A chromosomal translocation t(11;14) (p15;q11) is described in a human acute T‐cell leukaemia of immature phenotype (CD3‐, CD4‐, CD8‐). The translocation occurs at a T‐cell receptor joining J delta segment, 12 kb upstream of the constant C delta gene and 98 kb upstream of the C alpha gene at chromosome band 14q11. Nucleotide sequencing shows that both J delta and C delta are very conserved between mouse and man. The region of chromosome 11 involved in the translocation is transcriptionally active and produces a 4‐kb mRNA. The DNA sequence at the chromosome 11 junction shows a perfect match to a recombinase signal sequence implying that this translocation occurred by recombinase error. The occurrence of the translocation breakpoint at the C delta locus, normally rearranged in immature T cells, and the structure of the translocation junctions suggests that the translocation occurred during an attempt at normal rearrangement of the J delta segment in an early thymocyte.

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Objective To analyse the results of the first 2 years of a QF-PCR stand-alone testing strategy for the prenatal diagnosis of aneuploidy in the London region and to determine the advantages and disadvantages of this policy.Methods A review of the results of 9737 prenatal samples received for exclusion of chromosome abnormalities. All samples were subjected to QF-PCR testing for common aneuploidies but only samples fulfilling specific criteria subsequently had a full karyotype analysis. ResultsOf the 9737 samples received, 10.3% had a chromosome abnormality detected by QF-PCR testing. Of the 7284 samples received with no indication for karyotype analysis, 25 (0.3%) received a normal QF-PCR result but subsequently had an abnormal karyotype detected either prenatally as a privately funded test or postnatally. Of these samples, without subsequent abnormal ultrasound findings, five had a chromosome abnormality associated with a poor prognosis, representing 0.069% of samples referred for Down syndrome testing.Conclusion While back-up karyotyping is required for some samples, using QF-PCR as a stand-alone prenatal test for pregnancies without ultrasound abnormalities reduces costs, provides rapid delivery of results, and avoids ambiguous and uncertain karyotype results, reducing parental anxiety.

Eighty-four patients with typical chronic lymphocytic leukemia 27% of patients with B-CLL. [11][12][13] Fegan et al 13 studied 45 (CLL) (by morphological and immunophenotypic criteria) on patients with typical CLL over 5 years and performed cytowhom karyotypes were available were studied. Binet stage at genetic analysis every 6-12 months or more frequently if there diagnosis and follow-up were defined. Survival was calculated was evidence of disease progression. Abnormalities were from diagnosis. Fifty-one percent of patients had a karyotypic detected in 62% at some point during the study with 38% abnormality, the commonest being abnormalities at 13q14 (16%); these patients did not have significantly different surshowing clonal evolution. 11q deletions were found most frevival from patients with normal karyotype. The second comquently in the patients with progressive disease. This original monest abnormality was del(11q) (13%); these patients had sigstudy was extended to an adjacent centre and here we present nificantly worse survival when compared both with patients our updated long-term results. The patients' records were examined and the Binet stage was with CLL have chromosomal abnormalities as detected by noted at diagnosis and any change was documented. Treatcytogenetic analysis 1,2 but few centres perform routine cytogments for CLL were also recorded as were the causes of death. enetic analysis because of the perception that limited prognos-A patient was considered to have had a CLL-related death if tic information can be gained over and above that of the he/she died as a result of cytopenias, high-grade lymphoma Binet/Rai staging. The presence of a clonal abnormality, howor infection; also if CLL was quoted as the cause of death on ever, may be an aid in the diagnosis and assessment of progthe death certificate. Otherwise death was considered nonnosis. Deletions at 13q14 are the most frequent abnormality CLL related. In all cases survival was assessed from diagnosis. in CLL and occur in up to 30% of patients. 2-4 Such patients have been shown to have a similar survival pattern to those with a normal karyotype. 2 Trisomy 12 is another common abnormality, affecting about 20% of patients as determined Diagnosis of CLL by conventional techniques 2 but as many as 30-40% when analysed by FISH, detecting abnormalities in previously norThis required a peripheral lymphocytosis (Ͼ4 × 10 9 /l) of small mal karyotypes. 5,6 Trisomy 12 is thought to be an adverse mature lymphocytes, Ͻ10% prolymphocytes or large lymphoprognostic feature and correlation with atypical morphology cytes and Ͻ15% cleaved or lymphoplasmacytic cells. and poor survival has been shown. 2,6,7 Multiple karyotypic Immunophenotype of typical CLL was needed ie CD5, CD19 abnormalities, a high percentage of abnormal metaphases and and CD23 positive with weak immunoglobulin expression abnormalities of chromosome 14 are also associated with demonstrating or restriction. FMC7 was weak and/or poorer outlook; 2,8-10 at least a proportion of the latter wi...