Molecular analysis of the genotype-phenotype relationship in factor VII deficiency.

Factor VII (FVII) deficiency is a rare haemorrhagic condition, normally inherited as an autosomal recessive trait, in which clinical presentation is highly variable and correlates poorly with laboratory phenotype. The FVII (F7) gene was sequenced in 48 unrelated individuals with FVII deficiency, yielding a total of 23 novel lesions including 15 missense mutations, 2 micro-deletions, 5 splice junction mutations and a single base-pair substitution in the 5' untranslated region. Family studies were performed in order to distinguish the contributions of individual mutant F7 alleles to the clinical and laboratory phenotypes. Specific missense mutations were evaluated by molecular modelling in the context of the FVIIa-tissue factor crystal structure. Single base-pair substitutions in splice sites and the 5' untranslated region were studied by in vitro splicing assay and luciferase reporter gene assay, respectively. All probands were also typed for four previously reported F7 polymorphisms. In the majority of cases of FVII deficiency studied here, consideration of both mutational and polymorphism data permitted the derivation of plausible explanations for the FVII activity and antigen levels measured in the laboratory. Inter-familial variation in FVII activity and the antigen levels of heterozygous relatives of probands was found to be significantly higher than intra-familial variation, consistent with the view that the nature of the F7 gene lesion(s) segregating in a given family is a prime determinant of laboratory phenotype. Although no relationship could be discerned between laboratory phenotype and polymorphism genotype, the frequencies of the A2 and M2 polymorphic alleles were significantly higher in the FVII-deficient individuals tested than in controls. This suggests that the presence of these alleles may have served to increase the likelihood of pathological F7 gene lesions coming to clinical attention.

Rectal adenocarcinoma in an HIV-infected haemophiliac: case report and review.

Colorectal adenocarcinoma, a relatively uncommon malignancy associated with HIV infection, is now being increasingly recognized. Most reports have been in homosexuals and intravenous drug users and there are no reports of its occurrence in haemophiliacs acquiring HIV via infused factor VIII and without other obvious risk factors or a family history. The present report describes the case of a young heterosexual haemophiliac with HIV infection and no other risk factors who developed rectal carcinoma. The relevant literature is discussed and the clinical importance of recognizing this possible association is emphasized.

Inflammatory bowel disease and refractory anaemia (myelodysplasia).

Two patients with colitis and refractory anaemia requiring multiple transfusions are described. In one the anaemia was detected at the onset of colitis before drug treatment; in the other it started after 21 years of treatment with sulphasalazine and during an exacerbation of colitis with perianal abscess for which he had just been started receiving prednisolone, cofluampicil and metronidazole. Glomerulonephritis developed two weeks after the onset of anaemia. These findings together with a recent report of four patients with Crohn's disease and refractory anaemia suggests that the association may be more than coincidental and may be immune mediated.

Detection of missense mutations by single-strand conformational polymorphism (SSCP) analysis in five dysfunctional variants of coagulation factor VII.

Five unrelated subjects with dysfunctional coagulation factor VII (FVII) were studied in order to identify missense mutations affecting function. Exons 2 to 8 and the intron-exon junctions of their FVII genes were amplified from peripheral white blood cell DNA by PCR and screened by SSCP analysis. DNA fragments showing aberrant mobility were sequenced. The following mutations were identified: in case 1 (FVII:C < 1%, FVII:Ag 18%) a heterozygous A to G transition at nucleotide 8915 in exon 6 results in the amino acid substitution Lys-137 to Glu near the C-terminus of the FVIIa light chain; in case 2 (FVII:C 7%, FVII:Ag 47%) a heterozygous A to G transition at nucleotide 7834 in exon 5 results in the substitution of Gln-100 by Arg in the second EGF-like domain; in case 3 (FVII:C 20%, FVII:Ag 76%) a homozygous G to A transition at nucleotide position 6055 in exon 4 was detected resulting in substitution of Arg-79 by Gln in the first EGF-like domain; in case 5 (FVII:C 10%, FVII:Ag 52%) a heterozygous C to T transition at nucleotide position 6054 in exon 4 also results in the substitution of Arg79, but in this case it is replaced by Trp; case 4 (FVII:C < 1%, FVII:Ag 100%) was homozygous for a previously reported mutation (G to A) at nucleotide position 10715 in exon 8, substituting Gln for Arg at position 304 in the protease domain. Cases 1, 2 and 5 evidently have additional undetected mutations.

Clinical, haematological, and radiological features of children presenting with lymphoblastic mediastinal masses.

During 1968-1978, 68 children presented in six centres in the United Kingdom with lymphoblastic mediastinal masses. The disease was classified as acute lymphoblastic leukaemia (ALL) in 49 children whose bone marrow aspirates contained > 20% lymphoblasts, and as lymphoma (Sternberg lymphosarcoma - LS) in 19 with < 20% marrow infiltration. Male predominated in both groups, and children with ALL had more visceromegaly and lymphadenopathy, lower haemoglobin levels and platelet counts, and higher white cell counts. The most common chest x-ray finding in both groups was a nonspecific anterior mediastinal mass, but the appearances varied considerably and could be classified into three categories, which are illustrated. Pleural effusions were present in 44%. Cell surface-marker studies showed T cell characteristics in 14 of the 17 patients tested. Response to treatment and complications, such as central nervous system (CNS) and testicular relapse, were similar in ALL and LS, and were related to the size of the initial tumour load. Median remission lengths were 37 weeks for ALL and 89 weeks for LS patients. Leukaemic transformation occurred in 47% of LS children. Compared with the outcome in ALL children without mediastinal mass, the results of treatment were poor, regardless of the protocol used, and prophylactic therapy to the CNS reduced the frequency of, but did not eliminate, CNS disease.

Capillary blood collection in haematology.

A capillary blood collection technique which facilitates the estimation of routine haematological parameters, including platelet count and sedimentation rate, is described. The technique requires 0.5 ml of blood, allows closer reproducibility than pipette collection methods, is suitable for monitoring blood counts in patients receiving cytotoxic agents, and can be integrated with semi-and fully-automated production lines.