Predominance of chromosome 5 deletions in myeloid neoplasia associated with solid tumors managed by surgical excision.

To assess potential differences in genetic predisposition to myeloid neoplasia, we evaluated the karyotypes and reviewed results of cytogenetic studies on bone marrow specimens from six patients with myelodysplastic syndrome, or acute myeloid leukemia, and a history of solid tumor managed solely by surgical resection. Structural or numerical deletions of chromosome 5 were identified in each of four patients with abnormal marrow karyotypes. Constitutional karyotypes were normal in two patients studied with clonal marrow chromosome abnormalities. Review of previously reported cases of myeloid neoplasia following resection of solid tumors disclosed a preponderance of chromosome 5 deletions. Predisposition to specific chromosome loss may influence genetic expression of disease in solid tumor patients developing hematologic malignancy.

Cytogenetics of bone marrow fibroblastic cells in idiopathic chronic myelofibrosis.

To determine the nature of the fibroblastic proliferation in myelofibrosis, we studied the cytogenetic composition of a pure population of in-vitro bone marrow fibroblastic cells (FC) from a patient with idiopathic chronic myelofibrosis who had trisomy 8 in her unstimulated peripheral blood cells. This cytogenetic abnormality was absent in all the FC studied supporting the premise that in the myeloproliferative disorders the myelofibrosis represents a secondary or non-neoplastic reaction to the clonal proliferation of haematopoietic stem cells.

Mosaicism for ring and isopseudodicentric chromosome 13.

A three-month-old female infant with multiple malformations was noted on routine cytogenetic evaluation to have dicentric/ring mosaicism of chromosome 13. Additional cytogenic investigations indicated that the dicentric could be further defined as an isopseudodicentric. Unlike the double chromosome break in the more common ring 13 cases, the mechanism for isopseudodicentric/ring generation is attributed to chromosome and chromatid breaks with subsequent bridging, breaking and fusion. The phenotypic features are those of a combined duplication-deficiency of chromosome 13.

Balanced reciprocal translocations: risk factors for aneuploid segregant viability.

Reciprocal translocations were studied in two groups of balanced carrier couples: 202 had 210 translocation aneuploid between (LB) infants, and 95 couples had repetitive abortions (AB) without liveborn aneuploids. The observed translocation aneuploidies in the LB group were compared to predicted potential aneuploidies in AB by frequency of chromosome involvement, meiotic segregation mode, and mean trisomic, monosomic and combined genomic imbalances. Qualitative and quantitative differences identified genomic regions and chromosomes possibly vital for in utero survivability. LB aneuploidies indicate non-random chromosome involvement, selection of least detrimental segregants and segments, and predominant transmission from maternal balanced carriers (especially in 3:1 tertiary segregation, 93.5%). For an individual with a balanced reciprocal translocation and untested reproductive capability, an approach is given for predicting whether a translocation aneuploid conceptus will be liveborn or aborted.

Cytogenetic and clinical assessment of six patients with erythroleukemia.

We report the detailed karyotypic analysis and clinical features of six patients with erythroleukemia (EL). Five of six patients studied displayed substantial numeric and structural chromosome abnormalities. The most common alterations in these patients were monosomy for chromosome 7 and 16. All five patients displaying chromosomal abnormalities presented with 100 percent abnormal metaphases in their bone marrow at the time of initial diagnosis. The remaining patient was studied only during remission and had a normal diploid karyotype in all marrow cells analyzed. No patient in this study had either a Ph1 -chromosome (characteristic of CML), or translocations of chromosome #8-#21 (characteristic of AML-M2). Clinically, all but one patient had a brief history; the exception having had polycythemia rubra vera for 18 years prior to the onset of EL. All patients were treated with current Southwest Oncology Group (SWOG) protocols using cytosine arabinoside and anthracycline combinations. Three of five patients entered complete remission. However, remission durations were short (approximately six months) and median survival just over one year. Cytogenetic analysis of three patients in hematologic remission revealed persistence of chromosomal alterations. It is suggested that such remissions be reclassified as partial rather than complete based upon the cytogenetic information.

Balanced translocation karyotypes in patients with repetitive abortion. Case study and literature review.

Cytogenetic studies were conducted upon 100 consecutive couples with abortions. Eight balanced carrier translocation karyotypes were discovered (8%): three cases of Robertsonian translocations and five reciprocal translocations. Two structural variant karyotypes and a poly-X mosaic were also found. A review of the literature on repetitive abortion revealed 82 balanced translocations in 1,331 couples, a rate of 6.2%. Cytogenetic studied should be routine for patients with repetitive abortion. In the pooled series, 3.7% of couples with translocation had wastage, including some with normal offspring; 9.2% had malformed offspring; 62% of the carrier couples lacked the malformation history. Seventy-four percent of the translocations were reciprocal; risk rates for imbalanced progeny were undefined for 90% of the carrier couples. Only 11 imbalanced conceptuses were demonstrated cytogenetically in 262 pregnancies of the carrier group.

Further observations on a 13qXp translocation associated with retinoblastoma.

In a patient with a 13qXp translocation and retinoblastoma the band associated with retinoblastoma (13q14) was clearly translocated intact to the X chromosome rather than being the breakpoint of the translocation. Genetic inactivation of the derivative X chromosome shown by late labeling and cell hybridization techniques in the predominance of cells indicated a functional monosomy for this segment as the most likely predisposing factor in producing retinoblastoma.