Winnie Schröder

Factor V Leiden, Prothrombin Gene G20210A Variant, and Methylenetetrahydrofolate Reductase C677T Genotype in Young Adults With Ischemic Stroke

Ischemic stroke in young adults is a well-known disease, but despite extensive clinical and laboratory investigations, its etiology remains unclear in approximately half of the cases. We examined the prevalence of factor V Leiden, the prothrombin G20210A genotype, and the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene in 100 patients (51 males and 49 females) who survived an ischemic stroke without a cardiac embolic source at an age ≤45 years, and in 238 healthy control subjects from the same geographic area. The patients were selected for study only if the diagnosis of stroke was documented by computed tomography scan or nuclear magnetic resonance (NMR) of the brain, or both. Heterozygosity for the FV Leiden mutation was found in 3 patients (3.0%) and in 10 control subjects (4.2%). Two patients (2.0%) and five control subjects (2.1%) were heterozygous for the prothrombin G20210A mutation. The frequencies of the MTHFR 677TT, CT, and CC genotypes in the patient group were 12%, 37%, and 51%, respectively, and were not significantly different from those in control subjects (11%, 40%, and 49%, respectively). In conclusion, our results indicate that FV Leiden mutation, prothrombin G20210A genotype, and homozygosity for the C677T mutation in the MTHFR gene are not associated with an increased risk for ischemic stroke in young adults.

High mutation detection rates in cerebral cavernous malformation upon stringent inclusion criteria: one-third of probands are minors.

Cerebral cavernous malformations (CCM) are prevalent vascular malformations occurring in familial autosomal dominantly inherited or isolated forms. Once CCM are diagnosed by magnetic resonance imaging, the indication for genetic testing requires either a positive family history of cavernous lesions or clinical symptoms such as chronic headaches, epilepsy, neurological deficits, and hemorrhagic stroke or the occurrence of multiple lesions in an isolated case. Following these inclusion criteria, the mutation detection rates in a consecutive series of 105 probands were 87% for familial and 57% for isolated cases. Thirty‐one novel mutations were identified with a slight shift towards proportionally more CCM3 mutations carriers than previously published (CCM1: 60%, CCM2: 18%, CCM3: 22%). In‐frame deletions and exonic missense variants requiring functional analyses to establish their pathogenicity were rare: An in‐frame deletion within the C‐terminal FERM domain of CCM1 resulted in decreased protein expression and impaired binding to the transmembrane protein heart of glass (HEG1). Notably, 20% of index cases carrying a CCM mutation were below age 10 and 33% below age 18 when referred for genetic testing. Since fulminant disease courses during the first years of life were observed in CCM1 and CCM3 mutation carriers, predictive testing of minor siblings became an issue.

New ZMPSTE24 (FACE1) mutations in patients affected with restrictive dermopathy or related progeroid syndromes and mutation update

Restrictive dermopathy (RD) is a rare and extremely severe congenital genodermatosis, characterized by a tight rigid skin with erosions at flexure sites, multiple joint contractures, low bone density and pulmonary insufficiency generally leading to death in the perinatal period. RD is caused in most patients by compound heterozygous or homozygous ZMPSTE24 null mutations. This gene encodes a metalloprotease specifically involved in lamin A post-translational processing. Here, we report a total of 16 families for whom diagnosis and molecular defects were clearly established. Among them, we report seven new ZMPSTE24 mutations, identified in classical RD or Mandibulo-acral dysplasia (MAD) affected patients. We also report nine families with one or two affected children carrying the common, homozygous thymine insertion in exon 9 and demonstrate the lack of a founder effect. In addition, we describe several new ZMPSTE24 variants identified in unaffected controls or in patients affected with non-classical progeroid syndromes. In addition, this mutation update includes a comprehensive search of the literature on previously described ZMPSTE24 mutations and associated phenotypes. Our comprehensive analysis of the molecular pathology supported the general rule: complete loss-of-function of ZMPSTE24 leads to RD, whereas other less severe phenotypes are associated with at least one haploinsufficient allele.

Structural gene aberrations in mucopolysaccharidosis II (Hunter)

SummaryA total of 14 unrelated German patients with X-linked iduronate-2-sulfatase (IDS) deficiency (Hunter syndrome, MPS II) showing variable clinical manifestations was screened for structural gene aberrations by Southern analysis. Using the IDS cDNA clone c2S15 as a probe, no Southern fragments could be detected in blots in the severely affected patient G-65 with respect to DNA digested by HindIII, PstI and TaqI, suggesting a total loss of the IDS structural gene. In this patient, the flanking loci DXS 297, DXS 296 and DXS 466 were tested. The locus DXS 466 is involved in the deletion, whereas both of the other loci are present. A normal 9.0-kb fragment disappeared and an aberrant fragment of 3.5 kb occurred in the HindIII blot of patient G-117. A normal Southern pattern was found in PstI and TaqI blots of this patient. This result can be interpreted as the generation of an additional HindIII restriction site by point mutation in an IDS gene intron.

A new marker at DXS 115 useful for carrier detection in hemophilia A

SummaryIn this brief communication we report a new intergenic polymorphism at DXS115 as a marker for detection of heterozygotes in families at risk for hemophilia A. Total genomic DNA was isolated from white blood cells, double digested by KpnI and XbaI and hybridized with EcoRI/SstI fragment of the genomic probe p482.6. The incidence of the polymorphic 5.1-kb fragment was estimated as 0.069 in a German population. A technical advantage of using the XbaI/KpnI RFLP is that both the intragenic XbaI-RFLP in intron 22 of factor VIII gene and the new intergenic RFLP can be evaluated at the same time.

Evidence Supporting Tight Linkage of X-Linked Emery-Dreifuss Muscular Dystrophy to the Factor VIII: C Gene

In a large German family with Emery-Dreifuss muscular dystrophy (EDMD) linkage analysis was performed using the factor IX gene (F9), the factor VIII:C gene (F8), the anonymous DNA probe DXS52, and DXS15 as markers. Tight linkage was found between the EDMD locus and the F8 probe (Zmax = 1.19; theta max = 0.00), DXS15 (Zmax = 1.75; theta max = 0.00) and DXS52 (Zmax = 2.26; theta max = 0.00). Weak linkage was found to F9 (Zmax = 0.02; theta max = 0.43). The data from the literature and our results suggest that the gene locus of EDMD is close to F8 (confidence interval theta = 0-0.07). The new linkage data are useful for carrier detection and diagnosis of EDMD patients before onset of major clinical signs.

Diagnostic single gene analyses beyond Sanger

Molecular testing of congenital coagulation and platelet disorders offers confirmation of clinical diagnoses, supports genetic counselling, and enables predictive and prenatal diagnosis. In some cases, genotype-phenotype correlations are important for predicting the clinical course of the disease and adaptation of individualized therapy. Until recently, genotyping has been mainly performed by Sanger sequencing. While next generation sequencing (NGS) enables the parallel analysis of multiple genes, the cost-value ratio of custom-made panels can be unfavorable for analyses of specific small genes. The aim of this study was to transfer genotyping of small genes involved in congenital coagulation and platelet disorders from Sanger sequencing to an NGS-based method. A LR-PCR approach for target enrichment of the entire genomic regions of the genes F7, F10, F11, F12, GATA1, MYH9, TUBB1 and WAS was combined with high-throughput sequencing on a MiSeq platform. NGS detected all variants that had previously been identified by Sanger sequencing. Our results demonstrate that this approach is an accurate and flexible tool for molecular genetic diagnostics of single small genes.Molecular testing of congenital coagulation and platelet disorders offers confirmation of clinical diagnoses, supports genetic counselling, and enables predictive and prenatal diagnosis. In some cases, genotype-phenotype correlations are important for predicting the clinical course of the disease and adaptation of individualized therapy. Until recently, genotyping has been mainly performed by Sanger sequencing. While next generation sequencing (NGS) enables the parallel analysis of multiple genes, the cost-value ratio of custom-made panels can be unfavorable for analyses of specific small genes. The aim of this study was to transfer genotyping of small genes involved in congenital coagulation and platelet disorders from Sanger sequencing to an NGS-based method. A LR-PCR approach for target enrichment of the entire genomic regions of the genes F7, F10, F11, F12, GATA1, MYH9, TUBB1 and WAS was combined with high-throughput sequencing on a MiSeq platform. NGS detected all variants that had previously been identified by Sanger sequencing. Our results demonstrate that this approach is an accurate and flexible tool for molecular genetic diagnostics of single small genes.Molecular testing of congenital coagulation and platelet disorders offers confirmation of clinical diagnoses, supports genetic counselling, and enables predictive and prenatal diagnosis. In some cases, genotype-phenotype correlations are important for predicting the clinical course of the disease and adaptation of individualized therapy. Until recently, genotyping has been mainly performed by Sanger sequencing. While next generation sequencing (NGS) enables the parallel analysis of multiple genes, the cost-value ratio of custom-made panels can be unfavorable for analyses of specific small genes. The aim of this study was to transfer genotyping of small genes involved in congenital coagulation and platelet disorders from Sanger sequencing to an NGS-based method. A LR-PCR approach for target enrichment of the entire genomic regions of the genes F7, F10, F11, F12, GATA1, MYH9, TUBB1 and WAS was combined with high-throughput sequencing on a MiSeq platform. NGS detected all variants that had previously been identified by Sanger sequencing. Our results demonstrate that this approach is an accurate and flexible tool for molecular genetic diagnostics of single small genes.

Diagnostic single gene analyses beyond Sanger: Economic high-throughput sequencing of small genes involved in congenital coagulation and platelet disorders

Molecular testing of congenital coagulation and platelet disorders offers confirmation of clinical diagnoses, supports genetic counselling, and enables predictive and prenatal diagnosis. In some cases, genotype-phenotype correlations are important for predicting the clinical course of the disease and adaptation of individualized therapy. Until recently, genotyping has been mainly performed by Sanger sequencing. While next generation sequencing (NGS) enables the parallel analysis of multiple genes, the cost-value ratio of custom-made panels can be unfavorable for analyses of specific small genes. The aim of this study was to transfer genotyping of small genes involved in congenital coagulation and platelet disorders from Sanger sequencing to an NGS-based method. A LR-PCR approach for target enrichment of the entire genomic regions of the genes F7, F10, F11, F12, GATA1, MYH9, TUBB1 and WAS was combined with high-throughput sequencing on a MiSeq platform. NGS detected all variants that had previously been identified by Sanger sequencing. Our results demonstrate that this approach is an accurate and flexible tool for molecular genetic diagnostics of single small genes.Molecular testing of congenital coagulation and platelet disorders offers confirmation of clinical diagnoses, supports genetic counselling, and enables predictive and prenatal diagnosis. In some cases, genotype-phenotype correlations are important for predicting the clinical course of the disease and adaptation of individualized therapy. Until recently, genotyping has been mainly performed by Sanger sequencing. While next generation sequencing (NGS) enables the parallel analysis of multiple genes, the cost-value ratio of custom-made panels can be unfavorable for analyses of specific small genes. The aim of this study was to transfer genotyping of small genes involved in congenital coagulation and platelet disorders from Sanger sequencing to an NGS-based method. A LR-PCR approach for target enrichment of the entire genomic regions of the genes F7, F10, F11, F12, GATA1, MYH9, TUBB1 and WAS was combined with high-throughput sequencing on a MiSeq platform. NGS detected all variants that had previously been identified by Sanger sequencing. Our results demonstrate that this approach is an accurate and flexible tool for molecular genetic diagnostics of single small genes.Molecular testing of congenital coagulation and platelet disorders offers confirmation of clinical diagnoses, supports genetic counselling, and enables predictive and prenatal diagnosis. In some cases, genotype-phenotype correlations are important for predicting the clinical course of the disease and adaptation of individualized therapy. Until recently, genotyping has been mainly performed by Sanger sequencing. While next generation sequencing (NGS) enables the parallel analysis of multiple genes, the cost-value ratio of custom-made panels can be unfavorable for analyses of specific small genes. The aim of this study was to transfer genotyping of small genes involved in congenital coagulation and platelet disorders from Sanger sequencing to an NGS-based method. A LR-PCR approach for target enrichment of the entire genomic regions of the genes F7, F10, F11, F12, GATA1, MYH9, TUBB1 and WAS was combined with high-throughput sequencing on a MiSeq platform. NGS detected all variants that had previously been identified by Sanger sequencing. Our results demonstrate that this approach is an accurate and flexible tool for molecular genetic diagnostics of single small genes.

Diagnostische Einzelgenanalysen jenseits von Sanger – ökonomische Hochdurchsatzsequenzierung kleiner Gene für hereditäre Gerinnungs- und Thrombozytenstörungen

Molecular testing of congenital coagulation and platelet disorders offers confirmation of clinical diagnoses, supports genetic counselling, and enables predictive and prenatal diagnosis. In some cases, genotype-phenotype correlations are important for predicting the clinical course of the disease and adaptation of individualized therapy. Until recently, genotyping has been mainly performed by Sanger sequencing. While next generation sequencing (NGS) enables the parallel analysis of multiple genes, the cost-value ratio of custom-made panels can be unfavorable for analyses of specific small genes. The aim of this study was to transfer genotyping of small genes involved in congenital coagulation and platelet disorders from Sanger sequencing to an NGS-based method. A LR-PCR approach for target enrichment of the entire genomic regions of the genes F7, F10, F11, F12, GATA1, MYH9, TUBB1 and WAS was combined with high-throughput sequencing on a MiSeq platform. NGS detected all variants that had previously been identified by Sanger sequencing. Our results demonstrate that this approach is an accurate and flexible tool for molecular genetic diagnostics of single small genes.Molecular testing of congenital coagulation and platelet disorders offers confirmation of clinical diagnoses, supports genetic counselling, and enables predictive and prenatal diagnosis. In some cases, genotype-phenotype correlations are important for predicting the clinical course of the disease and adaptation of individualized therapy. Until recently, genotyping has been mainly performed by Sanger sequencing. While next generation sequencing (NGS) enables the parallel analysis of multiple genes, the cost-value ratio of custom-made panels can be unfavorable for analyses of specific small genes. The aim of this study was to transfer genotyping of small genes involved in congenital coagulation and platelet disorders from Sanger sequencing to an NGS-based method. A LR-PCR approach for target enrichment of the entire genomic regions of the genes F7, F10, F11, F12, GATA1, MYH9, TUBB1 and WAS was combined with high-throughput sequencing on a MiSeq platform. NGS detected all variants that had previously been identified by Sanger sequencing. Our results demonstrate that this approach is an accurate and flexible tool for molecular genetic diagnostics of single small genes.Molecular testing of congenital coagulation and platelet disorders offers confirmation of clinical diagnoses, supports genetic counselling, and enables predictive and prenatal diagnosis. In some cases, genotype-phenotype correlations are important for predicting the clinical course of the disease and adaptation of individualized therapy. Until recently, genotyping has been mainly performed by Sanger sequencing. While next generation sequencing (NGS) enables the parallel analysis of multiple genes, the cost-value ratio of custom-made panels can be unfavorable for analyses of specific small genes. The aim of this study was to transfer genotyping of small genes involved in congenital coagulation and platelet disorders from Sanger sequencing to an NGS-based method. A LR-PCR approach for target enrichment of the entire genomic regions of the genes F7, F10, F11, F12, GATA1, MYH9, TUBB1 and WAS was combined with high-throughput sequencing on a MiSeq platform. NGS detected all variants that had previously been identified by Sanger sequencing. Our results demonstrate that this approach is an accurate and flexible tool for molecular genetic diagnostics of single small genes.

Faktor-XII-Mangel, APC-Resistenz, Hyperhomocysteinämie und von-Willebrand-Erkrankung Typ 1 in einer Familie

ZusammenfassungEine junge Frau mit verstärkten Regelblutungen und länger anhaltenden Blutungen aus nur geringgradigen Verletzungen wurde untersucht, wobei eine sehr stark verlängerte PTT ( >200 s) auffiel. Die Messung der Faktor-XII-Aktivität ergab mit weniger als 2% einen hochgradigen Mangel. Die angegebenen Blutungssymptome sind jedoch auf eine gleichzeitig bestehende von-Willebrand-Erkrankung Typ 1 zurückzuführen. Zusätzlich waren die APC-Resistenz pathologisch und die Homocysteinkonzentration im Plasma der Patientin erhöht. Auf genomischer Ebene konnten die Mutationen G1691:A im Faktor-V-Gen und C677:T im Methylentetrahydrofolatreduktase(MTHFR)-Gen heterozygot nachgewiesen werden. Die Analyse des Faktor-XII-Gens ergab eine Punktmutation in der Promotorregion (G:C-Transversion, nt–8), die auch im Faktor-XII-Gen des Vaters nachzuweisen ist. Die niedrige Faktor-XII-Aktivität bei der jungen Frau deutet auf die Anwesenheit einer 2. Mutation hin (Compound-Heterozygotie), die sie von ihrer Mutter geerbt haben muß. Diese 2. Mutation ist bis jetzt nicht gefunden worden. Die 15jährige Schwester der Patientin berichtet ebenfalls über verstärkte Regelblutungen. Die Gerinnungsanalyse ergab eine verminderte Faktor-XII-Aktivität und eine von-Willebrand-Erkrankung Typ 1. Die verminderte Faktor-XII-Aktivität ist mit dem heterozygoten Status für diesen Defekt vereinbar. Die erhöht gefundene Resistenz gegenüber APC konnte durch den Nachweis der Mutation G 1691 A im Faktor-V-Gen in heterozygoter Form bestätigt werden. Mutter und Vater der Schwestern sind für den Faktor-XII-Mangel und die Mutation im MTHFR-Gen heterozygot. Bei der Mutter besteht Homozygotie für die Mutation im Faktor-V-Gen (1691 AA). Alle untersuchten Familienmitglieder zeigten erhöhte D-Dimer-Konzentrationen im Plasma. Diskussion: Mit diesem Fallbericht soll auf die Bedeutung der Menorrhagie als häufiges Symptom einer von-Willebrand-Erkrankung hingewiesen werden. Da zusätzlich Risikofaktoren für eine Thrombophilie bestehen, wird auf die Probleme, die den Patientinnen aus der Anwendung oraler Kontrazeptiva entstehen können, ebenso hingewiesen wie auf mögliche Komplikationen im Verlauf einer Schwangerschaft.SummaryA young woman presenting with marked menstrual blood loss and prolonged bleeding after only minimal injuries was investigated. Because of an extremely prolonged PTT (more than 200 s) we measured the factor XII activity and found a severe deficiency. The bleeding symptoms however could be ascribed to the existence of von Willebrands disease type 1. In addition, the patient had an elevated resistance against activated protein C (APC-resistance) and a moderately elevated concentration of homocysteine in her blood plasma. At the genomic level we found heterozygosity for the factor V mutation G 1691 A and the mutation C 677 T in the methylenetetrahydrofolate reductase (MTHFR)-gene. The analysis of the factor XII gene revealed the existence of a point mutation in the promoter region (G→C transversion, nt–8). The same mutation could be found in the paternal factor XII gene. The low factor XII activity in the woman seems to be the result of a second mutation originating from the maternal factor XII gene (compound heterozygosity). However, this second mutation could not be found up to now. In the sister of the women, a 15 year old girl, there is also a marked menstrual blood loss. The coagulation analysis revealed reduced activities of the factor XII and also von Willebrands disease type 1. The reduced factor XII activity seems to be compatible with the heterozygous state of factor XII deficiency. In the girl there was also an increased APC resistance, corresponding with heterozygosity for the factor V mutation G 1691 A. Mother and father are heterozygous for the factor XII deficiency and the mutation C 677 T in the MTHFR gene. In the mother homozygosity for the mutation in the factor V gene (1691 AA) could be found. All family members investigated exhibited elevated D-dimer concentrations in the plasma. Discussion: It is the aim of this report to give attention to menorrhagias as predominant features of von Willebrand’s disease in females. Furthermore in women with von Willebrand’s disease in combination with inherited risk factors for thrombophilia problems could arise from the use of oral contraceptives and also during pregnancy. In our opinion, physicians, especially paediatricians, who take care of adolescents, should be familiar with such problems.