiveness of the excision repair system by inhibiting the mutagen-induced G2-delay. Clone 707 wild-type cells in the presence of caffeine could then continue to repair DNA damage through an intact though less effective excision repair system, whilst the thymidine kinase-deficient subclone 707BUF would, in the presence of caffeine, be rendered highly mutagen sensitive, being only able to repair DNA damage through an error-prone excision repair process.

Animals↗
PubMed1998

Cytogenetic characterization of the transgenic Big Blue Rat2 and Big Blue mouse embryonic fibroblast cell lines.

The transgenic Big Blue Rat2 and Big Blue mouse embryonic fibroblast cell lines have been used to complement the transgenic Big Blue rat and mouse in vivo mutagenesis assays. However, limited information is available regarding the karyology of these cell lines. Therefore, we have characterized the ploidy, mitotic index, spontaneous frequencies of chromosome and chromatid aberrations and rate of micronucleus (MN) formation in both cell lines. We have also characterized the frequency of sister chromatid exchange (SCE) in transgenic Big Blue mouse cells. Big Blue Rat2 cells are hyperploid and have extremely high baseline frequencies of cytogenetic damage. In addition, Big Blue Rat2 cells are BrdU-resistant, therefore, SCE frequencies cannot be assessed in these cells. We conclude that Big Blue Rat2 cells are not useful for routine cytogenetic toxicology studies. The transgenic Big Blue mouse cell line is polyploid and consistently yields a low mitotic index (approximately 1%) in untreated cells. These mouse cells also exhibited moderately high baseline frequencies of chromosome and chromatid aberrations, however, baseline frequencies of SCE and of MN were not elevated. Transgenic Big Blue mouse embryonic fibroblasts were further studied for MN induction following treatment with N-ethyl-N-nitrosourea (ENU) for 0.5 h at concentrations of 0.425, 0.85 and 1.7 mM. Concentration-dependent increases in MN were observed in these cells. Thus, while an ENU-induced cytogenetic response using transgenic Big Blue mouse cells demonstrates that this cellular model could be used to cytogenetically complement the mutagenesis assays, the low mitotic index and the high spontaneous frequency of chromosome damage confounds its use for routine genetic toxicology studies.

Animals↗
PubMed2003

A new cytogenetic approach for the evaluation of mutagenic potential of chemicals that induce cell cycle arrest in the G2 phase.

The aim of the present study was to develop and standardize a cytogenetic approach for evaluation of the mutagenic potential of chemicals that induce cell cycle arrest in the G2 phase. Even though cytogenetic end-points such as sister chromatid exchange (SCE) have been extensively used to indirectly assess the DNA-damaging potential of various chemicals, they are based on metaphase chromosome analysis. Cells delayed in G2 phase after chemical exposure are not included in conventional SCE analysis. The yield of SCEs obtained, therefore, can be biased, since predominantly undamaged cells proceed to metaphase without delay. To overcome this shortcoming of conventional SCE analysis, the use of a new cytogenetic approach for genotoxic studies is presented that enables the analysis of SCEs directly in G2 phase using drug-induced premature chromosome condensation in cultured peripheral blood lymphocytes. By means of this method, firstly, the possibility that SCE analysis in metaphase chromosomes underestimates the mutagenic potential of various chemicals was tested. Secondly, whether the genotoxic potential of suspected carcinogens could be evaluated using SCE analysis in G2 phase, even at exposures that arrest cells in G2 phase, was examined. Thirdly, whether an important part of the background variation in SCE frequency among individuals is due to the delay of affected cells in G2 phase, rather than to a true biological variation in the cytogenetic end-point used, was tested. The results showed that a higher SCE frequency was scored in G2 phase than in metaphase. Subsequently, the mutagenic potential of chemicals that temporarily arrest cells in G2 phase could now be evaluated more accurately. In addition, it may be of interest to further examine the involvement of cell cycle kinetics in the baseline SCE variation among individuals since a lesser SCE variability was observed when the analysis was carried out in G2 phase rather than at metaphase.

Bromodeoxyuridine↗
PubMed1993

Cytogenetic findings in a metastasizing primary testicular chondrosarcoma.

The first case of a primary chondrosarcoma of the testis is reported. The testicular tumor, 2.5 cm in diameter, metastasized to the retroperitoneal lymph nodes in a 24-year-old male. Histologically, the testicular tumor and the lymph node metastases revealed a well-differentiated chondrosarcoma. Cytogenetic analysis of the retroperitoneal metastases showed a complex chromosomal aberration with two copies of the isochromosome of the short arm of chromosome 12. This is a specific chromosomal anomaly in testicular germ cell tumors. Thus, the cytogenetic analysis proved the germ cell origin of tumor cells as opposed to a possible paratesticular mesenchymal histogenesis. Moreover, the triploid modal chromosomal number of tumor cells confirmed the relationship between polyploidization and a high degree of differentiation in germ cell tumors. These findings stress the clinical relevance of the cytogenetic analysis in at least a subset of cytogenetically well-characterized solid tumors.

Adult↗
PubMed1996

Cytogenetic analysis in peripheral lymphocytes of cancer patients treated with cytostatic drugs: results from an EC Collaborative Study.

Many of the cytostatic drugs commonly used in cancer chemotherapy treatments have been shown to be genotoxic in vivo and in vitro. We present a cytogenetic collaborative study on 13 cancer patients treated with different antitumor agents. For comparison we also carried out a cytogenetic analysis on 14 healthy untreated controls. The frequency of sister chromatid exchanges and structural chromosome aberrations in peripheral blood lymphocytes of the cancer patients was determined prior to the treatment, just after it and 3-7 weeks later. The results obtained show clear differences between the basal levels of cytogenetic alterations in cancer patients, even though the mean value is higher in this group than the basal levels of the group of healthy individuals. Treatment with cytostatics increases the frequency of both cytogenetic biomarkers analyzed, which declined to values similar to those initially observed several weeks after the treatment. Our data are in qualitative and quantitative agreement with other results previously found by other authors.

Adult↗
PubMed1995

Blood specimens from patients referred for cytogenetic analysis: Vanderbilt University experience from 1985 to 1992.

Cytogenetic records were examined from consecutive nononcology blood specimens from 2,821 patients referred for cytogenetic services to Vanderbilt University Medical Center, Nashville, Tenn, from January 1985 to December 1992. We grouped the records according to reasons for referral and diagnoses. The most common reasons for referral were history of multiple abortions/miscarriages (23.3%), possibility of chromosomal abnormality (18.8%), and possible presence of the fragile X syndrome (15.6%). Overall, 2,418 (85.7%) patients were found to have normal chromosomes, and 403 (14.3%) patients were diagnosed with a cytogenetic abnormality. For example, 20 (5.4%) of the 373 males referred for the fragile X syndrome, or 1.4% of all males (20 of 1,428) excluding those with ambiguous genitalia, were diagnosed with this syndrome while 8 (2.1%) of the 373 males had a chromosome abnormality other than the fragile X chromosome. In addition, 85 (70.2%) of 121 males referred for Down syndrome had this syndrome, and only 53 (40.8%) of 130 females referred for Down syndrome had this diagnosis. This study should assist physicians in middle Tennessee and surrounding areas by increasing their awareness of the types and frequencies of cytogenetic diseases and by providing figures for comparison with other regions of the country.

Female↗