New variant of type II von Willebrand's disease with structural abnormality of plasma von Willebrand factor in a patient with very mild bleeding history.

A new variant of von Willebrand's disease has been discovered in 2 members of a Macedonian family of 6. The proband, an 8-year-old boy, showed a prolonged bleeding episode on 1 occasion. Ristocetin-induced platelet aggregation and bleeding time were normal. In plasma, ristocetin cofactor activity (RCo) and von Willebrand factor (vWf) antigen were reduced to the same clearly low level. The determination of vWf antigen of platelets resulted in borderline values, while RCo was clearly reduced. Low- and intermediate-resolution agarose gel electrophoresis showed absence of the largest multimers in plasma vWf, and slight reduction in platelet vWf. High-resolution gels revealed abnormal multimeric structure only in plasma vWf. The smaller multimers could be resolved in a broad central band flanked by 4 fainter satellite bands; however, satellite bands close to the central band were more intense, and more distant ones were fainter, compared to normal plasma. The central band of the fastest-moving multimer was markedly intensified, and the mobility of the whole quintuplet was slightly reduced. Heredity seems to be autosomal-dominant. No mutation was found in exon 28 of the vWf gene. Because there was only 1 mild bleeding episode in the family, this structural variation seems to have only little clinical consequence. We conclude that this vWf abnormality is different from those observed in other type II variants previously described. Based on the revised classification by the International Society on Thrombosis and Haemostasis, we proposed designation type 2A-Bern for this new subtype.

Multimeric analysis of von Willebrand factor by vertical sodium dodecyl sulphate agarose gel electrophoresis, vacuum blotting technology and sensitive visualization by alkaline phosphatase anti-alkaline phosphatase complex.

To detect von Willebrand factor multimers in plasma samples and factor VIII concentrates, a vertical discontinuous SDS electrophoresis was developed. A vacuum blotting system allowed to improve the transfer to the nitrocellulose membrane. The visualization of the separated multimers was sensitized by applying an alkaline phosphatase anti-alkaline phosphatase staining technique. The reported method clearly shows structural abnormalities of von Willebrand factor and deficiency of high multimers, the vacuum transfer is efficient and the sensitivity of the staining system is very high.

Thromboembolism and bleeding tendency in congenital factor XII deficiency--a study on 74 subjects from 14 Swiss families.

In order to assess the clinical implications of hereditary F XII deficiency, all available members of Swiss families with F XII deficiency were investigated. Based on the F XII:C values and the family pedigree, the 74 subjects, aged 8-82 years, were classified as homozygotes/double heterozygotes for F XII deficiency (n = 18), as obligatory (n = 20) or possibly (n = 25) heterozygotes, respectively, and as normals (n = 11). None of the 18 subjects with F XII:C less than 0.01 U/ml and only one possibly heterozygous woman had an abnormal bleeding tendency, confirming the notion that Hageman trait generally does not result in a hemorrhagic diathesis. Two of the 18 subjects with severe F XII deficiency had suffered from venous thromboembolic disease at age less than 40 years. One heterozygous woman had a leg ulcer probably due to venous thrombosis. Thus, whereas homozygous F XII deficiency may be associated with an increased risk for venous thromboembolic disease, partial F XII deficiency is not, by itself, a strong risk factor for thrombosis. Whereas 17 of the 18 subjects with F XII:C less than 0.01 U/ml had no detectable F XII:Ag, one cross reacting material-positive F XII deficient subject (F XII:Ag = 0.11 U/ml) was identified. The dysfunctional F XII, present in this subject's plasma and tentatively called F XII Bern, is the fourth abnormal F XII molecule identified so far.

Study of five haemogenetic markers (Gc, C3, Bf, Ag, and GALT) in six Indonesian populations and in 12 subgroups of Balinese.

In various ethnic groups of the Indonesian archipelago and of Bali, the polymorphisms of the serum proteins Gc globulin (vitamin D-binding protein), C3 (complement component 3), Bf (complement factor B), Ag x,y (lipoprotein allotypes), and of the red cell enzyme system GALT (galactose-1P-uridyltransferase) were analysed. Among the studied proteins, the Gc system was the most informative one for the anthropologist. Besides considerable differences of frequencies of the common alleles Gc*1F, Gc*1S and Gc*2, a number of rare alleles (1A1, 1A3, 1A8, 1A9, 1A12, 1C2, 1C21, 1C24, and 2C8) and some new ones (1C28, 1C29, 1C30, 2C9) were observed. The presence of Gc*1A1 demonstrates the relationship to the Australo-Melanesian populations, but Mongolian variants (1A3, 1A8, 1A9, 1C2) were also encountered. Within the C3 system a very high frequency of the C3*S allele was observed in all populations. The rare alleles C3*F0.55, C3S1, and C3*S0.5 were observed in some groups. A new allele (C3*F0.35) was detected in a Chinese individual and in a nobleman from Bali. The frequency of the Bf*F allele was rather low in general, and the Bf*S0.7 allele was found in three Indonesian individuals only. The Ag*(x) frequencies were rather high, as it is known for Asiatic populations. Variability among subgroups was not very pronounced. The GALT*2 allele (Duarte variant of the enzyme) was observed very rarely; however, it was present in several populations. Enzyme activities could not be determined, and therefore we cannot tell whether the galactosaemia gene (GALT*0) was present or not.

FPA content - a criterion of quality for plasma as factor VIII source.

The appearance of fibrinopeptide A (FPA) in plasma indicates that factor VIII has been at least partially activated; consequently, we asked the following questions: (1) Is the FPA content of single donor plasma influenced by the method of blood collection? (2) Does a high FPA content of the starting fresh frozen plasma impair the quality of factor VIII preparations? Using a modified procedure adapted to the assay of large series of samples, we surveyed the FPA content of normal donor plasma. Our results show that the FPA content of donor plasma depends strongly on the quality of blood collection. Improved mixing of the anticoagulant with the blood led to a drastic reduction of the FPA content of the plasma. Furthermore, two lots of factor VIII concentrates produced from FPA-poor plasma showed significant improvement in stability and solubility.

Genetic polymorphism of glycine-rich beta-glycoprotein in the Italian population.

Genetic polymorphism of glycine-rich beta-glycoprotein (GBG) was studied in populations from northern and southern Italy, respectively. Gene frequencies were as follows: northern Italy (n = 431): GbS = 0.7675, GbF = 0.2049, GbS 0.7 = 0.0127, GbF1 = 0.0139; southern Italy (n = 161): GbS = 0.7050, GbF = 0.2360, GbS 0.7 = 0.0373, GbF1 = 0.0217. Comparison of these two populations with the Swiss population revealed a significant drift in gene frequencies from north to south. A new GBG phenotype, supposedly heterozygous, with a slow migrating F band and a regular S band in agarose electrophoresis was observed.

Isoelectric focusing of human red cell phosphoglucomutase (PGM1): phenotype distribution in the Swiss population - rare phenotypes.

Gene frequencies of PGM1 phenotypes as obtained by isoelectric focusing on polyacrylamide gel in the pH range from 4 to 8 were determined in 501 samples of Swiss blood donors. Results were in good agreement with the expected distribution according to the Hardy-Weinberg law. Frequencies were PGM1a1 = 0.6278, PGM1a2 = 0.1936, PGM1a3 = 0.1297, PGM1a4 = 0.0489. Comparison with other data of the white population showed no significant differences. Isoelectric points of regular and rare gene products were determined. Application of the method in routine paternity testing is discussed.

A new rare phenotype of glycine-rich beta-glycoprotein.

A rare phenotype of serum glycine-rich beta-glycoprotein was found in a healthy Swiss woman. The rare gene product was also observed in three of her four sons.

Variable degradation of factor VIII-related protein in lyophilised concentrates of antihaemophilic factor (AHF).

Factor VIII-related properties (coagulant = VIII : C, 'Willebrand' factor = VIII R : WF, antigen = VIII R : AG) are measured in a constant proportion in normal plasma and certain preparations of highly purified factor VIII (relative ratios: 0.5--1.5). We tested these activities in some commercial, lyophilised concentrates of factor VIII and found a variable increase of the ratio VIII R : AG/VIII R : WF. The relative increase of VIII R : AG, and/or loss of VIII R : WF, was attributed to variable degradation of factor VIII-related protein(s) which was directly visualized by electrophoresis on 2.75% polyacrylamide gels in the presence of sodium dodecyl sulphate.

Naturally occurring human antibodies with specificity for light chains of immunoglobulins.

Human sera of different categories were screened for antibodies against IgA. A surprisingly high incidence of antibodies was observed. All of these antibodies were of restricted specificity, i.e. able to react with one or a few individual IgAs from a panel of eight myeloma proteins used in the screening. In one serum of a patient with selective IgA deficiency an antibody against the allotype A2m(1) was found. Some of the antibodies were shown to belong to the IgG class. The IgA, IgG and IgM content of the antibody-containing sera was generally increased. Two different antibodies which both reacted with the same individual IgA were studied in detail. The antigen involved could not be detected in normal Caucasian sera but was detectable in some sera of patients with IgA, IgG, IgM or IgD paraproteinemia. The antigenic site was located on the light chain of the Ig molecule but no correlation with either the light chain type or the genetically determined Inv factor was evident.

A new genetic variant of galactose-1-phosphate uridyl transferase.

The enzyme galactose-1-phosphate uridyl transferase (E.C.2.7.7.12), which has an important function in the metabolism of galactose, exists in multiple molecular forms. The different phenotypes are genetically determined. They can be distinguished according to their electrophoretic mobility. The enzymatic activity of the different gene products varies within certain limits. A new phenotype of the enzyme has been detected in the red cells of a healthy individual. The electrophoretic migration of this phenotype is slower compared to the wild type and its enzymatic activity is lower, but still sufficient as not to cause galactosemia. An extensive family study revealed that the rare gene is inherited according to mendelian law. Independently the same gene product has been detected in two other, nonrelated individuals out of a total of 1668 samples tested. The gene frequency can therefore be estimated to 0.0009 in the Swiss population. We suggest that the new type be called Berne variant of galactose-1-phosphate uridyl transferase.