Lemke J.R.,University of Bern |
Riesch E.,CeGaT GmbH |
Scheurenbrand T.,CeGaT GmbH |
Schubach M.,CeGaT GmbH |
And 28 more authors.
Epilepsia | Year: 2012
Summary Purpose: Epilepsies have a highly heterogeneous background with a strong genetic contribution. The variety of unspecific and overlapping syndromic and nonsyndromic phenotypes often hampers a clear clinical diagnosis and prevents straightforward genetic testing. Knowing the genetic basis of a patient's epilepsy can be valuable not only for diagnosis but also for guiding treatment and estimating recurrence risks. Methods: To overcome these diagnostic restrictions, we composed a panel of genes for Next Generation Sequencing containing the most relevant epilepsy genes and covering the most relevant epilepsy phenotypes known so far. With this method, 265 genes were analyzed per patient in a single step. We evaluated this panel on a pilot cohort of 33 index patients with concise epilepsy phenotypes or with a severe but unspecific seizure disorder covering both sporadic and familial cases. Key Findings: We identified presumed disease-causing mutations in 16 of 33 patients comprising sequence alterations in frequently as well as in less commonly affected genes. The detected aberrations encompassed known and unknown point mutations (SCN1A p.R222X, p. E289V, p.379R, p.R393H; SCN2A p.V208E; STXBP1 p.R122X; KCNJ10 p.L68P, p.I129V; KCTD7 p.L108M; KCNQ3 p.P574S; ARHGEF9 p.R290H; SMS p.F58L; TPP1 p.Q278R, p.Q422H; MFSD8 p.T294K), a putative splice site mutation (SCN1A c.693A> p.T/P231P) and small deletions (SCN1A p.F1330Lfs3X [1 bp]; MFSD8 p.A138Dfs10X [7 bp]). All mutations have been confirmed by conventional Sanger sequencing and, where possible, validated by parental testing and segregation analysis. In three patients with either Dravet syndrome or myoclonic epilepsy, we detected SCN1A mutations (p.R222X, p.P231P, p.R393H), even though other laboratories had previously excluded aberrations of this gene by Sanger sequencing or high-resolution melting analysis. Significance: We have developed a fast and cost-efficient diagnostic screening method to analyze the genetic basis of epilepsies. We were able to detect mutations in patients with clear and with unspecific epilepsy phenotypes, to uncover the genetic basis of many so far unresolved cases with epilepsy including mutation detection in cases in which previous conventional methods yielded falsely negative results. Our approach thus proved to be a powerful diagnostic tool that may contribute to collecting information on both common and unknown epileptic disorders and in delineating associated phenotypes of less frequently mutated genes. © 2012 International League Against Epilepsy.
Schanz J.,University of Gottingen |
Haase D.,University of Gottingen |
Steuernagel P.,Institute of Clinical Genetics |
Shirneshan K.,University of Gottingen |
Basecke J.,St. Josefs Hospital
European Journal of Haematology | Year: 2015
A 62-yr-old man with two healthy daughters was diagnosed with osteomyelofibrosis. To our surprise, a female XX-karyotype was observed in bone marrow and confirmed in PHA-stimulated T-lymphocytes from peripheral blood. Further molecular genetic investigation revealed a submicroscopic translocation between the short arm of X and Y, which leads to an XX-male genotype based on an unbalanced translocation X;Y. This rare coincidence was further accentuated as the USP9Y gene, suspected to be to be involved in sperm cell production, was absent, but no azoospermia was present. In general, routine cytogenetics may result in findings that need to be further delineated and, as here, lead to a rare observation. © 2015 John Wiley & Sons A/S.
Ivaskevicius V.,University of Bonn |
Biswas A.,University of Bonn |
Bevans C.,University of Bonn |
Schroeder V.,University of Bern |
And 9 more authors.
Haematologica | Year: 2010
Background: Severe hereditary coagulation factor XIII deficiency is a rare homozygous bleeding disorder affecting one person in every two million individuals. In contrast, heterozygous factor XIII deficiencyis more common, but usually not associated with severe hemorrhage such as intracranialbleeding or hemarthrosis. In most cases, the disease is caused by F13A gene mutations. Causative mutations associated with the F13B gene are rarer. Design and Methods: We analyzed ten index patients and three relatives for factor XIII activity using a photometric assay and sequenced their F13A and F13B genes. Additionally, structural analysis of the wildtype protein structure from a previously reported X-ray crystallographic model identified potential structural and functional effects of the missense mutations. Results: All individuals except one were heterozygous for factor XIIIA mutations (average factor XIII activity 51%), while the remaining homozygous individual was found to have severe factor XIII deficiency (<5% of normal factor XIII activity). Eight of the 12 heterozygous patients exhibited a bleeding tendency upon provocation. Conclusions: The identified missense (Pro289Arg, Arg611His, Asp668Gly) and nonsense (Gly390X, Trp664X) mutations are causative for factor XIII deficiency. A Gly592Ser variant identified in three unrelated index patients, as well as in 200 healthy controls (minor allele frequency 0.005), and two further Tyr167Cys and Arg540Gln variants, represent possible candidates for rare F13A gene polymorphisms since they apparently do not have a significant influence on the structure of the factor XIIIA protein. Future in vitro expression studies of the factor XIII mutations are required to confirm their pathological mechanisms. © 2010 by Ferrata Storti Foundation.
Bogs T.,University of Bonn |
Kipfmuller F.,University of Bonn |
Kohlschmidt N.,Institute of Clinical Genetics |
Gembruch U.,University of Bonn |
And 2 more authors.
Journal of Medical Case Reports | Year: 2016
Background: Previous reports of chromosomal aberrations in different forms of congenital diaphragmatic hernia have been described as comprising aneuploidies (for example, trisomy 21), microdeletions, and duplications (for example, monosomy 15q24, 22q11.2). Case presentation: We describe the first association of a de novo partial tetrasomy 4q35.2 in a father with left-sided, isolated renal agenesis and left-sided, isolated congenital diaphragmatic hernia in his son, who inherited the chromosomal aberration from his father. Conclusions: Given that the aberration occurred de novo in the father and was transmitted to his son, with both presenting with unilateral left-sided developmental field defects, we suggest a gene dosage effect of the tetrasomic region to be involved in the phenotype of our two patients. Furthermore, we suggest performing a genetic workup in multiplex families with congenital malformations. © 2016 Bogs et al.
Neuhann T.M.,Institute of Clinical Genetics |
Artelt J.,Institute of Clinical Genetics |
Tinschert S.,Institute of Clinical Genetics |
Rump A.,Institute of Clinical Genetics
Investigative Ophthalmology and Visual Science | Year: 2011
Purpose. The purpose of the study was to look for ADAMTSL4 mutations in a cohort of German patients with isolated ectopia lentis from nonconsanguineous families. Methods. Mutation screening was performed by PCR amplification of the coding exons of ADAMTSL4 and subsequent sequencing. Results. An identical homozygous deletion of 20 bp of coding sequence within exon 6 (NM_019032.4:c.759_778del20) was identified in eight individuals from seven unrelated families. In a screen of 360 ethnically matched, unaffected individuals, two heterozygous mutation carriers were found. The mutation was always accompanied by the identical haplotype, suggestive of a founder mutation. Conclusions. The results emphasize the association of ADAMTSL4 null mutations with isolated ectopia lentis and the presence of a founder mutation in the European population. Screening of ADAMTSL4 should be considered in all patients with isolated ectopia lentis, with or without family history. In patients from nonconsanguineous families, the authors propose a two-step diagnostic approach, starting with an examination of exon 6 before sequencing the entire coding region of ADAMTSL4. © 2011 The Association for Research in Vision and Ophthalmology, Inc.