Mitteldeutscher Praxisverbund Humangenetik

Dresden, Germany

Mitteldeutscher Praxisverbund Humangenetik

Dresden, Germany

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Tucci A.,University College London | Kara E.,University College London | Schossig A.,Innsbruck Medical University | Wolf N.I.,VU University Amsterdam | And 26 more authors.
Human Mutation | Year: 2013

Kohlschütter-Tönz syndrome (KTS) is a rare autosomal recessive disorder characterized by amelogenesis imperfecta, psychomotor delay or regression and seizures starting early in childhood. KTS was established as a distinct clinical entity after the first report by Kohlschütter in 1974, and to date, only a total of 20 pedigrees have been reported. The genetic etiology of KTS remained elusive until recently when mutations in ROGDI were independently identified in three unrelated families and in five likely related Druze families. Herein, we report a clinical and genetic study of 10 KTS families. By using a combination of whole exome sequencing, linkage analysis, and Sanger sequencing, we identify novel homozygous or compound heterozygous ROGDI mutations in five families, all presenting with a typical KTS phenotype. The other families, mostly presenting with additional atypical features, were negative for ROGDI mutations, suggesting genetic heterogeneity of atypical forms of the disease. © 2012 Wiley Periodicals, Inc.


Bisschoff I.J.,Albert Ludwigs University of Freiburg | Zeschnigk C.,Albert Ludwigs University of Freiburg | Horn D.,Charité - Medical University of Berlin | Wellek B.,Johannes Gutenberg University Mainz | And 25 more authors.
Human Mutation | Year: 2013

OFD1, now recognized as a ciliopathy, is characterized by malformations of the face, oral cavity and digits, and is transmitted as an X-linked condition with lethality in males. Mutations in OFD1 also cause X-linked Joubert syndrome (JBTS10) and Simpson-Golabi-Behmel syndrome type 2 (SGBS2). We have studied 55 sporadic and six familial cases of suspected OFD1. Comprehensive mutation analysis in OFD1 revealed mutations in 37 female patients from 30 families; 22 mutations have not been previously described including two heterozygous deletions spanning OFD1 and neighbouring genes. Analysis of clinical findings in patients with mutations revealed that oral features are the most reliable diagnostic criteria. A first, detailed evaluation of brain MRIs from seven patients with cognitive defects illustrated extensive variability with the complete brain phenotype consisting of complete agenesis of the corpus callosum, large single or multiple interhemispheric cysts, striking cortical infolding of gyri, ventriculomegaly, mild molar tooth malformation and moderate to severe cerebellar vermis hypoplasia. Although the OFD1 gene apparently escapes X-inactivation, skewed inactivation was observed in seven of 14 patients. The direction of skewing did not correlate with disease severity, reinforcing the hypothesis that additional factors contribute to the extensive intrafamilial variability. © 2012 Wiley Periodicals, Inc.


Kratz C.P.,Hannover Medical School | Franke L.,University Hospital Magdeburg | Peters H.,Institute of Medical and Human Genetics | Kohlschmidt N.,Institute For Klinische Genetik | And 28 more authors.
British Journal of Cancer | Year: 2015

Background:Somatic mutations affecting components of the Ras-MAPK pathway are a common feature of cancer, whereas germline Ras pathway mutations cause developmental disorders including Noonan, Costello, and cardio-facio-cutaneous syndromes. These 'RASopathies' also represent cancer-prone syndromes, but the quantitative cancer risks remain unknown.Methods:We investigated the occurrence of childhood cancer including benign and malignant tumours of the central nervous system in a group of 735 individuals with germline mutations in Ras signalling pathway genes by matching their information with the German Childhood Cancer Registry.Results:We observed 12 cases of cancer in the entire RASopathy cohort vs 1.12 expected (based on German population-based incidence rates). This corresponds to a 10.5-fold increased risk of all childhood cancers combined (standardised incidence ratio (SIR)=10.5, 95% confidence interval=5.4-18.3). The specific cancers included juvenile myelomonocytic leukaemia=4; brain tumour=3; acute lymphoblastic leukaemia=2; rhabdomyosarcoma=2; and neuroblastoma=1. The childhood cancer SIR in Noonan syndrome patients was 8.1, whereas that for Costello syndrome patients was 42.4.Conclusions:These data comprise the first quantitative evidence documenting that the germline mutations in Ras signalling pathway genes are associated with increased risks of both childhood leukaemia and solid tumours. © 2015 Cancer Research UK. All rights reserved.


Verloes A.,University Paris Diderot | Verloes A.,French Institute of Health and Medical Research | Di Donato N.,Carl Gustav Carus Institute | Masliah-Planchon J.,University Paris Diderot | And 47 more authors.
European Journal of Human Genetics | Year: 2015

Baraitser-Winter, Fryns-Aftimos and cerebrofrontofacial syndrome types 1 and 3 have recently been associated with heterozygous gain-of-function mutations in one of the two ubiquitous cytoplasmic actin-encoding genes ACTB and ACTG1 that encode β- and γ-actins. We present detailed phenotypic descriptions and neuroimaging on 36 patients analyzed by our group and six cases from the literature with a molecularly proven actinopathy (9 ACTG1 and 33 ACTB). The major clinical anomalies are striking dysmorphic facial features with hypertelorism, broad nose with large tip and prominent root, congenital non-myopathic ptosis, ridged metopic suture and arched eyebrows. Iris or retinal coloboma is present in many cases, as is sensorineural deafness. Cleft lip and palate, hallux duplex, congenital heart defects and renal tract anomalies are seen in some cases. Microcephaly may develop with time. Nearly all patients with ACTG1 mutations, and around 60% of those with ACTB mutations have some degree of pachygyria with anteroposterior severity gradient, rarely lissencephaly or neuronal heterotopia. Reduction of shoulder girdle muscle bulk and progressive joint stiffness is common. Early muscular involvement, occasionally with congenital arthrogryposis, may be present. Progressive, severe dystonia was seen in one family. Intellectual disability and epilepsy are variable in severity and largely correlate with CNS anomalies. One patient developed acute lymphocytic leukemia, and another a cutaneous lymphoma, indicating that actinopathies may be cancer-predisposing disorders. Considering the multifaceted role of actins in cell physiology, we hypothesize that some clinical manifestations may be partially mutation specific. Baraitser-Winter cerebrofrontofacial syndrome is our suggested designation for this clinical entity. © 2015 Macmillan Publishers Limited All rights reserved.


PubMed | Zentrum fur Humangenetik, MVZ genteQ, U.S. National Cancer Institute, Mitteldeutscher Praxisverbund Humangenetik and 23 more.
Type: Journal Article | Journal: British journal of cancer | Year: 2015

Somatic mutations affecting components of the Ras-MAPK pathway are a common feature of cancer, whereas germline Ras pathway mutations cause developmental disorders including Noonan, Costello, and cardio-facio-cutaneous syndromes. These RASopathies also represent cancer-prone syndromes, but the quantitative cancer risks remain unknown.We investigated the occurrence of childhood cancer including benign and malignant tumours of the central nervous system in a group of 735 individuals with germline mutations in Ras signalling pathway genes by matching their information with the German Childhood Cancer Registry.We observed 12 cases of cancer in the entire RASopathy cohort vs 1.12 expected (based on German population-based incidence rates). This corresponds to a 10.5-fold increased risk of all childhood cancers combined (standardised incidence ratio (SIR)=10.5, 95% confidence interval=5.4-18.3). The specific cancers included juvenile myelomonocytic leukaemia=4; brain tumour=3; acute lymphoblastic leukaemia=2; rhabdomyosarcoma=2; and neuroblastoma=1. The childhood cancer SIR in Noonan syndrome patients was 8.1, whereas that for Costello syndrome patients was 42.4.These data comprise the first quantitative evidence documenting that the germline mutations in Ras signalling pathway genes are associated with increased risks of both childhood leukaemia and solid tumours.


Al-Achkar W.,Syrian Atomic Energy Commission | Wafa A.,Syrian Atomic Energy Commission | Assaad M.,Syrian Atomic Energy Commission | Ehlers C.,Mitteldeutscher Praxisverbund Humangenetik | Liehr T.,Jena University Hospital
Molecular Medicine Reports | Year: 2013

Small supernumerary marker chromosomes (sSMCs) are present in ~2.6×106 individuals worldwide. Concerning their clinical consequences as well as their chromosomal origin and shape, sSMCs are a heterogeneous group of derivative chromosomes; 70% of sSMC carriers are clinically normal. In the present study, we report on a female with mosaicism (45%) of a de novo sSMC derived from chromosome 7, in which the observed clinical signs do not correspond to comparable cases in the literature. She is clinically normal apart from problems in gender determination, a uterus without ovaries and an external penis, pointing overall towards an adrenogenital syndrome (AGS). 21-Hydroxylase deficiency (21-OHD) is the most common cause of AGS. A corresponding analysis for underlying mutations in the CYP21A2 gene revealed a homozygous mutation c.518T>A (p.Ile173Asn) inherited from both non-related parents. Overall, in this study, we report a unique case of female pseudohermaphroditism, classified as a simple virilization form of 21-OHD having an additional minute-shaped chromosome 7 [min(7)(:p11.1->q11.23:)]. Notably, AGS was due to a mutation in the CYP21A2 gene located on chromosome 6. This is a further example that detection of an sSMC does not always resolve the clinical case.


Reuter M.S.,Friedrich - Alexander - University, Erlangen - Nuremberg | Schwabe G.C.,Childrens Hospital | Ehlers C.,Mitteldeutscher Praxisverbund Humangenetik | Marschall C.,Center for Human Genetics and Laboratory Medicine | And 3 more authors.
European Journal of Medical Genetics | Year: 2013

Osteogenesis imperfecta is a heritable connective tissue disorder characterized by variable symptoms including predisposition to fractures. Despite the identification of numerous mutations, a reliable genotype-phenotype correlation has remained notoriously difficult. We now describe two patients with osteogenesis imperfecta and novel, so far undescribed mutations in the COL1A2 gene, further highlighting this complexity. A 3-year-old patient presented with features reminiscent of a connective tissue disorder, with joint hypermobility, Wormian bones, streaky lucencies in the long bones and relative macrocephaly. The patient carried a heterozygous c.1316G>A (p.Gly439Asp) mutation in the COL1A2 gene located in a triple-helix region, in which glycine substitutions have been assumed to cause perinatal lethal OI (Sillence type II). A second family with type I osteogenesis imperfecta carried a heterozygous nonsense mutation c.4060C>T (p.Gln1354X) within the last exon of COL1A2. Whereas other heterozygous nonsense mutations in COL1A2 do not lead to a phenotype, in this case the mRNA is presumed to escape nonsense-mediated decay. Therefore the predicted COL1A2 propeptide lacks the last 13C-terminal amino acids, suggesting that the OI phenotype results from decelerated assembly and overmodification of the collagen triple helix. The presented COL1A2 mutations exemplify the complexity of COL1A2 genotype-phenotype correlation in genetic counselling in OI. © 2013 Elsevier Masson SAS.


Hackmann K.,TU Dresden | Stadler A.,TU Dresden | Schallner J.,Universitatsklinikum Carl Gustav Carus | Franke K.,Mitteldeutscher Praxisverbund Humangenetik | And 8 more authors.
American Journal of Medical Genetics, Part A | Year: 2013

We report on a de novo 0.5Mb triplication (partial tetrasomy) of chromosome 17q25.3 in a 10-year-old girl with severe intellectual disability, infantile seizures (West syndrome), moderate hearing loss, Dandy-Walker malformation, microcephaly, craniofacial dysmorphism, striking cutaneous syndactyly (hands 3-4, feet 2-3), joint laxity, and short stature. The triplication resulted from the unusual combination of a terminal duplication at 17qter and a cryptic translocation of an extra copy of the same segment onto chromosome 10qter. The breakpoint at 17q25.3 was located within the FOXK2 gene. SNP chip analysis suggested that the rearrangement occurred during paternal meiosis involving both paternal chromosomes 17. © 2013 Wiley Periodicals, Inc.

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