Search PubMed⌕ Search

Biomedical subjects

E van Loghem

Publications and source records attributed to E van Loghem.

At least 37 records · Page 2Linked to original sources
PubMed1983

Absence of close linkage between Hereditary spherocytosis (SPH) and 24 genetic marker systems including HLA and GM.

A total of 250 individuals belonging to 19 different families, identified through established propositi were simultaneously screened for hereditary spherocytosis (SPH), using stringent criteria, and 27 well-known polymorphic genetic marker systems. The segregation analysis indicated that the pattern of inheritance of SPH in these families, being autosomal and dominant, had a 100% penetrance. A statistical analysis, using the LIPED computer program of Ott (1974), revealed the absence of close linkage between SPH and ABO, ACP1, ADA, AK1, C3, DIA2, ESD, FY, GC, GLO1, GM, GPT1, HLA, HPA, JK, K, KM, MNS, P, PGD, PGM1, PGP, PI, and RH. Since an earlier study by other investigators had convincingly suggested a linkage between SPH and GM, we subjected the data to further analysis and found no significant heterogeneity in our recombination values of linkage between SPH and GM, or any of the other informative loci.

Chromosome Mapping↗
PubMed1983

IgG and IgA heavy chain allotypes in Type 1 diabetes.

IgG and IgA heavy chain allotypes were determined in the sera of 483 Caucasian Type 1 diabetes patients and 503 Caucasian healthy controls. There was no significant difference between patients and controls neither on the level of Gm phenotype frequencies nor on the level of Gm three-locus and two-locus haplotype frequencies. A selective IgA deficiency was found in 14 patients (2.9%) but in none of the control individuals (P less than 10(-4].

Diabetes Mellitus↗
PubMed1983

Selective deficiency of immunoglobulin A2.

A case of familial selective IgA2 deficiency is described. The mother had no detectable IgA2, but a low level of IgA1. She had anti-alpha 2 antibodies of the IgG class. One of her daughters also lacked IgA2 with a normal level of IgA1. The analysis of the immunoglobulin haplotypes of the family suggested the deletion of the alpha 2-gene. In addition, the analysis of B lymphocytes of mother and daughter showed the absence of IgA2-bearing cells. Upon stimulation with pokeweed mitogen, the B cells differentiated into IgA1-containing plasma cells, but IgA2-containing cells were not found. The results suggest a defect in the generation of intraclonal B cell isotype diversity. The molecular basis of this phenomenon is unknown.

Adolescent↗
PubMed1983

Instability of the human immunoglobulin heavy chain constant region locus indicated by different inherited chromosomal deletions.

Previously we reported a gross genetic polymorphism of the human immunoglobulin heavy chain locus manifest by a large internal deletion within the constant region gene segment. We now describe a detailed serological and molecular genetic study of a Tunisian family in which members appear to carry two chromosomes 14 with different DNA deletions. The first is similar to that previously described encompassing three gamma subclass genes, a pseudo-epsilon gene and the alpha 1 subclass gene; the second deletion is less complex involving only the pseudo-epsilon gene and the alpha 1 gene.

Chromosome Deletion↗
PubMed1982

Importance of IgG subclasses of anti-Rh antibodies for the detection of Fc-receptor-bearing human lymphocytes.

13 anti-Rh sera were compared for their usefulness in the detection of Fc-receptor-bearing lymphocytes (EAhum test). IgG subclasses of anti-Rh antibodies were determined by the antiglobulin test with monospecific sera and by the detection of Gm allotypic markers in the haemagglutination inhibition test. Six sera with IgG1 + IgG3 or IgG1 + IgG2 + IgG3 antibodies and one with pure IgG3 antibodies were found to be useful, whereas six other sera with only IgG1 were unsuitable for the EAhum test. G3m markers were detected only on the anti-Rh antibodies which were capable of forming rosettes with lymphocytes. The data show that human peripheral lymphocytes possess Fc receptors for IgG3 immunoglobulins.

Autoantibodies↗
PubMed1982

Human IgG allotypes co-occurring in more than one IgG subclass.

Inheritance of an excess of immunoglobulin allotypes in one haplotype was encountered which could not be explained by the assumption of a duplicated locus. The surplus of allotypes was related to markers on the CH3 domain of gamma 3 chains. Two such cases were investigated extensively. The IgG3 molecules were isolated by gel filtration and by absorption on protein A. Only the usual combination of allotypes appeared to be present on the IgG3 molecules. The supernumerary markers were found in one case on IgG2 molecules and in the other case on IgG1 molecules. This followed from investigations of eluates after separation of the subclasses by immune absorptions. A hypothesis was proposed to explain these events by mutation of a particular position of an otherwise homologous stretch of gamma-subclass DNA.

Chromatography, Affinity↗
PubMed1982

Unusual heavy chains of human IgG immunoglobulins: rearrangements of the ch domain exons.

Unusual combinations--unexpected sets, excess of lack--of antigenic determinants, or Gm allotypes, on the constant regions of the heavy chains of the human IgG1 and IgG3 immunoglobulins are accounted for in terms of genetic events (exchanges, duplications and deletions) involving the DNA sequences, or exons, coding for the three CH1-, CH2- and CH3 domains of the gamma 1 and gamma 3 chains. Equal and unequal cross-overs at the level of the introns without damage to the CH exons are postulated.

Crossing Over, Genetic↗
PubMed1981

The Gm--Pi linkage heterogeneity in view of Pi M subtypes.

In this study linkage between the loci for Gm (gamma-type heavy-chain immunoglobulin markers) and Pi (alpha 1-antitrypsin/alpha 1-protease inhibitor) has been shown in families segregating for the Pi M subtypes (M1, M2, M3 and Msal) as identified by separator isoelectric focusing . The estimate for the Gm--Pi (M type) recombination is 0.29 (95% limits 0.24--0.37) at a peak lod score of 4.31 and with no sex difference. This value is not significantly different from updated recombination frequency estimates for Gm--Pi in Pi MS (0.26) and Pi MZ, SZ and FZ families (0.21). The overall Gm--Pi recombination fraction estimate of 0.26 (95% limits 0.23--0.30) at a peak lod score of 20.75 must now be considered as solid. There is a significant heterogeneity within the male Pi MZ families in that the new Finnish families show a higher recombination between Gm and Pi. There is also a possible segregation distortion (Z:M = 23:8). The heterogeneity is discussed in terms of haplotypes, the behaviour of which could be determined by linked genes or chromosomal rearrangements. The possibility that the alpha 1-antitrypsin level influences recombination frequency has not been ruled out, but cannot explain the heterogeneity within Pi MZ families.

Alleles↗
PubMed1981

Structural studies of a human gamma 3 myeloma protein (Goe) that binds staph protein A.

The partial amino acid sequence of the Fc region of an unusual monoclonal immunoglobulin molecule (Goe), which had the allotypic markers Gm (b0, b3, b5, s, t, v), rarely encountered in Caucasians, was determined. Protein Goe was previously shown to belong to the gamma 3 subclass by antigenic typing, to possess a gamma 3-like hinge region and a gamma 1-like carboxy-terminal octadecapeptide, and to bind to staphylococcal protein A. The sequence of protein Goe resembled that of gamma 3 molecules except for the presence of tyrosine at position 296, alanine at position 339, and histidine and tyrosine at positions 435 and 436. It is of interest that histidine 435 appears to play an important role in binding to Staph protein A. Since tyrosine and phenylalanine at 296 and 300 are typical of G3m(g) molecules, whereas protein Goe is G3m(g-), this may correspond to the non-b1 allotypic marker. Of the numerous explanations to account for these findings, the most likely possibilities are that protein Goe is either a hybrid molecule or the product of a germ line gene representing the G3m s allotype, which is rare in Caucasians and common in Mongoloid populations. Support for the latter alternative is provided by the isolation from normal serum of a small amount of a protein having many of the properties of protein Goe.

Chemical Phenomena↗
PubMed1980

Dystrophia myotonica and myotonia congenita concurring in one family. A clinical and genetic study.

In a unique sibship of 5, 2 siblings were found to have dystrophia myotonica and 3 had myotonia congenita. A study was made of the paternal and maternal families and of the offspring of the 5 siblings. Eighty relatives were examined clinically, by slit-lamp and by electromyography. In the relatives of the mother of the sibship only dystrophia myotonica was found and in the relatives of the father only myotonia congenita. In the offspring of the sibship the two diseases were transmitted independently in the successive generations. All patients showed a clinical picture of either one or the other disease and transitional clinical forms were not found. A linkage study was performed in the family with myotonia congenita and in the family in which both diseases occurred. The myotonia congenita gene is probably not linked to the secretor and lutheran genes. The hypothesis that there is no linkage between myotonia congenita and the secretor-lutheran linkage group was found to be 25 times more probable than the alternative hypothesis that myotonia congenita is linked to this group. This family study therefore provides evidence that dystorphia myotonica and myotonia congenita are both clinically as well as genetically distinct.

Adolescent↗
PubMed1980

A gamma l heavy-chain disease protein *EST) lacking the entire VH and CHl domains.

A gamma l heavy-chain disease protein (EST) is described which lacks the entire VH and CHl domains and starts with the normal sequence of gamma l H-chains corresponding to the beginning of the hinger region (position 216). Although degradation cannot be excluded with certainty, it is probable that this protein is synthesized as an internally deleted gamma heavy-chain disease protein. Presumably a DNA recombination has occurred resulting in the deletion of the genes of coding for the VH and CHl domains with splicing of the precursor RNA to the sequence coding for the hinge region.

Amino Acid Sequence↗
PubMed1980

Immunoglobulin concentration and Gm allotypes in a family with thirty-three cases of myotonic dystrophy.

Serum IgG, IgA, and IgM concentrations were measued in 120 members of a family with 33 cases of Dystrophia myotonica (Dm) and 27 members who were "possibly affected". The Dm individuals had significantly lower serum concentrations of IgG and IgA (P<0.01), while the "possibly affected" did not differ from the matched pair controls. IgG subclass concentrations were measured and GM and Am types determined. The lower concentration of IgA in the affected individuals was not associated with a particular Am type. The concentration of IgG3 was barely lower in the effected than in the controls (P=0.05), but there were no differences for IgG1. When IgG3 concentratin was compared according to Gm haplotype, only the two affected individuals who were Gm gg had a statistically significant lower concentration than the 12 controls (P<0.02). Thus, there is no evidence that a particular subclass of IgG is being hypercatabolized in our Dm patients. A rare Gm haplotype, Gm(-, n, b) had entered the family with two brothers; it is not known whether this codes for an IgG1-IgG3 hybrid molecule or a normal IgG1 molecule with an unknown Gm allele or a gamma 1 deleted Gm haplotype.

Adolescent↗
PubMed1980

Gene deletion and gene duplication within the cluster of human heavy-chain genes. Selective absence of IgG sub-classes.

Individuals with selective absence of IgG1 and IgG2 were discovered by testing for allotypes and isotypes of the respective sub-classes. These individuals were homozygous for sub-class deleted Gm-Am haplotypes, as shown by allotype studies in two families (Gm--;..;g;A2m1/Gm--;n;b;A2m1 and Gm--;n;b;A2m1/Gm--;..;b;A2m1) and by a population study of New Guineans (Gm fa;--;b;A2m2). The individuals with IgG1 sub-class deficiency showed elevation of IgG2, IgG4 and in particular of IgG3. Gene deletion can result from unequal crossing over which renders a complementary chromosome with a duplication of a sub-class gene. In one family, duplication of gamma 3 genes was observed to have happened in one of a twin pair. Quanitation of sub-classes in families with gamma 1- and with gamma 3-duplicated haplotypes did not show increased levels of the gene involved.

Crossing Over, Genetic↗
PubMed1980

Genetically determined deficiencies in IgA and IgG.

Disturbance in the immune response can be caused by malfunction of T and/or B cells. Certain inborn errors such as absence of enzymes in the purine salvage pathway, may lead to severe combined immunodeficiencies or to other syndromes related to impaired immune response, that are mostly diseases of infancy. Selective immunodeficiencies in one or more immunoglobulin subclasses are less severe and occur among adults. The best known is IgA deficiency. The first case of IgG3 subclass deficiency was described in 1976 [13]. Examples of IgG1 and IgG2 deficiencies are reported in this paper. The implication of structural and of regulator genes in the various defects is discussed.

B-Lymphocytes↗
PubMed1979

Gm, Am and Km immunoglobulin allotypes of two populations in Tunisia.

Gm, Am and Km allotypes were investigated in two Tunisian populations (236 samples from Mahdia and 142 samples from Sfax). These populations descend from immigrants and, therefore, the results were compared with those obtained in other populations living in the Near East and in North Africa. The subclass heavy chain allotypes G1m, G2m, G3m and A2m are inherited in fixed combinations. There were five main and four minor Gm-Am haplotypes that could be deduced from the phenotypes. This led to the conclusion that the populations studied are Caucasoids with some African admixture (about 10%) and a very low oriental contribution. Furthermore, there were 11 samples which showed 8 uncommon Gm-Am phenotypes. These could be explained by the assumption of five different uncommon Gm-Am haplotypes. Four of these may have arisen by equal crossing over of prevalent haplotypes. The fifth may be the result of unequal crossing over of prevalent haplotypes. The fifth may be the result of unequal crossing over, since it was proven, by family study, that more markers are transmitted together than are present in the prevalent haplotypes.

Female↗