http://www.stockton-press.co.uk/ejhg deletions was detected, which removed between 1 and 30 exons from the gene. Most microdeletions and insertions occurred at homopolymeric tracts or direct repeats within the coding sequence. These features have not been observed in the other FA gene which has been cloned to date (FAC) and may be indicative of a higher mutation rate in FAA. This would explain why FA group A is much more common than the other complementation groups. The heterogeneity of the mutation spectrum and the frequency of intragenic deletions present a considerable challenge for the molecular diagnosis of FA. A scan of the entire coding sequence of the FAA gene may be required to detect the causative mutations, and scanning protocols will have to include methods which will detect the deletions in compound heterozygotes.

The flow cytometric analysis of leucocytes in whole blood is usually performed on samples in which the erythrocytes have been lysed and the leucocytes fixed. Because lysis and fixation reagents have the potential to introduce artefacts, several commercially available reagents were used to prepare normal and leukaemic lymphocytes for immunophenotypic analysis by flow cytometry, and the results were compared with those obtained from live whole blood. The reagents tested were the ImmunoPrep system and OptiLyse C (Coulter), LF‐1000‐Lyse and Flow (Harlan), Uti‐Lyse (Dako) and FACS Lysing Solution (Becton Dickinson). The effect of each reagent on the apparent expression of CD3, CD5, CD11b, CD45, FMC7, κ and λ antigens was determined on lymphocytes from six normal controls and from six patients with chronic lymphocytic leukaemia (CLL). The following observations were made: (i) the time in minutes for each procedure varied markedly and was 1.5, 15, 20, 30 and 30 for the ImmunoPrep system, OptiLyse C, Uti‐Lyse, FACS Lysing Solution, and LF‐1000, respectively, but only 0.5 min for live whole blood. (ii) The forward and side scatter characteristics were affected by all of the lysis and fixation procedures, and this was most marked for LF‐1000‐Lyse and Flow. (iii) OptiLyse C gave preparations with poor forward and side scatter resolution due to the presence of residual red cell fragments. (iv) Lysis and fixation procedures did not affect the apparent expression of the CD3, CD45, or FMC7 antigens on normal or CLL samples, but gave highly variable results for the expression of the CD5, CD11b, κ, and λ antigens on the CLL samples. We conclude that lysis and fixation procedures can introduce different artefacts in the analysis of normal and leukaemic samples that are best avoided by analysing live whole blood. Cytometry (Comm. Clin. Cytometry) 38: 153–160, 1999.  © 1999 Wiley‐Liss, Inc.

Summary We describe two cases of recurrent autoimmune cytopenias, which were subsequently diagnosed with a 22q11.2 deletion/DiGeorge syndrome. The cases are of particular interest as both possessed limited clinical features of this syndrome, and the investigation of haematological abnormalities led to the establishment of a definitive genetic diagnosis.

Aim-To compare anticardiolipin (ACL) and anti-2 glycoprotein 1 ( 2gp1) enzyme linked immunosorbent assays (ELISAs) in the diagnosis of antiphospholipid syndrome (APS) and to incorporate these results into a meta-analysis of published data. Method-Three representative commercial ACL ELISAs and an in house 2gp1 assay were optimised and then assessed on 124 sera from normal donors, patients with infection, or patients with APS. A Medline search was screened for papers meeting defined criteria to conduct a meta-analysis. The performance of the assays used in this study was included. Results-A non-quantitative ACL assay performed at least as well as the anti2gp1 assay in the diagnosis of APS. Meta-analysis confirmed that neither assay is perfect, although the anti-2gp1 assay had a higher specificity and lower sensitivity than the ACL assay. Conclusions-The pooled data suggest that the ACL assay is used to investigate thrombosis without overt underlying pathology and that the improved specificity of the anti-2gp1 assay is exploited where infection, connective tissue disease, or atheroma are present. (J Clin Pathol 2001;54:693-698)

We describe a 28-year-old male patient who presented with apparently de novo acute myeloid leukaemia (AML) who was subsequently found to have Fanconi's anaemia (FA). The gene for complementation group A (FAA) has recently been localized to chromosome 16q24.3 and utilizing genetic markers closely linked to this locus we were able to conclude that this patient was likely to belong to complementation group A. FA presenting as AML is an exceptionally rare event and all previously described cases have occurred in patients less than 21 years of age. We conclude that the diagnosis of FA should always be considered in younger patients presenting with AML. It is important that the correct diagnosis is made in these individuals because the administration of conventional chemotherapy may well have devastating consequences for them. Correlations between the specific mutations causing FA and clinical phenotypes are likely to become apparent as more genetic analyses are performed in this group of patients.