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Tübingen, Germany

Karle K.N.,University of Tubingen | Karle K.N.,German Center for Neurodegenerative Diseases | Biskup S.,University of Tubingen | Biskup S.,German Center for Neurodegenerative Diseases | And 11 more authors.
Neurology | Year: 2013

Objective: Hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) is caused by autosomal-dominantly inherited mutations in the colony stimulating factor 1 receptor (CSF1R) gene, and is clinically characterized by a progressive cognitive and motor decline leading to death within several years. Methods: In a continuous series of 25 patients with adult-onset leukoencephalopathy of unknown cause, we genetically confirmed HDLS in 6 families. Affected and nonaffected individuals were examined clinically and by brain MRI studies. Results: HDLS presented as prominent dementia and apraxia, often with extrapyramidal and pyramidal signs, rarely with ataxia. White matter MRI changes were detectable early in the disease course. Family history was negative in 4 of 6 index patients. In 2 of 6 index patients, we could confirm the occurrence of de novo mutations in the CSF1R gene. One family showed possible incomplete penetrance: the 69-year-old father of the index patient carried a CSF1R mutation but was clinically unaffected. In one family, the parents were apparently unaffected and not available for genetic testing. Conclusions: Typical clinical phenotype and early brain MRI alterations can help to guide the diagnosis of HDLS. Because we confirmed de novo mutations in one-third of patients with CSF1R mutations, this diagnosis should be considered even in the absence of a family history. Furthermore, we present evidence for reduced penetrance of a CSF1R mutation. These results have substantial impact for genetic counseling of asymptomatic individuals at risk and should foster research into disease-modifying factors. © 2013 American Academy of Neurology.

Lechner S.,Heinrich Heine University Dusseldorf | Lechner S.,CeGaT GmbH | Ferretti L.,University Pierre and Marie Curie | Ferretti L.,College de France | And 4 more authors.
Molecular Biology and Evolution | Year: 2014

Deciphering the evolutionary processes driving nucleotide variation in multiallelic genes is limited by the number of genetic systems in which such genes occur. The complementary sex determiner (csd) gene in the honey bee Apis mellifera is an informative example for studying allelic diversity and the underlying evolutionary forces in a well-described model of balancing selection. Acting as the primary signal of sex determination, diploid individuals heterozygous for csd develop into females, whereas csd homozygotes are diploid males that have zero fitness. Examining 77 of the functional heterozygous csd allele pairs, we established a combinatorical criteria that provide insights into the minimum number of amino acid differences among those pairs. Given a data set of 244 csd sequences, we show that the total number of csd alleles found in A. mellifera ranges from 53 (locally) to 87 (worldwide), which is much higher than was previously reported (20). Using a coupon-collector model, we extrapolate the presence of in total 116-145 csd alleles worldwide. The hypervariable region (HVR) is of particular importance in determining csd allele specificity, and we provide for this region evidence of high evolutionary rate for length differences exceeding those of microsatellites. The proportion of amino acids driven by positive selection and the rate of nonsynonymous substitutions in the HVR-flanking regions reach values close to 1 but differ with respect to the HVR length. Using a model of csd coalescence, we identified the high originating rate of csd specificities as a major evolutionary force, leading to an origin of a novel csd allele every 400,000 years. The csd polymorphism frequencies in natural populations indicate an excess of new mutations, whereas signs of ancestral transspecies polymorphism can still be detected. This study provides a comprehensive view of the enormous diversity and the evolutionary forces shaping a multiallelic gene. © 2013 The Author.

Szolek A.,University of Tubingen | Schubert B.,University of Tubingen | Mohr C.,University of Tubingen | Sturm M.,University of Tubingen | And 2 more authors.
Bioinformatics | Year: 2014

Motivation: The human leukocyte antigen (HLA) gene cluster plays a crucial role in adaptive immunity and is thus relevant in many biomedical applications. While next-generation sequencing data are often available for a patient, deducing the HLA genotype is difficult because of substantial sequence similarity within the cluster and exceptionally high variability of the loci. Established approaches, therefore, rely on specific HLA enrichment and sequencing techniques, coming at an additional cost and extra turnaround time. Result: We present OptiType, a novel HLA genotyping algorithm based on integer linear programming, capable of producing accurate predictions from NGS data not specifically enriched for the HLA cluster. We also present a comprehensive benchmark dataset consisting of RNA, exome and whole-genome sequencing data. OptiType significantly outperformed previously published in silico approaches with an overall accuracy of 97% enabling its use in a broad range of applications. © The Author 2014. Published by Oxford University Press.

Chae E.,Max Planck Institute for Developmental Biology | Bomblies K.,Max Planck Institute for Developmental Biology | Bomblies K.,Harvard University | Kim S.-T.,Max Planck Institute for Developmental Biology | And 19 more authors.
Cell | Year: 2014

Intraspecific genetic incompatibilities prevent the assembly of specific alleles into single genotypes and influence genome- and species-wide patterns of sequence variation. A common incompatibility in plants is hybrid necrosis, characterized by autoimmune responses due to epistatic interactions between natural genetic variants. By systematically testing thousands of F1 hybrids of Arabidopsis thaliana strains, we identified a small number of incompatibility hot spots in the genome, often in regions densely populated by nucleotide-binding domain and leucine-rich repeat (NLR) immune receptor genes. In several cases, these immune receptor loci interact with each other, suggestive of conflict within the immune system. A particularly dangerous locus is a highly variable cluster of NLR genes, DM2, which causes multiple independent incompatibilities with genes that encode a range of biochemical functions, including NLRs. Our findings suggest that deleterious interactions of immune receptors limit the combinations of favorable disease resistance alleles accessible to plant genomes. © 2014 Elsevier Inc.

Lemke J.R.,University of Bern | Lemke J.R.,University of Leipzig | Kernland-Lang K.,University of Bern | Hortnagel K.,CeGaT GmbH | Itin P.,University of Basel
Dermatology | Year: 2014

Human genodermatoses represent a broad and partly confusing spectrum of countless rare diseases with confluent and overlapping phenotypes often impeding a precise diagnosis in an affected individual. High-throughput sequencing techniques have expedited the identification of novel genes and have dramatically simplified the establishment of genetic diagnoses in such heterogeneous disorders. The precise genetic diagnosis of a skin disorder is crucial for the appropriate counselling of patients and their relatives regarding the course of the disease, prognosis and recurrence risks. Understanding the underlying pathophysiology is a prerequisite to understanding the disease and developing specific, targeted or individualized therapeutic approaches. We aimed to create a comprehensive overview of human genodermatoses and their respective genetic aetiology known to date. We hope this may represent a useful tool in guiding dermatologists towards genetic diagnoses, providing patients with individual knowledge on the respective disorder and applying novel research findings to clinical practice. © 2014 S. Karger AG, Basel.

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