8q22-->qter duplication in a child with multiple congenital malformations: case report.

BACKGROUND: Congenital malformation syndromes are often caused by unbalanced chromosome translocations, which appear spontaneously or may be inherited from a healthy parent being the carrier of a balanced reciprocal translocation (rcp). Breakpoints, underlying chromosome fragment exchanges, may be located at any point of any chromosome and therefore, an infinite number of different translocations is possible. Special emphasis is placed both on the clinical characterization of every rare chromosomal aberration syndrome and on the determination of its breakpoints. OBJECTIVES: Diagnosis of a 8q22-->qter duplication in a child with multiple congenital malformations. MATERIAL AND METHODS: We determined the karyotypes of the five members of proband's family were established by using classical cytogenetic methods on whole blood obtained by venipuncture. RESULTS: We described a rare familial reciprocal translocation t(8; 14), observed in balanced form in mother and one healthy son, while being unbalanced in the son with congenital malformations. CONCLUSIONS: Balanced chromosome 8 aberration carriers should be aware of the procreation risks and need genetic counseling.

Classical and molecular cytogenetics in analysis of diepoxybutane-induced chromosome aberrations.

The genotoxic properties of diepoxybutane (DEB) have been extensively studied by many authors. The most often investigated endpoints were sister chromatid exchanges (SCE) and micronuclei (MN), and less frequently, chromosome aberrations (CAs). In the present study, the analysis of CAs induced by DEB in vitro on human whole blood lymphocytes was performed by using three methods of chromosome visualisation: Giemsa-staining, GTG banding and chromosome painting (FISH). The results showed that DEB is a very efficient clastogenic agent and induces chromosome breaks and gaps as well as tri- and quadriradials (observed by using classical cytogenetic methods) together with acentrics (observed by using FISH) on the statistically significant level, as compared to controls (chi2-test, p<10-5). The analysis of GTG-banded metaphases revealed that the break-points were distributed non-randomly within the chromosomes and located mainly in 1p, 1q, 2p, 2p, 6q, 9q and 14q (p<10-6). In conclusion it can be stated, that methods applied in this work are complementary and can be used successfully for estimation of the clastogenic potential of the tested chemical.

Chromosome instability in head and neck cancer patients.

Genetic changes play a crucial role in the process of neoplastic transformation. Mutations may occur spontaneously, but most of them (60-90%) are induced by mutagens. The epidemiological data indicate that only a part of the population exposed to mutagens/carcinogens develops cancer. Studies of the mechanisms leading to individual sensitivity to mutagens as well as tests allowing to recognize individuals susceptible to cancer have been performed. The bleomycin test is widely used for this purpose. In this classical test introduced by Hsu et al, the mean number of breaks per cell is analysed. In our study we present first results of the bleomycin test in patients suffering from head and neck cancer. In these patients, an increased number of breaks/cell (1.22 +/- 0.5 vs 0.79 +/- 0.3 in the control group) and an increased number of damaged cells (47% vs 36%) were observed. The results were also analysed in regard to the clinical stage of the disease. The data suggest that the chromosome instability does not correlate with the progression of the disease.