High resolution melting analysis for the identification of novel mutations in DKC1 and TERT genes in patients with dyskeratosis congenita.

Dyskeratosis congenita (DC) is a rare inherited bone-marrow failure syndrome with high clinical heterogeneity. Cells derived from DC patients present short telomeres at early ages, as a result of mutations in genes encoding components of the telomerase complex (DKC1, TERC, TERT, NHP2 and NOP10), or the shelterin complex (TINF2). However, mutations have been identified only in around 50% of the cases, indicating that other genes could be involved in the development of this disease. Indeed, mutations in TCBA1 or chromosome segment C16orf57 have been described recently. We have used HRM technology to perform genetic analysis in the above mentioned genes, in Spanish patients showing both, some clinical features of DC and short telomeres. The mutations have been identified by PCR amplification of DC genes followed by high resolution melting (HRM) and direct DNA sequencing analysis. We have identified seven new families with DC, three with X-linked DC and four with autosomal dominant DC, in which we have found two novel mutations in DKC1 (p.His68Arg and p.Lys390del) and four novel mutations in TERT gene (p.Pro530Leu, p.Arg698Trp, p.Arg971His and p.Arg698Gln). The results show that the use of HRM analysis enables a rapid and inexpensive identification of mutations in dyskeratosis congenita associated genes.

Fifty years of cytogenetics: a parallel view of the evolution of cytogenetics and genotoxicology.

A parallelism exists between human cytogenetics and cytogenetic toxicology. The breakthroughs, mostly coming from and used in clinical genetics, are widely used in genetic toxicology. The birth of human cytogenetics occurred in 1956 when it was published that the diploid number of chromosomes in humans is 46. The first stage in chromosome-induced mutagenesis began in 1938 when Sax published the effects of X-rays on the chromosomes of Drosophila. In 1959, the cytogenetic anomalies for Down, Klinefelter, and Turner syndromes were described, and parallelly in 1960, the first publication on chromosomal aberrations in man caused by ionizing radiation appeared. The cytogenetic analysis of chromosomal aberrations in cell cultures is considered one of the primary methods to evaluate induced mutagenesis. At the end of the 1960s, banding techniques allowed chromosomes to be individually identified, in parallel, the sister chromatid exchange analysis technology was described. Another milestone in the history of induced mutagenesis was the discovery that mutagenic agents were able to alter chromosomal division and segregation in gonads inducing meiotic nondisjunction. Here we review new approaches and applications such as biological dosimetry, translocation scoring using FISH, and micronucleus test. Chromosomal aberrations and micronucleus test are now effective cytogenetic biomarkers of early effect used as cancer predictors. Human cytogenetics has proven to be effective over its 50-year lifespan and, although each new technique that has appeared seemed to announce its end, the fact is that the current state of cytogenetics is in reality a collection of techniques that, while common, are cheap, fast, and wide-ranging. Therefore, in genotoxicology, they continue to be useful to identify mutagenic agents as well as to evaluate and analyze exposed populations.

Frequency and characteristics of familial aggregation of Paget's disease of bone.

The cause of Paget's disease of bone (PDB) is unknown. In an attempt to ascertain the proportion of familial cases and evaluate the influence of genetic factors on the occurrence of the disease, a study was undertaken based on 35 PDB patients from our Unit. Their families were investigated, with the participation of a total of 128 first-degree relatives. Fourteen (40%) of these 35 index cases had at least one other first-degree relative affected with PDB and were defined as "familial." The remaining 21 (60%) were considered "sporadic." The frequency of males in the familial cases (79%) was significantly higher than among the sporadics (29%; p < or = 0.01). Mean age at diagnosis (63.1 +/- 12.6 vs. 71.3 +/- 8.7; p < or = 0.02), proportion of polyostotic cases (85.7% vs. 52.4%, p < or = 0.05), and mean number of involved bones per patient (4.36 +/- 2.50 vs. 2.33 +/- 1.93, p < or = 0.01) differ significantly in the familial and sporadic groups. The disease appears to be transmitted via both paternal and maternal sides, and pedigree analysis suggested an autosomal dominant inheritance or multifactorial mechanism. Apart from green-and-blue eye color, which was clearly associated with familial grouping (OR 6.25, 95% CI 1.15-37.16, p < or = 0.01), crude analysis on several genetically based traits and environmental variables revealed no other significant differences between the groups. The adjusted odds ratio estimated for green-and-blue eye color was 2.92 (95% CI 0.38-22.74).(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosome painting in biological dosimetry: assessment of the ability to score stable chromosome aberrations using different pairs of paint probes.

We exposed human peripheral lymphocytes in vitro to 0.3 and 1 Gy of 60Co gamma rays to evaluate whether the ability and sensitivity to detect chromosomal aberrations by chromosome painting is independent or not to the specific paint probes. To detect structural aberrations (translocations), we painted chromosome spreads simultaneously with two whole-chromosome libraries for chromosomes 1, 2, 3, 4, 5, 6, 7, 11, 13, 16, and 18. To compare the rate of chromosome translocations detected by the different pairs of chromosomes, data were normalized according to the fraction of genome painted and evaluated by unconditional logistic regression. Our results show that any combination of paint probes can be used to score induced chromosomal aberrations. We observed that the amounts of translocations are dose dependent and quite homogeneous within each dose of radiation, independently of chromosomes painted. However, the use of small chromosome probes is not recommended because of the high number of cells to be analyzed due to the small amount of genome painted and because it is more difficult to detect translocations in small chromosomes.

Delineation of a duplication map of chromosome 3q: a new case confirms the exclusion of 3q25-q26.2 from the duplication 3q syndrome critical region.

We report on the clinical, cytogenetic, and molecular characterization of a propositus and his mother with a duplication of 3q25-q26, minor anomalies, and mental retardation. The duplication, detected by cytogenetic analysis, was confirmed and delineated by comparative genomic hybridization and fluorescence in situ hybridization using probes previously mapped to the region. Comparison of the mapping data obtained in these patients and those obtained in patients that present with a typical dup(3q) syndrome phenotype shows that the segment duplicated in these patients lies proximally to the reported dup(3q) syndrome critical region, thus explaining the absence in our patients of the characteristic phenotype of dup(3q) syndrome patients. Accumulation of mapping data in patients with segmental duplications of 3q will eventually allow us to build a duplication map of the region and a genotype-phenotype correlation.

Deletion(2)(p23) abnormality in a case of secondary acute myeloid leukemia.

We report a case of acute myeloid leukemia (M5a of the FAB classification), secondary to the myelodysplastic syndrome, showing a deletion of the short arm of chromosome 2 at p23 in the bone marrow cells. In addition, a duplication of chromosome 13,dup(13)(q12q14) was found.

Interstitial del(12)(q15q22) in myelodysplastic syndromes.

A patient with a myelodysplastic syndrome and a 12q deletion was studied and followed-up. After 10 years and several cytogenetic studies, it is suggested that this abnormality can be the sole chromosomal change in myelodysplastic syndromes.

Chromosomal disorder and neoplastic diseases in a family with inherited fragile 16. Causality or casualty?

We describe a family with an inherited fragile chromosome 16 with the concurrence of a constitutional chromosome abnormality, together with neoplastic pathology within the family. The following findings should be pointed out: in relation to the constitutional chromosome pathology, of the proband's 3 children, the eldest daughter was a carrier of the fragile 16, the same as the father, and the second child, a son, had Down syndrome (trisomy 21). Regarding the tumoral pathology of this family, one of the proband's daughters died in childhood from acute lymphoblastic leukemia, whereas the proband developed two different malignant hematologic disorders: a follicular lymphoma and an acute nonlymphocytic leukemia (M5 type). Moreover, two independent acquired chromosome disorders coexisted in the proband; each of these was related to one of the respective hematologic disorders.

Unusual translocations and other changes in acute leukemia.

We report three cases of ANLL and one case of ALL in which we found chromosome abnormalities not previously described. The first patient had a (9;11;16)(p22;q23;p13) translocation in the relapse after bone marrow transplantation. In the second case, a secondary leukemia following a Wilms' tumor, there was a single chromosome anomaly, an inversion of chromosome 13. The third case also presented an isochromosome 13q. In the fourth patient we observed a translocation between two achrocentric chromosomes, as in the third patient, but not of the Robertsonian type: t(21;21)(q22.1;q22.5).

Ph-positive chronic myeloid leukemia with t(8;21)(q22;q22) in blastic crisis.

A patient diagnosed with chronic myeloid leukemia was studied periodically during his illness. The result showed the presence of a Philadelphia (Ph) chromosome by a 9;22 translocation as a single abnormality to the time of blastic crisis. At that time, the chromosome studies showed a clonal evolution. Furthermore, a second derivated line was added to the Ph line. This new anomaly consisted of a 8;21 translocation, considered as specific of M2 type acute nonlymphoblastic leukemia of French-American-British classification.

Trisomy/ tetrasomy of chromosome 8 and +i(8q) as the sole chromosome abnormality in three adult patients with myelomonocytic leukemia.

We report three cases of tetrasomy 8 associated with myeloid disease. Two patients had chronic myelomonocytic leukemia (CMMoL) and the other had acute monocytic leukemia (AML M5 FAB). Two patients had trisomy/tetrasomy chromosome 8 as the sole abnormality. The other patient with CMMoL had two normal 8 chromosomes plus one isochromosome 8q; this is the first case of long arm chromosome 8 tetrasomy without short arm 8 monosomy. This cytogenetic finding suggests the importance of the genes located in the long arms of chromosome 8.

Burkitt lymphoma with a duplication of der(8)t(2;8). Interpretation of a complex karyotype by chromosome painting.

A 51-year-old male patient was diagnosed with Burkitt lymphoma 3 months after cardiac transplantation. The bone marrow karyotype was very complex, and to better define the complex karyotype we used the in situ suppression hybridization technique. Previously we interpreted this karyotype to be: 48,XY,t(2;8)(p11;q24), +der(2)t(2;8)(p11;q24),del(2)(q23), +7, +der(8)t(2;8)(p11;q24), +12, -13, -18, by G banding techniques, with a duplication of the t(2;8) derivatives. After in situ hybridization we changed to a: 48,XY,t(2;8)(p11;q24),t(2;18)(q23;q22), +7, +der(8)t(2;8)(p11;q24), +12, -13, which implies duplication of only one t(2;8) derivative.

Cytogenetic study of neuroendocrine carcinoma of Merkel cells.

We describe the cytogenetic study of a neuroendocrine tumor of Merkel cells which appeared in a patient following a heart transplant. An abnormal karyotype was observed in a metastatic lymph node. The abnormality includes two markers derived from the long arm of chromosome 1, while maintaining two normal chromosomes 1.

Triplication of 1q in Fanconi anemia.

We report herein a 38-year-old male patient with Fanconi anemia but with few phenotypic manifestations--short stature, sterility, and hypoplasic anemia with several years of evolution-who developed a myelodysplastic syndrome (MDS). Bone marrow karyotype showed long arm triplication of chromosome 1 (q12-21q31-q32), and two markers add(11)(p15) and add(21)(q22) which had extra material of chromosome 3 besides the normal chromosome 3 pair. Peripheral blood showed chromosome instability; SCE was normal. Both the patient and his family showed a high prevalence of malignant diseases. 1q duplication and, in a few cases, triplication of 1q has been related to Fanconi anemia, being of unknown significance.

Effect on SCE in human chromosomes in vitro of low-level pulsed magnetic field.

We analyzed sister chromatid exchanges (SCE) frequencies as an indicator of DNA damage induced in human lymphocytes in vitro by a low-level pulsed electromagnetic field. We studied the effect of low-level pulsed electromagnetic fields on human chromosomes with the cytogenetic assay of sister chromatid exchange (SCE) analysis. After the human peripheral lymphocyte cultures were exposed in vitro to the electromagnetic field at different intensities, no significant differences were observed when comparing with the control group as to the number of SCE.

Automatic scoring of sister chromatid exchanges by image analysis in a dose response experiment.

A system which automatically selects second division metaphases and then, automatically scores the number of SCEs of each cell is described. In an initial set of experiments, the performance of the components of the system was measured using a data set in which metaphases had been visually classified as either 2nd division or other; and in 2nd division metaphases, every SCE had been marked on a hard copy. SCE scoring had a true positive rate of about 75% and a false positive rate of about 1.5 false SCEs per metaphase analyzed. Second division detection had a true positive rate of 80% and a false positive rate of about 10% of the non-2nd division cells. Next, the overall system was compared to human visual scoring in a dose-response experiment by analyzing the effect of mitomycin C on human chromosomes scored visually by two observers and by the fully automatic scoring. Human visual scoring and machine analysis showed similar dose responses, but the variability between them was considerable.

Effect of anticonvulsants on human chromosomes. 2. In vitro studies.

The effects of 3 anticonvulsant drugs (diphenylhydantoin, ethosuximide, and phenobarbital) on human peripheral lymphocytes in vitro were studied. The rate of chromosomal aberrations induced by the 3 anticonvulsants was significantly increased from the first concentration analyzed, similar to half the therapeutic serum concentration. These findings are compared with other previous reports.

Development of urologic de novo malignancies after renal transplantation.

OBJECTIVES: The incidence of neoplasms in renal transplant recipients is higher than in general population. The increasing age of donors and recipients also increases the risk of developing malignancies, including genitourinary. The aim of this study is to analyze clinical aspects and management of this complication. MATERIALS AND METHODS: We conducted a retrospective analysis of 1365 patients who underwent renal transplantation between 1977 and 2010 who were 44.6 ± 14.9 years old at the time of transplantation. The median follow-up was 95.6 months (range, 18.0-236.0). Data were analyzed for sex, age, time from transplant to diagnosis, location, clinical stage, immunosuppression, treatment, follow-up, and evolution. RESULTS: We diagnosed 25 de novo urologic neoplasms (25/1365; 1.8%) in 24 patients, with a median follow-up of 32 months (range, 12.5-51.8) from the diagnosis. Sixteen were male (66.7%) and 8 female (33.3%), with a median age at diagnosis of 59 years (range, 56.0-65.5). The median time between the transplant and the diagnosis of the malignancy was 69 months (range, 40.0-116.5). There were 11 renal cell carcinomas (RCC; 11/25; 44%), 8 in native kidney and 3 in renal allograft; 9 prostate cancers (PCa; 9/25; 36%), 8 localized and 1 metastatic; and 5 transitional cell carcinomas (TCC; 5/25; 20%), 3 in bladder and 2 in renal allograft pelvis. Treatments performed were similar to those used in the nontransplanted population. RCC were treated with radical nephrectomy when affecting the native kidney, partial nephrectomy when affecting the allograft, or immunotherapy when metastatic. Patients with localized PCa were treated with radical prostatectomy, radiotherapy, or androgenic deprivation if there were comorbidities, and those metastatic with hormonal deprivation. Bladder TCCs were treated with transurethral resection or radical cystectomy. Pelvis TCCs affecting the allograft were treated with radical nephroureterectomy of the allograft including bladder cuff and pelvic lymphadenectomy. CONCLUSIONS: There exists an increased incidence of urologic tumors in kidney transplant recipients. Conventional treatments of these tumors are technically feasible. The risk of developing these tumors remains even in the long term. Because of their suitability for curative treatments, it is advisable to perform periodic screening for urologic cancers to achieve an early diagnosis.

Phenotypic characterization of hereditary epithelial ovarian cancer based on a tissue microarray study.

The pathologic and immunohistochemical features of familial epithelial ovarian cancers are not well understood. We have carried out a comprehensive immunohistochemical study of familial ovarian carcinomas from women with and without BRCA1 or BRCA2 mutations, in order to identify specific and/or common features among these different familial case groups (BRCA1, BRCA2 and non-BRCA1/2) and to identify markers of diagnostic value that might help to select more specific treatments. 73 familial primary ovarian carcinomas were analyzed for the expression of 40 antibodies involved in different genetic pathways using a tissue microarray. Serous carcinomas comprised the majority of all three familial case groups. On the other hand, BRCA1 and BRCA2 carcinomas have similar histopathologic features; i.e. they are often high-grade and are usually diagnosed at a more advanced FIGO stage than non-BRCA1/2 carcinomas. In our series, BRCA1 carcinomas had better clinical evolution and they also more frequently over-expressed PR and P53 than BRCA2 and non-BRCA1/2 carcinomas. Unsupervised cluster analysis and survival analysis identified ERCC1 as a potential marker of better clinical outcome for hereditary epithelial ovarian cancer.