Publications by authors named "Holger Tönnies"

54 Publications

[Genetic counseling in Germany: development of demand].

Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2020 Sep;63(9):1161-1167

Institut für Humangenetik, Universitätsklinikum Münster, Münster, Deutschland.

Background: With the Act on Genetic Testing (GenDG), the German legislator has issued far-reaching regulations for human genetic services, including genetic counseling. This paper presents data on the use of human genetic counseling in the years before and after the entry into force of GenDG in order to provide an informed assessment of the possible effects of the law.

Materials And Methods: Over a period of 13 years (2005 to 2017), the human genetic counseling services provided within the framework of the statutory health insurance and billable by EBM via the Kassenärztliche associations were recorded via a database query at the Central Institute of the National Association of Statutory Health Insurance Physicians (ZI-KBV) and via individual Kassenärztliche Vereinigungen Deutschlands. For the discussion of the observable development of using genetic counseling and possible future development, additional data on the referral behavior, the waiting times, processing time, and reasons for consultations were extracted from the GenBIn database.

Results And Discussion: Demand for genetic counseling has steadily increased at an average rate of approximately 6% per year since 2009. This increase started well before the enactment of the GenDG and may be attributed to a multiplicity of factors. Change in demand for genetic counseling is characterized by increasing self-referrals and by increasing referrals by specialists other than obstetricians/gynecologists. Waiting times between 2011 and 2016/2017 have increased. While demand has been growing, the number of key service providers, the contracted medical specialists in human genetics, has remained almost constant. It is foreseeable that capacity limits will be reached if both trends continue.
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http://dx.doi.org/10.1007/s00103-020-03206-8DOI Listing
September 2020

Complex and Dynamic Chromosomal Rearrangements in a Family With Seemingly Non-Mendelian Inheritance of Dopa-Responsive Dystonia.

JAMA Neurol 2017 07;74(7):806-812

Institute of Neurogenetics, University Lübeck, Lübeck, Germany.

Importance: Chromosomal rearrangements are increasingly recognized to underlie neurologic disorders and are often accompanied by additional clinical signs beyond the gene-specific phenotypic spectrum.

Objective: To elucidate the causal genetic variant in a large US family with co-occurrence of dopa-responsive dystonia as well as skeletal and eye abnormalities (ie, ptosis, myopia, and retina detachment).

Design, Setting, And Participants: We examined 10 members of a family, including 5 patients with dopa-responsive dystonia and skeletal and/or eye abnormalities, from a US tertiary referral center for neurological diseases using multiple conventional molecular methods, including fluorescence in situ hybridization and array comparative genomic hybridization as well as large-insert whole-genome sequencing to survey multiple classes of genomic variations. Of note, there was a seemingly implausible transmission pattern in this family due to a mutation-negative obligate mutation carrier.

Main Outcomes And Measures: Genetic diagnosis in affected family members and insight into the formation of large deletions.

Results: Four members were diagnosed with definite and 1 with probable dopa-responsive dystonia. All 5 affected individuals carried a large heterozygous deletion encompassing all 6 exons of GCH1. Additionally, all mutation carriers had congenital ptosis requiring surgery, 4 had myopia, 2 had retinal detachment, and 2 showed skeletal abnormalities of the hands, ie, polydactyly or syndactyly or missing a hand digit. Two individuals were reported to be free of any disease. Analyses revealed complex chromosomal rearrangements on chromosome 14q21-22 in unaffected individuals that triggered the expansion to a larger deletion segregating with affection status. The expansion occurred recurrently, explaining the seemingly non-mendelian inheritance pattern. These rearrangements included a deletion of GCH1, which likely contributes to the dopa-responsive dystonia, as well as a deletion of BMP4 as a potential cause of digital and eye abnormalities.

Conclusions And Relevance: Our findings alert neurologists to the importance of clinical red flags, ie, unexpected co-occurrence of clinical features that may point to the presence of chromosomal rearrangements as the primary disease cause. The clinical management and diagnostics of such patients requires an interdisciplinary approach in modern clinical-diagnostic care.
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http://dx.doi.org/10.1001/jamaneurol.2017.0666DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5710536PMC
July 2017

Predictive genetic testing, risk communication, and risk perception: an international expert meeting in Berlin, Germany.

J Community Genet 2014 Jan 10;5(1):1-5. Epub 2013 Dec 10.

Administrative Office of the German Commission on Genetic Testing, Robert Koch-Institute, Nordufer 20, 13353, Berlin, Germany,

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http://dx.doi.org/10.1007/s12687-013-0177-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3890061PMC
January 2014

Reflecting on earlier experiences with unsolicited findings: points to consider for next-generation sequencing and informed consent in diagnostics.

Hum Mutat 2013 Oct 16;34(10):1322-8. Epub 2013 Jul 16.

Department of Clinical Genetics, Section of Community Genetics and the EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.

High-throughput nucleotide sequencing (often referred to as next-generation sequencing; NGS) is increasingly being chosen as a diagnostic tool for cases of expected but unresolved genetic origin. When exploring a higher number of genetic variants, there is a higher chance of detecting unsolicited findings. The consequential increased need for decisions on disclosure of these unsolicited findings poses a challenge for the informed consent procedure. This article discusses the ethical and practical dilemmas encountered when contemplating informed consent for NGS in diagnostics from a multidisciplinary point of view. By exploring recent similar experiences with unsolicited findings in other settings, an attempt is made to describe what can be learned so far for implementing NGS in standard genetic diagnostics. The article concludes with a set of points to consider in order to guide decision-making on the extent of return of results in relation to the mode of informed consent. We hereby aim to provide a sound basis for developing guidelines for optimizing the informed consent procedure.
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http://dx.doi.org/10.1002/humu.22370DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4285964PMC
October 2013

Chromosomal aberrations associated with clonal evolution and leukemic transformation in fanconi anemia: clinical and biological implications.

Anemia 2012 23;2012:349837. Epub 2012 May 23.

c/o Young Oncology Unit, Department of Paediatric and Adolescent Oncology, Christie Hospital, Wilmslow Road, Manchester M20 6XB, UK.

Fanconi anaemia (FA) is an inherited disease with congenital and developmental abnormalities, bone marrow failure, and extreme risk of leukemic transformation. Bone marrow surveillance is an important part of the clinical management of FA and often reveals cytogenetic aberrations. Here, we review bone marrow findings in FA and discuss the clinical and biological implications of chromosomal aberrations associated with leukemic transformation.
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http://dx.doi.org/10.1155/2012/349837DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3366199PMC
August 2012

A de novo 1.1Mb microdeletion of chromosome 19p13.11 provides indirect evidence for EPS15L1 to be a strong candidate for split hand split foot malformation.

Eur J Med Genet 2011 Sep-Oct;54(5):e501-4. Epub 2011 Jun 7.

Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Germany.

We describe a 3.5 year old girl presenting with short stature, developmental delay, marked muscular hypotonia with ataxia, premature pubarche, and dysmorphic features. A 1.07-1.12Mb-sized de novo microdeletion of chromosome 19p13.11 is most likely the cause for the clinical phenotype. The patient did not show any abnormalities of the extremities which contrasts with the finding of one previously reported patient with an overlapping deletion presenting with split hand and foot malformation (SHFM). The remarkable difference is that in the previously described patient but not in the patient reported herein the genes EPS15L1 and CALR3 were deleted. As EPS15L1 has been associated with limb development previously, the presented case provides indirect evidence that this may be a new candidate gene for SHFM. A possible genotype-phenotype correlation is provided based on literature review and comparison of our patient to the previously reported patients with overlapping or partly overlapping copy number variations in 19p13.11.
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http://dx.doi.org/10.1016/j.ejmg.2011.05.004DOI Listing
December 2011

Pyrosequencing-based DNA methylation profiling of Fanconi anemia/BRCA pathway genes in laryngeal squamous cell carcinoma.

Int J Oncol 2011 Aug 11;39(2):505-14. Epub 2011 May 11.

Institute of Human Genetics, University Hospital Schleswig-Holstein, Campus Kiel/Christian-Albrechts, University Kiel, D-24105 Kiel, Germany.

Fanconi anemia (FA) associated genes [FANCA, -B, -C, FANCD1(BRCA2), -D2, -E, -F, -G, -I, -L, -M, FANCN (PALB2), FANCJ(BRIP1) and FA-linked BRCA1] encode proteins of DNA damage response pathways mutated in FA patients. FA is characterized by congenital malformations, chromosomal instability and high cancer susceptibility. FA patients have a 500-700 times higher risk of head and neck squamous cell carcinoma (HNSCC) compared to the non-FA population. As DNA methylation comprises one of the known gene inactivation mechanisms in cancer we have investigated the methylation status of 13 FA and one FA-linked gene in order to assess the role of FA in sporadic laryngeal squamous cell carcinoma (LSCC) tumor samples. Thirteen laryngeal squamous carcinoma cell lines (UT-SCC) and 64 primary laryngeal carcinoma cases were analyzed by bisulfite pyrosequencing. DNA from buccal swabs of 10 healthy volunteers was used as a control group. Promoter regions of FANCA, BRCA1 and BRCA2 displayed recurrent alterations in the methylation levels in cancer samples as compared to buccal swabs controls. For FANCA, hypomethylation was observed in 11/13 cell lines (p<0.0003) and all 64 primary larynx samples (p<0.001) compared to buccal swabs. For BRCA1, 4/13 cell lines (p=0.04) and 3/58 primary laryngeal cases (p=0.22) showed hypomethylation. In BRCA2, all 13 cell lines (p<0.0001) 4/63 primary LSCC (p<0.01) showed hypermethylation as compared to controls. In conclusion, we show recurrent alterations of DNA methylation levels in three Fanconi anemia genes which might contribute to the pathogenesis of LSCC.
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http://dx.doi.org/10.3892/ijo.2011.1039DOI Listing
August 2011

Normal prenatal ultrasound findings in a case with de novo mosaic small supernumerary marker chromosome 18--how to counsel?

J Matern Fetal Neonatal Med 2012 Feb 8;25(2):200-2. Epub 2011 Apr 8.

Department of Gynecology and Obstetrics, Christian-Albrechts-University Kiel and Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel, Germany.

Introduction: We report on a prenatally diagnosed de novo small supernumerary marker chromosome (sSMC) derived form chromosome 18. Molecular cytogenetic studies led to information about the clinical relevance of the sSMC-induced chromosomal imbalance. As prenatal ultrasound was normal, detailed information with respect to prenatal counseling of the parents was necessary. In general, detection of an sSMC requires as much information on the exact genetic content with its possible impact on the phenotype as achievable.

Material And Methods: Amniocentesis was performed in a 37-year-old Gravida IV Para II with a history of an induced abortion due to a prenatally diagnosed trisomy 21. Fluorescence in situ hybridization quick test gave hint on a possible mosaic trisomy 18, whereas the conventional banding cytogenetic analysis revealed an sSMC. The amount of euchromatin was estimated to be less than 5 MB.

Conclusions: sSMC are rare, being present in less than 0.08% of all pregnancies. Going together with an abnormal ultrasound, counseling of the parents is relatively easy to perform. In cases of normal prenatal ultrasound, profound knowledge about the surplus genetic content is necessary for the estimation of the fetal outcome prognosis. In the present case, detailed molecular cytogenetics techniques led the parents to continue the pregnancy.
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http://dx.doi.org/10.3109/14767058.2011.566949DOI Listing
February 2012

Dosage effect of zero to three functional LBR-genes in vivo and in vitro.

Nucleus 2010 Mar-Apr;1(2):179-89. Epub 2010 Jan 3.

Institute of Medical Genetics, Charité University Medicine, Berlin, Germany.

The Lamin B receptor (LBR) is a pivotal architectural protein in the nuclear envelope. Mutations in the Lamin B receptor lead to nuclear hyposegmentation (Pelger-Huët anomaly). We have exactly quantified the nuclear lobulation in neutrophils from individuals with 0, 1, 2 and 3 functional copies of the lamin B receptor gene and analyzed the effect of different mutation types. Our data demonstrate that there is a highly significant gene-dosage effect between the gene copy number and the nuclear segmentation index of neutrophils. This finding is paralleled by a dose-dependent increase in LBR protein and staining intensity of the nuclear membrane in corresponding lymphoblastoid cell lines, which demonstrates a significant correlation on the protein level as well. We further show that LBR expression continually increases during granulopoiesis in vitro from human precursor cells with ovoid nuclei to multi-segmented neutrophil nuclei 11 days later, indicating relevance for regular human granulopoiesis. Altogether, LBR is a unique model that will allow the systematic study of gene-dosage effects and of modifying endogeneous and exogeneous factors on granulopoiesis.
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http://dx.doi.org/10.4161/nucl.1.2.11113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3030694PMC
January 2012

High resolution ArrayCGH and expression profiling identifies PTPRD and PCDH17/PCH68 as tumor suppressor gene candidates in laryngeal squamous cell carcinoma.

Genes Chromosomes Cancer 2011 Mar 7;50(3):154-66. Epub 2010 Dec 7.

Institute of Human Genetics, Polish Academy of Sciences, Poznan, Poland.

Many classical tumor suppressor genes (TSG) were identified by delineation of bi-allelic losses called homozygous deletions. To identify systematically homozygous deletions in laryngeal squamous cell carcinoma (LSCC) and to unravel novel putative tumor suppressor genes, we screened 10 LSCC cell lines using high resolution array comparative genomic hybridization (arrayCGH) and array based expression analysis. ArrayCGH identified altogether 113 regions harboring protein coding genes that showed strong reduction in copy number indicating a potential homozygous deletion. Out of the 113 candidate regions, 22 novel homozygous deletions that affected the coding sequences of 15 genes were confirmed by multiplexPCR. Three genes were homozygously lost in two cell lines: PCDH17/PCH68, PRR20, and PTPRD. For the 15 homozygously deleted genes, four showed statistically significant downregulation of expression in LSCC cell lines as compared with normal human laryngeal controls. These were ATG7 (1/10 cell line), ZMYND11 (BS69) (1/10 cell line), PCDH17/PCH68 (9/10 cell lines), and PTPRD (7/10 cell lines). Quantitative real-time PCR was used to confirm the downregulation of the candidate genes in 10 expression array-studied cell lines and an additional cohort of cell lines; statistical significant downregulation of PCDH17/PCH68 and PTPRD was observed. In line with this also Western blot analyses demonstrated a complete absence of the PCDH17 and PTPRD proteins. Thus, expression profiling confirmed recurrent alterations of two genes identified primarily by delineation of homozygous deletions. These were PCDH17/PCH68, the protocadherin gene, and the STAT3 inhibiting receptor protein tyrosine phosphatase gene PTPRD. These genes are good candidates for novel TSG in LSCC.
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http://dx.doi.org/10.1002/gcc.20840DOI Listing
March 2011

A duplication in 1q21.3 in a family with early onset and childhood absence epilepsy.

Epilepsia 2010 Dec 24;51(12):2453-6. Epub 2010 Sep 24.

Department of Neuropediatrics, University Hospital Schleswig-Holstein, Campus Kiel, Christian-Albrechts-University, Kiel, Germany.

Early onset absence epilepsy (EOAE) starting before the age of 4 years constitutes a rare subgroup of the idiopathic generalized epilepsies (IGEs). A strong genetic component in IGE has been suggested by twin and family studies. We describe a boy with absence seizures starting at the age of 9 months whose parents both had childhood absence epilepsy. A 192-kb duplication in 1q21.3 was identified in the proband and his father, encompassing the gene CHRNB2 coding for the β-2 subunit of the nicotinic acetylcholine receptor and the gene ADAR coding for adenosine deaminase, an enzyme responsible for RNA editing. Both are candidate genes for seizure disorders. The duplication was not identified in 191 independent IGE patients (93 EOAE; 98 classical IGE) or in 1,157 population controls.
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http://dx.doi.org/10.1111/j.1528-1167.2010.02712.xDOI Listing
December 2010

Mutations in GRIN2A and GRIN2B encoding regulatory subunits of NMDA receptors cause variable neurodevelopmental phenotypes.

Nat Genet 2010 Nov 3;42(11):1021-6. Epub 2010 Oct 3.

Institute of Human Genetics, University of Erlangen-Nuremberg, Erlangen, Germany.

N-methyl-D-aspartate (NMDA) receptors mediate excitatory neurotransmission in the mammalian brain. Two glycine-binding NR1 subunits and two glutamate-binding NR2 subunits each form highly Ca²(+)-permeable cation channels which are blocked by extracellular Mg²(+) in a voltage-dependent manner. Either GRIN2B or GRIN2A, encoding the NMDA receptor subunits NR2B and NR2A, was found to be disrupted by chromosome translocation breakpoints in individuals with mental retardation and/or epilepsy. Sequencing of GRIN2B in 468 individuals with mental retardation revealed four de novo mutations: a frameshift, a missense and two splice-site mutations. In another cohort of 127 individuals with idiopathic epilepsy and/or mental retardation, we discovered a GRIN2A nonsense mutation in a three-generation family. In a girl with early-onset epileptic encephalopathy, we identified the de novo GRIN2A mutation c.1845C>A predicting the amino acid substitution p.N615K. Analysis of NR1-NR2A(N615K) (NR2A subunit with the p.N615K alteration) receptor currents revealed a loss of the Mg²(+) block and a decrease in Ca²(+) permeability. Our findings suggest that disturbances in the neuronal electrophysiological balance during development result in variable neurological phenotypes depending on which NR2 subunit of NMDA receptors is affected.
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http://dx.doi.org/10.1038/ng.677DOI Listing
November 2010

Possible genetic heterogeneity of spinocerebellar ataxia linked to chromosome 15.

Mov Disord 2010 Aug;25(11):1577-82

Section of Clinical and Molecular Neurogenetics, Department of Neurology, University of Luübeck, Luübeck, Germany.

Autosomal dominant spinocerebellar ataxias (SCAs) are a clinically and genetically heterogeneous group of neurodegenerative disorders. We investigated an SCA family from Serbia of Roma ethnic origin; four affected and nine unaffected family members underwent a detailed neurological examination. The presenting symptom in all patients was gait unsteadiness in early adulthood. Additional features included pyramidal signs, depression, and cognitive impairment. The condition follows an autosomal dominant pattern of inheritance. After excluding repeat expansions in nine known SCA genes, a genome-wide linkage analysis with 412 microsatellite markers localized the putative disease gene to a 40.7 cM (42.5 Mb) region on chromosome 15q between markers D15S1006 and D15S116. The maximum model-based multipoint LOD score was 1.75. This region is only 4.3 Mb away from the SCA11 (TTBK2) gene. Accordingly, mutations in TTBK2 were not found, suggesting a second SCA gene on chromosome 15q as cause of this novel form of SCA. In addition, we excluded alterations in two candidate genes in the linked region, namely expansion of a polyglutamine-coding CAG repeat in ARID3B and mutations in SEMA6D.
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http://dx.doi.org/10.1002/mds.22857DOI Listing
August 2010

Deregulation of the telomerase reverse transcriptase (TERT) gene by chromosomal translocations in B-cell malignancies.

Blood 2010 Aug 11;116(8):1317-20. Epub 2010 May 11.

Institute of Human Genetics, Christian-Albrechts University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.

Sequence variants at the TERT-CLPTM1L locus in chromosome 5p have been recently associated with disposition for various cancers. Here we show that this locus including the gene encoding the telomerase reverse-transcriptase TERT at 5p13.33 is rarely but recurrently targeted by somatic chromosomal translocations to IGH and non-IG loci in B-cell neoplasms, including acute lymphoblastic leukemia, chronic lymphocytic leukemia, mantle cell lymphoma and splenic marginal zone lymphoma. In addition, cases with genomic amplification of TERT locus were identified. Tumors bearing chromosomal aberrations involving TERT showed higher TERT transcriptional expression and increased telomerase activity. These data suggest that deregulation of TERT gene by chromosomal abnormalities leading to increased telomerase activity might contribute to B-cell lymphomagenesis.
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http://dx.doi.org/10.1182/blood-2009-09-240440DOI Listing
August 2010

Deletions in 16p13 including GRIN2A in patients with intellectual disability, various dysmorphic features, and seizure disorders of the rolandic region.

Epilepsia 2010 Sep;51(9):1870-3

Northern German Epilepsy Center for Children and Adolescents, Raisdorf, Germany.

Seizure disorders of the rolandic region comprise a spectrum of different epilepsy syndromes ranging from benign rolandic epilepsy to more severe seizure disorders including atypical benign partial epilepsy/pseudo-Lennox syndrome,electrical status epilepticus during sleep, and Landau-Kleffner syndrome. Centrotemporal spikes are the unifying electroencephalographic hallmark of these benign focal epilepsies, indicating a pathophysiologic relationship between the various epilepsies arising from the rolandic region. The etiology of these epilepsies is elusive, but a genetic component is assumed given the heritability of the characteristic electrographic trait. Herein we report on three patients with intellectual disability, various dysmorphic features, and epilepsies involving the rolandic region, carrying previously undescribed deletions in 16p13. The only gene located in the critical region shared by all three patients is GRIN2A coding for the alpha-2 subunit of the neuronal N-methyl-D-aspartate(NMDA) receptor.
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http://dx.doi.org/10.1111/j.1528-1167.2010.02555.xDOI Listing
September 2010

Four patients with speech delay, seizures and variable corpus callosum thickness sharing a 0.440 Mb deletion in region 1q44 containing the HNRPU gene.

Eur J Med Genet 2010 Jul-Aug;53(4):179-85. Epub 2010 Apr 9.

Institute of Human Genetics, University Hospital Schleswig-Holstein Campus Kiel, Christian-Albrechts University, Kiel, Germany.

Structural genome aberrations are frequently associated with highly variable congenital phenotypes involving mental retardation and developmental delay. Although some of these aberrations may result in recognizable phenotypes, a high degree of phenotypic variability often complicates a comprehensive clinical and genetic diagnosis. We describe four patients with overlapping deletions in chromosomal region 1q44, who show developmental delay, in particular of expressive speech, seizures, hypotonia, CNS anomalies, including variable thickness of the abnormal corpus callosum in three of them. High resolution oligonucleotide and SNP array-based segmental aneuploidy profiling showed that these three patients share a 0.440 Mb interstitial deletion, which does not overlap with previously published consensus regions of 1q44 deletions. Two copies of AKT3 and ZNF238, two previously proposed dosage sensitive candidate genes for microcephaly and agenesis of the corpus callosum, were retained in two of our patients. The deletion shared by our patients encompassed the FAM36A, HNRPU, EFCAB2 and KIF26B genes. Since HNRPU is involved in the regulation of embryonic brain development, this represents a novel plausible candidate gene for the combination of developmental delay, speech delay, hypotonia, hypo- or agenesis of the corpus callosum, and seizures in patients with 1q44 deletions. Since only one of the two patients with deletions including the ZNF124 gene showed a vermis hypoplasia, mere hemizygosity for this gene is not sufficient to cause this anomaly. Moreover, to reconcile the variability in the corpus callosum thickness, additional mechanisms, such as unmasking of hemizygous mutations, position effects and possible interactions with other loci need consideration.
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http://dx.doi.org/10.1016/j.ejmg.2010.04.001DOI Listing
October 2010

Two siblings with immunodeficiency, facial abnormalities and chromosomal instability without mutation in DNMT3B gene but liability towards malignancy; a new chromatin disorder delineation?

Mol Cytogenet 2010 Mar 8;3. Epub 2010 Mar 8.

National Medical Center "Mother and Child", Orlovska Street 66, 220053 Minsk, Republic of Belarus.

Background: ICF syndrome (standing for Immunodeficiency, Centromere instability and Facial anomalies syndrome) is a very rare autosomal recessive immune disorder caused by mutations of the gene de novo DNA-methyltransferase 3B (DNMT3B). However, in the literature similar clinical cases without such mutations are reported, as well.

Results: We report on a family in which the unrelated spouses had two female siblings sharing similar phenotypic features resembling ICF-syndrome, i.e. congenital abnormalities, immunodeficiency, developmental delay and high level of chromosomal instability, including high frequency of centromeric/pericentromeric rearrangements and breaks, chromosomal fragments despiralization or pulverization. However, mutations in DNMT3B could not be detected.

Conclusion: The discovery of a new so-called 'chromatin disorder' is suggested. Clinical, molecular genetic and cytogenetic characteristics are reported and compared to other 'chromatin disorders'.
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http://dx.doi.org/10.1186/1755-8166-3-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2844377PMC
March 2010

Deregulated expression of cytokine receptor gene, CRLF2, is involved in lymphoid transformation in B-cell precursor acute lymphoblastic leukemia.

Blood 2009 Sep 29;114(13):2688-98. Epub 2009 Jul 29.

Leukaemia Research Cytogenetics Group, Northern Institute for Cancer Research, Newcastle University, Newcastle, United Kingdom.

We report 2 novel, cryptic chromosomal abnormalities in precursor B-cell acute lymphoblastic leukemia (BCP-ALL): a translocation, either t(X;14)(p22;q32) or t(Y;14)(p11;q32), in 33 patients and an interstitial deletion, either del(X)(p22.33p22.33) or del(Y)(p11.32p11.32), in 64 patients, involving the pseudoautosomal region (PAR1) of the sex chromosomes. The incidence of these abnormalities was 5% in childhood ALL (0.8% with the translocation, 4.2% with the deletion). Patients with the translocation were older (median age, 16 years), whereas the patients with the deletion were younger (median age, 4 years). The 2 abnormalities result in deregulated expression of the cytokine receptor, cytokine receptor-like factor 2, CRLF2 (also known as thymic stromal-derived lymphopoietin receptor, TSLPR). Overexpression of CRLF2 was associated with activation of the JAK-STAT pathway in cell lines and transduced primary B-cell progenitors, sustaining their proliferation and indicating a causal role of CRLF2 overexpression in lymphoid transformation. In Down syndrome (DS) ALL and 2 non-DS BCP-ALL cell lines, CRLF2 deregulation was associated with mutations of the JAK2 pseudokinase domain, suggesting oncogenic cooperation as well as highlighting a link between non-DS ALL and JAK2 mutations.
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http://dx.doi.org/10.1182/blood-2009-03-208397DOI Listing
September 2009

Fluorescence in situ hybridization techniques in medical diagnostics.

Expert Opin Med Diagn 2008 Dec;2(12):1381-90

Centre for Prenatal Diagnosis, Kudamm 199, Berlin 10719, Germany.

Background: Fluorescence in situ hybridization (FISH) has become a well-established method in medical diagnostics. FISH methods complement conventional cytogenetic banding techniques and offer extra clinical applications. FISH is based on the binding of complementary, single-stranded fluorescence-labeled nucleic acid sequences to the fixed and denatured target DNA of metaphases, interphase nuclei or isolated DNA sequences (BACs, oligonucleotides).

Objective: The intent of this article is to review the development of molecular cytogenetic techniques available at present and to summarize the most efficient and appropriate use of these techniques in medical diagnostics. The technical aspects and most important applications of FISH assays are described.

Conclusion: FISH is bridging the gap between conventional cytogenetic banding analysis and molecular genetic DNA studies. The use of FISH techniques enhances the correct interpretation of numerical and structural chromosome aberrations.
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http://dx.doi.org/10.1517/17530050802558899DOI Listing
December 2008

A further case of the recurrent 15q24 microdeletion syndrome, detected by array CGH.

Eur J Pediatr 2008 Aug 12;167(8):903-8. Epub 2007 Oct 12.

Institute of Medical Genetics, Charité Universitätsmedizin Berlin, Campus Virchow Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany.

We report on a 10-year-old patient with developmental delay, craniofacial dysmorphism, digital and genital abnormalities. In addition, muscular hypotonia, strabism, and splenomegaly were observed; inguinal and umbilical hernias were surgically corrected. Mucopolysaccharidoses and CDG syndromes could not be found. Chromosome analysis revealed a normal male karyotype (46,XY). A more detailed investigation of the patient's genomic DNA by microarray-based comparative genomic hybridization (array CGH) detected an interstitial 3.7 Mb deletion ranging from 15q24.1 to 15q24.3 which was shown to be de novo. Interstitial deletions involving 15q24 are rare. Sharp et al. (Hum Mol Genet 16:567-572, 2007) recently characterized a recurrent 15q24 microdeletion syndrome with breakpoints in regions of segmental duplications. The de novo microdeletion described here colocalizes with the minimal deletion region of the 15q24 microdeletion syndrome. The distinct clinical phenotype associated with this novel microdeletion syndrome is similar to the phenotype of our patient with respect to specific facial features, developmental delay, microcephaly, digital abnormalities, and genital abnormalities in males. We present a genotype-phenotype correlation and comparison with patients from the literature.
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http://dx.doi.org/10.1007/s00431-007-0616-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2757600PMC
August 2008

New immortalized cell lines of patients with small supernumerary marker chromosome: towards the establishment of a cell bank.

J Histochem Cytochem 2007 Jun 6;55(6):651-60. Epub 2007 Mar 6.

Institute of Human Genetics, Charité Campus Virchow, Berlin, Germany.

Sixteen newly established cell lines with small supernumerary marker chromosomes (sSMC) derived from chromosomes 1, 2, 4, 6, 7, 8, 14, 15, 16, 18, 19, 21, and 22 are reported. Two sSMC are neocentric and derived from 15q24.1-qter and 2q35-q36, respectively. Two further cases each present with two sSMC of different chromosomal origin. sSMC were characterized by multicolor fluorescence in situ hybridization for their chromosomal origin and genetic content. Moreover, uniparental disomy of the sister chromosomes of the sSMC was excluded in all nine cases studied for that reason. The 16 cases provide information to establish a refined genotype-phenotype correlation of sSMC and are available for future studies.
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http://dx.doi.org/10.1369/jhc.6A7161.2007DOI Listing
June 2007

Molecular cytogenetic characterisation of an interstitial deletion 12p detected by prenatal diagnosis.

Prenat Diagn 2007 May;27(5):475-8

Zentrum für Pränataldiagnostik Kudamm-199, Berlin, Germany.

Objectives: Deletions in the short arm of chromosome 12 are rare structural aberrations. Till now only ten patients with interstitial deletions are described in the literature. Here, we report on the first case detected by prenatal diagnosis. Chorionic villi sampling was performed in the 14th week of gestation, indicated by fetal abnormalities detected by ultrasound examination. Conventional cytogenetic and molecular cytogenetic techniques were applied to determine the correct karyotype of the affected fetus.

Results: Analysing Giemsa- and QFQ-stained chromosomes of the CVS short-term culture, a structural aberrant chromosome 12 was detected. Fluorescence in situ hybridisation with YAC-probes and CGH analysis with DNA extracted from native chorionic villi proved an interstitial deletion in the aberrant chromosome 12. The GTG-banded chromosomes of the CVS long-term culture confirmed these results. Analyses of the parental chromosomal sets yielded normal results, indicating a de novo aberration. Array CGH analysis was performed to determine accurately the deletion breakpoints. Finally, according to ISCN 2005, the karyotype could be determined as 46,XX.arr cgh 12p13.2p11.21(RP11-77I22-->RP11-144O23)x 1.

Conclusion: The presented case shows the power of modern cytogenetic methods, allowing a more detailed diagnosis in affected individuals, and therefore, facilitating a more reliable prenatal diagnosis.
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http://dx.doi.org/10.1002/pd.1703DOI Listing
May 2007

Amplification and translocation of 3q26 with overexpression of EVI1 in Fanconi anemia-derived childhood acute myeloid leukemia with biallelic FANCD1/BRCA2 disruption.

Genes Chromosomes Cancer 2007 Apr;46(4):359-72

Academic Unit of Paediatric Oncology, Christie Hospital Trust, University of anchester, Manchester, UK.

Fanconi anemia (FA) is an inherited disease with congenital abnormalities and an extreme risk of acute myeloid leukemia (AML). Genetic events occurring during malignant transformation in FA and the biology of FA-associated AML are poorly understood, but are often preceded by the development of chromosomal aberrations involving 3q26-29 in bone marrow of FA patients. We report here the molecular cytogenetic characterization of FA-derived AML cell lines SB1685CB and SB1690CB by conventional and array comparative genomic hybridization, fluorescence in situ hybridization, and SKY. We identified gains of a 3.7 MB chromosomal region on 3q26.2-26.31, which preceded transformation to overt leukemia. This region harbors the oncogenic transcription factor EVI1. A third FA-derived cell line, FA-AML1, carried a translocation with ectopic localization of 3q26 including EVI1. Rearrangements of 3q, which are rare in childhood AML, commonly result in overexpression of EVI1, which determines specific gene expression patterns and confers poor prognosis. We detected overexpression of EVI1 in all three FA-derived AML. Our results suggest a link between the FA defect, chromosomal aberrations involving 3q and overexpression of EVI1. We hypothesize that constitutional or acquired FA defects might be a common factor for the development of 3q abnormalities in AML. In addition, cryptic imbalances as detected here might account for overexpression of EVI1 in AML without overt 3q26 rearrangements.
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http://dx.doi.org/10.1002/gcc.20417DOI Listing
April 2007

Successful bone marrow transplantation in a patient with DNA ligase IV deficiency and bone marrow failure.

Orphanet J Rare Dis 2007 Jan 15;2. Epub 2007 Jan 15.

Department of Pediatrics, University of Jena, Kochstr, 2, D-07740 Jena, Germany.

Background: DNA Ligase IV deficiency syndrome is a rare autosomal recessive disorder caused by hypomorphic mutations in the DNA ligase IV gene (LIG4). The clinical phenotype shows overlap with a number of other rare syndromes, including Seckel syndrome, Nijmegen breakage syndrome, and Fanconi anemia. Thus the clinical diagnosis is often delayed and established by exclusion.

Methods: We describe a patient with pre- and postnatal growth retardation and dysmorphic facial features in whom the diagnoses of Seckel-, Dubowitz-, and Nijmegen breakage syndrome were variably considered. Cellular radiosensitivity in the absence of clinical manifestations of Ataxia telangiectasia lead to the diagnosis of DNA ligase IV (LIG4) deficiency syndrome, confirmed by compound heterozygous mutations in the LIG4 gene. At age 11, after a six year history of progressive bone marrow failure and increasing transfusion dependency the patient was treated with matched sibling donor hematopoietic stem cell transplantation (HSCT) using a fludarabine-based conditioning regimen without irradiation.

Results: The post-transplantation course was uneventful with rapid engraftment leading to complete and stable chimerism. Now at age 16, the patient has gained weight and is in good clinical condition.

Conclusion: HSCT using mild conditioning without irradiation qualifies as treatment of choice in LIG4-deficient patients who have a matched sibling donor.
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http://dx.doi.org/10.1186/1750-1172-2-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1781429PMC
January 2007

Nuchal cystic hygroma in five fetuses from 1819 to 1826 in the Meckel-anatomical collections at the University of Halle, Germany.

Am J Med Genet A 2007 Jan;143A(2):119-28

Department of Anatomy and Cell Biology, Martin-Luther University Halle-Wittenberg, Halle/Saale, Germany.

The Anatomical collection of the Department of Anatomy and Cell Biology, Medical School of the University of Halle, Germany, comprises more than 8,000 specimens. Around 600 of them show congenital anomalies. The collection of abnormal human and animal fetuses began as the private collection of Johann Friedrich Meckel the Elder (1724-1774), his son Philipp Friedrich Theodor Meckel (1755-1803) and his grandson Johann Friedrich Meckel the Younger (1781-1833). Meckel the Younger founded the systematic science of developmental pathology. Radiographical techniques, computer tomographic (CT) methods, magnetic resonance imaging (MRI), and comparative genomic hybridization (CGH) were used to diagnose abnormal human fetuses in the Meckel-anatomical collections. Cystic hygroma colli was found in five of the human fetuses originally described by JF Meckel the Younger in 1826 and one of his students in 1819 [Hencke, 1819]. CGH analyses were used to test whether the observed cystic hygroma colli could be caused by chromosomal aneuploidies. CGH-ratio profiles of all chromosomes were apparently normal. PCR-based sex determination tests on ancient DNA were used to determine the fetal gonosomal constitution. It is likely that the Meckel specimens are among the oldest fetuses in which Ullrich-Turner "phenotype" has been diagnosed.
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http://dx.doi.org/10.1002/ajmg.a.31488DOI Listing
January 2007

Symptoms of OTC deficiency but not DMD in a female carrier of an Xp21.1 deletion including the genes for dystrophin and OTC.

Eur J Pediatr 2007 Jul 8;166(7):743-5. Epub 2006 Nov 8.

Institut für Humangenetik, Otto-von-Guericke-Universität, Leipziger Str. 44, 39120 Magdeburg, Germany.

A contiguous deletion encompassing the genes for dystrophin, cytochrome b(-245) beta-subunit (CYBB), retinitis pigmentosa GTPase regulator (RPGR), and OTC was detected in a female patient only suffering from OTC deficiency while symptoms of the other conditions were not present.
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http://dx.doi.org/10.1007/s00431-006-0303-0DOI Listing
July 2007

Complete reversal of ABCG2-depending atypical multidrug resistance by RNA interference in human carcinoma cells.

Oligonucleotides 2006 ;16(3):263-74

Charité Campus Mitte, Institute of Pathology, D-10117 Berlin, Germany.

In the chemotherapeutic treatment of patients with disseminated neoplasms, multidrug resistance (MDR) is a major obstacle. ABCG2 (BCRP/MXR), a member of the superfamily of adenosine triphosphate-binding cassette (ABC) transporters, was demonstrated to be associated with "atypical" forms of multidrug-resistant phenotypes of cancer cells. To overcome the ABCG2-depending MDR, two specific anti-ABCG2 small interfering RNAs (siRNAs) were designed for transient triggering of the gene-silencing RNA interference (RNAi) pathway in the human gastric carcinoma cell line EPG85-257RNOV, exhibiting an atypical MDR phenotype. Because both siRNAs showed biological activity, for stable inhibition of ABCG2 corresponding short hairpin RNA (shRNA) expression vectors were constructed. By treatment of EPG85-257RNOV cells with these constructs, expression of the targeted ABCG2-encoding mRNA and transport protein was inhibited completely. Furthermore, anti-ABCG2 shRNA-treated cells increased cellular drug accumulation to the same level measured in drug-sensitive parental cells. These effects were accompanied by complete reversal of the drug-resistant phenotype. Thus, the data indicate that siRNA- and shRNA-mediated RNAi-based gene therapy may be applicable in preventing and reversing ABCG2-depending atypical MDR.
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http://dx.doi.org/10.1089/oli.2006.16.263DOI Listing
December 2006

CGH of microdissected Kaposi's sarcoma lesions reveals recurrent loss of chromosome Y in early and additional chromosomal changes in late tumour stages.

AIDS 2006 Sep;20(14):1805-12

Immunopathology Laboratory, Department of Pathology and Oncology, Karolinska Institute, Stockholm, Sweden.

Background: It is still unclear if Kaposi's sarcoma (KS) is a monoclonal cell proliferation or a polyclonal, hyperplastic, reactive process. Reports on KS cytogenetics are few and restricted to late stage disease and cell lines.

Method: We analysed 27 KS, early and late, AIDS related (AKS) and endemic (EKS) by laser microdissection, global DNA amplification and comparative genomic hybridization (CGH).

Result: Loss of Y chromosome was detected in 20/23 male KS, which was the only recurrent chromosomal aberration in all nine male early (patch) KS. Only one patch EKS showed in addition to the Y loss a loss of Xq. Late (nodular) AKS and EKS showed recurrent copy number changes in chromosomes 16, 17, 21, X and Y, as well as other random changes. The loss of chromosome 16, 17 and Y was confirmed by interphase fluorescence in situ hybridization (FISH) on paraffin sections. EKS showed a higher number of chromosomal abnormalities than AKS, indicating that rapid growth of AKS is less dependent on genetic changes than is EKS, possibly because of the immunosuppressed host environment in AKS.

Conclusion: Clonal loss of chromosome Y was detected in all early male KS, while additional chromosomal aberrations appeared during development to late KS. This increase in chromosomal abnormalities during tumour growth indicates genetic instability and the selection of survival cell clones establishing late, aggressive sarcoma growth. Our data support the view that KS (in males) develops into a clonal tumour yet initially is a hyperplastic reactive cell proliferation.
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http://dx.doi.org/10.1097/01.aids.0000244199.72887.3dDOI Listing
September 2006