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.

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.

Aspects of intracranial and spinal tumors in patients with Down syndrome and report of a rapidly progressing Grade 2 astrocytoma.

BACKGROUND: Brain tumors in patients with Down syndrome (DS) rarely are reported, and their behavior is not well known. METHODS: The authors report on a male patient age 19 years who had DS with diffuse astrocytoma (World Health Organization Grade 2) that recurred twice despite treatment, leading to a glioblastoma and, finally, to death in just over 2 years. The literature on brain tumors in patients with DS is reviewed. RESULTS: Although brain neoplasms were suspected to be in excess in patients with DS, the authors found only 36 patients with brain neoplasms and 2 spinal tumors. An unusual distribution of histologic tumor types, with an over-representation of germ cell and mesenchymal tumors and a lack of embryonal tumors, was observed, in agreement with what is known currently about the tumor profile of patients with DS. CONCLUSIONS: Cerebral tumors in patients with DS have a specific distribution and may behave differently compared with the general population. These features may be related to the gene dosage effect of oncogenes, antioncogenes, and genes involved in cerebral development due to the supernumerary chromosome 21.

A tumor profile in Down syndrome.

We conducted a review of cancers in Down syndrome (DS), because solid tumors are poorly understood in DS. Cancers are in excess in this condition because of the 20-fold excess of leukemias, whereas malignant solid tumors seem to be globally underrepresented as compared with those in the general population. However, among these tumors, some tumors are in excess: lymphomas, gonadal and extragonadal germ cell tumors, and possibly retinoblastomas and pancreatic and bone tumors. Neoplasms in excess are seen earlier, sometimes in fetal life (leukemias and testicular germ cell tumors) or neonatally (leukemias and lymphoma) and affect mainly male subjects. There seems to exist an excess of rare karyotypes. Other tumors are underrepresented, particularly neuroblastomas and nephroblastomas, in young children, and perhaps common epithelial tumors in adults. These observations suggest that DS has a particular tumor profile, with some tissues more affected by malignant diseases (hematopoietic tissue and germ cells) and others that seem to be protected (central and peripheral nervous system, renal tissue, and epithelial tissues). The mechanism is mainly genetic, but differences in exposure to exogenous agents compared with the general population must be kept in mind. These findings are of interest for the management of these patients and early detection of cancers. Better knowledge of this tumor profile could help us to understand the mechanisms of carcinogenesis and should be compared to the current knowledge of genes on chromosome 21.

Fluorescent in-situ hybridization and sequence-tagged sites for delineation of an X:Y translocation in a patient with secondary amenorrhoea.

We describe a phenotypically normal female with secondary amenorrhoea due to a translocation of genetic material involving the long arm of chromosome X (Xq28) and the long arm of chromosome Y (Yq11). We used fluorescent in situ hybridization to localize the breakpoint on the Xq. The Y chromosome breakpoint was identified using polymerase chain reaction (PCR) detection of sequence-tagged sites (STS) specific for interval 5 at Yq11.21. The relationship between this X:Y translocation and premature ovarian failure is discussed.

A case report of Down syndrome and centroblastic lymphoma.

We describe a case of left cervical stage I centroblastic lymphoma in a 29-year old male patient with Down's syndrome due to a (14; 21) Robertsonian translocation. The disease presented as extensive lymph node necrosis leaving rare areas of tumor cells, accounting for the diagnostic difficulties. According to our review of the literature, lymphoma is one of the most common neoplasms in DS patients and may represent the second most common malignancy in this condition, far behind leukemia.

A history of miscarriages and mild prognathism as possible mode of presentation of mosaic trisomy 18 in women.

A 22-year-old woman seeking medical assistance for hypofertility after two miscarriages had very slight anomalies: mild macrogenia and prognathism, and temporal depilation. Peripheral lymphocytes and fibroblastic karyotypes disclosed the tenth published case of low-level mosaicism for trisomy 18 with normal intelligence. Subfertility is frequently observed among these patients. As women with this anomaly are at risk of trisomy 18 pregnancies and as five cases have been reported recently, this particular chromosomal anomaly may not be so exceptional and should be investigated in cases of hypofertility.

Hepatic calcifications in a fetus with trisomy 9 that underwent cordocentesis.

Foci of calcification were observed at autopsy in the liver of a fetus with complete trisomy 9 on which two cordocenteses had been performed. It is suggested that liver calcifications are a possible complication of the procedure. As several other cases of calcifications in the liver and other organs of fetuses with autosomal trisomies have been described without a history of cordocentesis, further studies should be carried out to determine whether fetuses with chromosomal anomalies are more prone to thrombus formation and embolization.

Chromosome analysis by image processing in a computerized environment. Clinical applications.

Dealing with a routine regional cytogenetic activity, we have developed and adapted to clinical work a semi automatic karyotyping machine. Attempts for an accurate automated chromosome classification using a neural network have led to partial results. A specific adaptation to cancer cytogenetics is under development (determination of the modal number, translocations analysis with densitometric curves, automatic identification of markers). A specific program allows quantification of chromosome labelling with radioactive probes. Exchanges of digitized karyotypes are feasible with labs using automated karyotyping machines. A local network connects several karyotyping and metaphase finding stations. Guidelines for an international data bank concerning abnormal chromosome images have been elaborated. On the other hand the ISH techniques have been applied to the following topics: identification of human chromosome aberrations in amniotic and chorionic cells, chromosome studies of human gametes and embryos (including sex determination), identification of markers in cancer cells.

[Complete and homogenous trisomy 9 detected in utero]. / Trisomie 9 totale et homogène dépistée in utero.

During a gestation with oligoamnios and growth retardation noticed at 25th week an amniocentesis allowed us to discover the 14th case of complete trisomy 9, the third detected in utero. It is also the first without heart malformation, otherwise phenotype was usual. The liver had small areas of necrosis with calcifications and slight fibrosis which may be in relation with two cordocentesis made before expulsion. The important phenotype alterations and poor outcome of fetuses with trisomy 9 justify elective abortion.

[Chromosome analysis using image processing. Recent aspects and perspectives]. / L'analyse chromosomique par traitement d'images. Aspects récents et perspectives.

After a brief description of the automatic metaphase finding and karyotyping systems actually available, the authors describe an interactive method for chromosome analysis. The edges of each chromosome are delineated automatically. The use of 256 grey levels and 512 x 512 pixels allows the accurate classification. The result may be recorded on hard copy, videotape or disk. Present improvements of the Chromoscan include histograms, quantitative studies and the use of an expert system.

A dicentric t (22;22) translocation associated with recurrent abortions and a normal fetal karyotype

Descreve-se uma translocaçäo dic (22;22) (pter;pter) em uma paciente que apresentou abortos espontâneos múltiplos. A constituiçäo cromossômica normal de un dos fetos abortados provavelmente resultou da dissociaçäo deste cromossomo translocado

[A new system of chromosome analysis by image treatment: the chromoscan]. / Un nouveau système d'analyse chromosomique par traitement d'images: le chromoscan.

The authors present a new interactive system for chromosome analysis. All the operations are checked by the biologist with the use of a "mouse". This system avoids the photographic work and the manual classification. Its main interest is to carry out quickly the karyotype after the slide preparation.

Translocation t(3;20) associated with thrombocythemia in Ph-positive CML.

A patient with Philadelphia (Ph) chromosome positive chronic myelocytic leukemia is described who also developed an abnormality of chromosome #3, i.e., t(3;20)(p21;p13), in blast crisis. This abnormality may be connected with the advent thrombocythemia. The disease was a thrombopenia in the initial phase.