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Volker Schuster

Publications and source records attributed to Volker Schuster.

At least 19 recordsLinked to original sources
PubMed2006

Simultaneous manifestation of fulminant infectious mononucleosis with haemophagocytic syndrome and B-cell lymphoma in X-linked lymphoproliferative disease.

X-linked lymphoproliferative disease is a rare T and NK cell immune deficiency which most frequently presents as fulminant infectious mononucleosis following infection with the Epstein-Barr virus (EBV). We report the case of a 4-year-old boy from a Spanish family presenting with severe infectious mononucleosis. In the course of the disease he developed hepatic failure, pancytopenia and neurologic impairment, leading to death after less than 2 months. The results of bone marrow biopsy and autopsy indicated a histological diagnosis of both high-grade B-cell lymphoma and virus-associated haemophagocytic syndrome, thereby confirming the simultaneous presence of two different manifestations of X-linked lymphoproliferative disease (XLP) in this patient. The family history revealed four close male relatives dying under similar circumstances, one of whom died following a vaccination against measles. Molecular genetic studies identified a novel mutation in the SH2D1A gene in several members of the family, establishing the diagnosis of XLP. Fatal EBV infection in male infants is highly indicative of XLP. Virus-associated haemophagocytic syndrome and B-cell lymphoma can occur concomitantly and may be difficult to distinguish due to their similar histological pictures.

Child, Preschool↗
PubMed2006

Molecular and clinical spectrum of type I plasminogen deficiency: A series of 50 patients.

Severe type I plasminogen (PLG) deficiency has been causally linked to a rare chronic inflammatory disease of the mucous membranes that may be life threatening. Here we report clinical manifestations, PLG plasma levels, and molecular genetic status of the PLG gene of 50 patients. The most common clinical manifestations among these patients were ligneous conjunctivitis (80%) and ligneous gingivitis (34%), followed by less common manifestations such as ligneous vaginitis (8%), and involvement of the respiratory tract (16%), the ears (14%), or the gastrointestinal tract (2%). Four patients showed congenital occlusive hydrocephalus, 2 with Dandy-Walker malformation of cerebellum. Venous thrombosis was not observed. In all patients, plasma PLG levels were markedly reduced. In 38 patients, distinct mutations in the PLG gene were identified. The most common genetic alteration was a K19E mutation found in 34% of patients. Transient in vitro expression of PLG mutants R134K, delK212, R216H, P285T, P285A, T319_N320insN, and R776H in transfected COS-7 cells revealed significantly impaired secretion and increased degradation of PLG. These results demonstrate impaired secretion of mutant PLG proteins as a common molecular pathomechanism in type I PLG deficiency.

Animals↗
PubMed2006

A missense mutation in the ZFHX1B gene associated with an atypical Mowat-Wilson syndrome phenotype.

Mowat-Wilson syndrome (MWS) is a rare mental retardation-multiple congenital anomalies syndrome associated with typical facial dysmorphism. Patients can show a variety of other anomalies like short stature, microcephaly, Hirschsprung disease, malformations of the brain, seizures, congenital heart defects and urogenital anomalies. Mutations leading to haploinsufficiency of the ZFHX1B gene have been described as the underlying cause of this condition. We report on the clinical findings in a 2(1/2)-year-old boy with some aspects out of the MWS-spectrum in addition to unusual anomalies and a novel missense mutation in the ZFHX1B gene.

Abnormalities, Multiple↗
PubMed2005

Unusual presentation of congenital disorder of glycosylation type 1a: congenital persistent thrombocytopenia, hypertrophic cardiomyopathy and hydrops-like aspect due to marked peripheral oedema.

UNLABELLED: Of the congenital disorder of glycosylation (CDG) syndromes, type 1a is the most common. CDG 1a is a multisystem disorder with a wide clinical spectrum. We report on a term newborn with a severe and fatal clinical course of CDG 1a syndrome. Skin fibroblasts showed a reduced activity of phosphomannomutase 2 (PMM2) and mutation analysis revealed a compound heterozygous PMM2gene mutation (F119L/F157S). Presenting features at birth were hypertrophic non-obstructive cardiomyopathy, "orange-peel" skin, inverted nipples and a hydrops-like aspect due to marked peripheral oedema. Suspected hydrops fetalis was not confirmed due to lack of ascites and pleural effusions. Striking clinical problems were therapy-resistant arterial hypertension, recurrent pericardial and pleural effusions and feeding difficulties with failure to thrive. Persistent congenital thrombocytopenia and hyperferritinaemia in the absence of infection were noted. Bone marrow cytology revealed a macrophage activation of unknown aetiology. CONCLUSION: Congenital thrombocytopenia, unspecific macrophage activation and a hydrops-like aspect without a real hydrops fetalis broaden the already wide phenotypic spectrum of congenital disorder of glycosylation syndrome type 1a.

Cardiomyopathy, Hypertrophic↗
PubMed2004

Ligneous (pseudomembranous) inflammation involving the female genital tract associated with type-1 plasminogen deficiency.

Ligneous (pseudomembranous) inflammation of the female genital tract is a rare and unusual condition characterized by extensive subepithelial fibrin deposition and associated inflammation. Ligneous inflammation in extragenital sites, predominantly the conjunctiva, has been linked to plasminogen deficiency. Individuals with plasminogen deficiency are unable to remove fibrin deposited in injured mucosal tissue. Severe systemic ligneous inflammation involving the female genital tract that is linked to hypoplasminogenemia has not previously been described. We present a patient with ligneous inflammation of her genital, middle ear, and oral mucosa that was associated with type-1 homozygous plasminogen deficiency due to a novel missense mutation in the plasminogen gene.

DNA↗
PubMed2004

Characterization of plasminogen variants in healthy subjects and plasminogen mutants in patients with inherited plasminogen deficiency by isoelectric focusing gel electrophoresis.

Plasmin(ogen) plays an important role in fibrinolysis and wound healing. Severe hypoplasminogenemia has recently been linked to ligneous conjunctivitis. Plasminogen (plg) is known as a polymorphic protein and most of these variants have been identified using isoelectric focusing (IEF) gel electrophoresis. Here, we studied common plg variants from healthy subjects and plg mutants from three patients with hypoplasminogenemia and three subjects with dysplasminogenemia by molecular genetic analysis and IEF. Analysis of 24 healthy subjects showed that subjects with the most common IEF plg phenotype A (n=12) were homozygous for aspartate at position 453 (453D), while both subjects with IEF plg phenotype B were homozygous for asparagine at this position (453N). Subjects with IEF plg phenotype AB (n=10) were compound-heterozygous for 453D/453N. Three patients with severe hypoplasminogenemia and different plg gene mutations exhibited characteristic "abnormal" IEF band patterns when compared with IEF plg phenotypes A and B. In all heterozygous family members the observed IEF plg phenotype was derived from the wild type plg molecule only, probably due to low concentration of the mutant plg molecule in plasma. In contrast, in three unrelated subjects with heterozygous dysplasminogenemia an equal "mixture" of wild type and mutant plg was found by IEF analysis. In conclusion, plg phenotyping by IEF in combination with molecular analysis of the plg gene seems to be a useful method for characterization of plg variants and mutants.

Asparagine↗
PubMed2003

Ligneous conjunctivitis, hydrocephalus, hydrocele, and pulmonary involvement in a child with homozygous type I plasminogen deficiency.

UNLABELLED: Ligneous conjunctivitis is a rare and unusual form of chronic pseudomembranous conjunctivitis which usually starts in early infancy. Plasminogen deficiency has recently been associated with ligneous conjunctivitis. The disease may be associated with pseudomembranous lesions of other mucous membranes in the mouth, nasopharynx, trachea, and female genital tract and also with congenital hydrocephalus. In this report, a 1-month-old Turkish boy who had pseudomembranous conjunctivitis, occlusive hydrocephalus, and hydrocele is presented. After surgery for ventriculo-peritoneal shunt establishment, he developed inspiratory stridor, respiratory distress, and pulmonary atelectasis. Tracheal pseudomembranes were also demonstrated by bronchoscopy. Plasminogen antigen level and plasminogen activity were very low. Genomic DNA from the patient was screened for mutations in the plasminogen gene and a homozygous L650fsX652 mutation (deletion of 2081C) was detected. Both of his parents were heterozygous for this mutation. He died due to respiratory failure during follow-up. CONCLUSION: Ligneous conjunctivitis related to type I plasminogen deficiency is relatively common in the Turkish population, however, mutations are heterogeneous and a common founder is unlikely.

Chromosome Deletion↗
PubMed2003

Mutation spectrum of human SLC39A4 in a panel of patients with acrodermatitis enteropathica.

Acrodermatitis enteropathica is rare autosomal recessive disorder characterized by a severe nutritional zinc deficiency. We and others have recently identified the human gene encoding an intestinal zinc transporter of the ZIP family, SLC39A4, as the mutated gene in acrodermatitis enteropathica (AE). A first mutation screening in 8 AE families (15 patients out of 36 individuals) revealed the presence of six different mutations described elsewhere. Based on these results, we have evaluated the involvement of SLC39A4 in 14 patients of 12 additional AE pedigees coming either from France, Tunisia, Austria or Lithuania. A total of 7 SLC39A4 mutations were identified (1 deletion, 2 nonsense, 2 missense, and 2 modifications of splice site), of which 4 are novel: a homozygous nonsense mutation in 3 consanguineous Tunisian families [c.143T>G (p.Leu48X)], a heterozygous nonsense mutation (c.1203G>A (p.Trp401X)) in a compound heterozygote from Austria also exhibiting an already known missense mutation, and distinct homozygous mutations in families from France or Tunisia [c.475-2A>G and c.184T>C (p.Cys62Arg)]. Furthermore, two other potential mutations [c.850G>A (p.Glu284Lys) and c.193-113T>C] were also observed at homozygous state in a French family formerly described. This study brings to 21 the number of reported SLC39A4 mutations in AE families.

Acrodermatitis↗
PubMed2003

A K19E missense mutation in the plasminogen gene is a common cause of familial hypoplasminogenaemia.

The prevalence of familial plasminogen deficiency in Scotland has recently been calculated at 2.9/1000. However, little is known of the molecular genetic background and the frequency of plasminogen gene mutations in most cases of inherited plasminogen deficiency. Having previously identified 28 unrelated subjects with familial plasminogen deficiency from a cohort of 9611 blood donors, we have now reviewed 19 of these 28 subjects and screened the plasminogen gene in 15 subjects with hypoplasminogenaemia (plus five relatives) and four subjects with dysplasminogenaemia for mutations and polymorphisms. A missense mutation K19E in the plasminogen gene was found in 13 of the 15 propositi with hypoplasminogenaemia, in one of these in a homozygous manner. In two subjects with hypoplasminogenaemia, two new mutations (P353A and R471X) were identified. These three different mutations, if inherited in a homozygous or compound-heterozygous manner, may be associated with the development of ligneous conjunctivitis. In four subjects with dysplasminogenaemia, three heterozygous mutations (C548G, n = 1; A601T, n = 1; G693R, n = 2) were found. None of the propositi with plasminogen deficiency developed venous thrombosis at any time. In conclusion, the K19E mutation in the plasminogen gene is a common cause of hypoplasminogenaemia in Scotland, with an estimated prevalence of around 0.14%.

Amino Acid Sequence↗
PubMed2002

Unimpaired activation of c-Jun NH2-terminal kinase (JNK) 1 upon CD40 stimulation in B cells of patients with X-linked agammaglobulinemia.

X-linked agammaglobulinemia (XLA) is caused by mutations in the gene encoding the cytoplasmic Bruton's tyrosine kinase (Btk). Btk has been shown to play an essential role in the development of B1 (CD5+) and conventional circulating mature B cells (B2) in mouse and man. It has been shown in earlier studies that Btk is involved in both the BCR- and CD40-mediated signaling pathways. In this study, we analyzed the responsiveness of Epstein-Barr virus (EBV) transformed B cells from nine XLA patients to CD40 stimulation, particularly the CD40 induced activation of c-Jun N-terminal kinase (JNK). In eight XLA patients the JNK activation was unimpaired and in one case INK could not be activated by anti-CD40 stimulation. Btk protein expression was detectable by Western blotting in six cases, in one case Btk expression was drastically reduced, and in three cases no Btk expression could be observed. Btk kinase activity was found in three cases and it was reduced in one and not detectable in five cases. Furthermore, in one female patient with an agammaglobulinemia, Btk expression and function as well as JNK activation by CD40 stimulation was unimpaired. Our findings demonstrate that INK activation via the CD40 signaling pathway is intact in EBV-transformed B cells of most if not all XLA patients, independent of the mutation and its effect on Btk expression and kinase activity. We suggest that Btk is not necessary for the activation of INK upon CD40 stimulation, at least in the B cell subpopulation we had studied. We cannot exclude that these B cells belong to a "leaky" B-cell subpopulation in which the CD40 signaling pathway has become independent of Btk function.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed2002

Bruton's tyrosine kinase is activated upon CD40 stimulation in human B lymphocytes.

Bruton's tyrosine kinase (Btk) is known to be involved in a broad array of signal transduction pathways necessary for the proliferation, survival and development of B cells. Mutations in the Btk gene are causually linked to the development of X-linked agammaglobulinemia (XLA) in humans. We show here, that CD40 ligation leads to tyrosine phosphorylation of Btk in the human immature B cell line MHH-PREB-1. Even though the CD40-mediated tyrosine phosphorylation of Btk is less efficient than that mediated through the B cell receptor, CD40 stimulation results in a marked and continous activation of Btk in MHH-PREB-1 cells and, to a lesser extent, in a transient Btk activation in Daudi cells. Furthermore, in Daudi cells we observed that tyrosine phosphorylation and activation of Btk is correlated with its translocation from the cytosolic to the membraneous fraction. These data suggest that, in addition to the BCR, CD40 is a surface receptor through which the activity of Btk can be stimulated in human B cells.

Agammaglobulinaemia Tyrosine Kinase↗