Publications by authors named "Ute Grasshoff"

32 Publications

The Role of Neuroimaging and Genetic Analysis in the Diagnosis of Children With Cerebral Palsy.

Front Neurol 2020 9;11:628075. Epub 2021 Feb 9.

Department of Pediatrics, Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.

Cerebral magnetic resonance imaging (MRI) is considered an important tool in the assessment of a child with cerebral palsy (CP), as it is abnormal in more than 80% of children with CP, disclosing the pathogenic pattern responsible for the neurological condition. MRI, therefore, is recommended as the first diagnostic step after medical history taking and neurological examination. With the advances in genetic diagnostics, the genetic contribution to CP is increasingly discussed, and the question arises about the role of genetic testing in the diagnosis of cerebral palsy. The paper gives an overview on genetic findings reported in CP, which are discussed with respect to the underlying brain pathology according to neuroimaging findings. Surveillance of Cerebral Palsy in Europe (SCPE) classifies neuroimaging findings in CP into five categories, which help to stratify decisions concerning genetic testing. Predominant white and gray matter injuries are by far predominant (accounting for around 50 and 20% of the findings). They are considered to be acquired. Here, predisposing genetic factors may play a role to increase vulnerability (and should especially be considered, when family history is positive and/or causative external factors are missing). In maldevelopments and normal findings (around 11% each), monogenic causes are more likely, and thus, genetic testing is clearly recommended. In the miscellaneous category, the precise nature of the MRI finding has to be considered as it could indicate a genetic origin.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fneur.2020.628075DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900404PMC
February 2021

Clinico-Genetic, Imaging and Molecular Delineation of COQ8A-Ataxia: A Multicenter Study of 59 Patients.

Ann Neurol 2020 08 10;88(2):251-263. Epub 2020 Jun 10.

Department of Neurology, Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.

Objective: To foster trial-readiness of coenzyme Q8A (COQ8A)-ataxia, we map the clinicogenetic, molecular, and neuroimaging spectrum of COQ8A-ataxia in a large worldwide cohort, and provide first progression data, including treatment response to coenzyme Q10 (CoQ10).

Methods: Cross-modal analysis of a multicenter cohort of 59 COQ8A patients, including genotype-phenotype correlations, 3D-protein modeling, in vitro mutation analyses, magnetic resonance imaging (MRI) markers, disease progression, and CoQ10 response data.

Results: Fifty-nine patients (39 novel) with 44 pathogenic COQ8A variants (18 novel) were identified. Missense variants demonstrated a pleiotropic range of detrimental effects upon protein modeling and in vitro analysis of purified variants. COQ8A-ataxia presented as variable multisystemic, early-onset cerebellar ataxia, with complicating features ranging from epilepsy (32%) and cognitive impairment (49%) to exercise intolerance (25%) and hyperkinetic movement disorders (41%), including dystonia and myoclonus as presenting symptoms. Multisystemic involvement was more prevalent in missense than biallelic loss-of-function variants (82-93% vs 53%; p = 0.029). Cerebellar atrophy was universal on MRI (100%), with cerebral atrophy or dentate and pontine T2 hyperintensities observed in 28%. Cross-sectional (n = 34) and longitudinal (n = 7) assessments consistently indicated mild-to-moderate progression of ataxia (SARA: 0.45/year). CoQ10 treatment led to improvement by clinical report in 14 of 30 patients, and by quantitative longitudinal assessments in 8 of 11 patients (SARA: -0.81/year). Explorative sample size calculations indicate that ≥48 patients per arm may suffice to demonstrate efficacy for interventions that reduce progression by 50%.

Interpretation: This study provides a deeper understanding of the disease, and paves the way toward large-scale natural history studies and treatment trials in COQ8A-ataxia. ANN NEUROL 2020;88:251-263.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ana.25751DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7877690PMC
August 2020

Novel Variants in Patients with Intellectual Disability.

Mol Syndromol 2019 Jul 3;10(4):195-201. Epub 2019 Apr 3.

Institute of Medical Genetics and Applied Genomics, Hertie Institute for Clinical Brain Research, Tübingen, Germany.

Intellectual disability (ID) occurs in approximately 1% of the population. Over the last years, broad sequencing approaches such as whole exome sequencing (WES) substantially contributed to the definition of the molecular defects underlying nonsyndromic ID. Pathogenic variants in , which encodes the human immunodeficiency virus type I enhancer binding protein 2, have recently been reported as a cause of ID, developmental delay, behavioral disorders, and dysmorphic features. HIVEP2 serves as a transcriptional factor regulating NF-ĸB and diverse genes that are essential in neural development. To date, only 8 patients with pathogenic de novo nonsense or frameshift variants and 1 patient with a pathogenic missense variant in have been reported. By WES, we identified 2 novel truncating variants, c.6609_6616delTGAGGGTC (p.Glu2204*) and c.6667C>T (p.Arg2223*), in 2 young adults presenting with developmental delay and mild ID without any dysmorphic features, systemic malformations, or behavioral issues.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000499060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6738162PMC
July 2019

variants in cause sporadic early-onset progressive sensorimotor neuropathy.

J Med Genet 2020 04 22;57(4):283-288. Epub 2019 Aug 22.

Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany

Background: Charcot-Marie-Tooth disease (CMT) is a clinically and genetically heterogeneous disorder of the peripheral nervous system. Biallelic variants in have been associated with autosomal-recessive hereditary motor and sensory neuropathy with agenesis of the corpus callosum (HMSN/ACC). We identified heterozygous de novo variants in in three unrelated patients with intermediate CMT.

Methods: We evaluated the clinical reports and electrophysiological data of three patients carrying de novo variants in identified by diagnostic trio exome sequencing. For functional characterisation of the identified variants, potassium influx of mutated KCC3 cotransporters was measured in oocytes.

Results: We identified two different de novo missense changes (p.Arg207His and p.Tyr679Cys) in in three unrelated individuals with early-onset progressive CMT. All presented with axonal/demyelinating sensorimotor neuropathy accompanied by spasticity in one patient. Cognition and brain MRI were normal. Modelling of the mutant KCC3 cotransporter in oocytes showed a significant reduction in potassium influx for both changes.

Conclusion: Our findings expand the genotypic and phenotypic spectrum associated with variants from autosomal-recessive HMSN/ACC to dominant-acting de novo variants causing a milder clinical presentation with early-onset neuropathy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/jmedgenet-2019-106273DOI Listing
April 2020

Correction: The ARID1B spectrum in 143 patients: from nonsyndromic intellectual disability to Coffin-Siris syndrome.

Genet Med 2019 Sep;21(9):2160-2161

University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands.

The original version of this Article contained an error in the spelling of the author Pleuntje J. van der Sluijs, which was incorrectly given as Eline (P. J.) van der Sluijs. This has now been corrected in both the PDF and HTML versions of the Article.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-018-0368-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6752317PMC
September 2019

The ARID1B spectrum in 143 patients: from nonsyndromic intellectual disability to Coffin-Siris syndrome.

Genet Med 2019 06 8;21(6):1295-1307. Epub 2018 Nov 8.

University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands.

Purpose: Pathogenic variants in ARID1B are one of the most frequent causes of intellectual disability (ID) as determined by large-scale exome sequencing studies. Most studies published thus far describe clinically diagnosed Coffin-Siris patients (ARID1B-CSS) and it is unclear whether these data are representative for patients identified through sequencing of unbiased ID cohorts (ARID1B-ID). We therefore sought to determine genotypic and phenotypic differences between ARID1B-ID and ARID1B-CSS. In parallel, we investigated the effect of different methods of phenotype reporting.

Methods: Clinicians entered clinical data in an extensive web-based survey.

Results: 79 ARID1B-CSS and 64 ARID1B-ID patients were included. CSS-associated dysmorphic features, such as thick eyebrows, long eyelashes, thick alae nasi, long and/or broad philtrum, small nails and small or absent fifth distal phalanx and hypertrichosis, were observed significantly more often (p < 0.001) in ARID1B-CSS patients. No other significant differences were identified.

Conclusion: There are only minor differences between ARID1B-ID and ARID1B-CSS patients. ARID1B-related disorders seem to consist of a spectrum, and patients should be managed similarly. We demonstrated that data collection methods without an explicit option to report the absence of a feature (such as most Human Phenotype Ontology-based methods) tended to underestimate gene-related features.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-018-0330-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6752273PMC
June 2019

Further evidence for complex inheritance of holoprosencephaly: Lessons learned from pre- and postnatal diagnostic testing in Germany.

Am J Med Genet C Semin Med Genet 2018 06;178(2):198-205

Center for Human Genetics Regensburg, Regensburg, Germany.

Holoprosencephaly (HPE) has been defined as a distinct clinical entity with characteristic facial gestalt, which may-or may not-be associated with the true brain malformation observed postmortem in autopsy or in pre- or postnatal imaging. Affected families mainly show autosomal dominant inheritance with markedly reduced penetrance and extremely broad clinical variability even between mutation carriers within the same families. We here present advances in prenatal imaging over the last years, increasing the proportion of individuals with HPE identified prenatally including milder HPE forms and more frequently allowing to detect more severe forms already in early gestation. We report the results of diagnostic genetic testing of 344 unrelated patients for HPE at our lab in Germany since the year 2000, which currently with the application of next generation sequencing (NGS) panel sequencing identifies causal mutations for about 31% (12/38) of unrelated individuals with normal chromosomes when compared to about 15% (46/306) using conventional Sanger sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA). More comprehensive genetic testing by our in house NGS panel sequencing of 10 HPE associated genes (MiSeq™ and NextSeq™500, Illumina, Inc., San Diego, CA) not only allowed to include genes with smaller contribution to the phenotype, but may also unravel additional low frequency or more common genetic variants potentially contributing to the observed large intrafamiliar variability and may ultimately guide our understanding of the individual clinical manifestation of this complex developmental disorder.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.c.31625DOI Listing
June 2018

First case report of malignant peritoneal mesothelioma and oral verrucous carcinoma in a patient with a germline PTEN mutation: a combination of extremely rare diseases with probable further implications.

BMC Med Genet 2018 08 15;19(1):144. Epub 2018 Aug 15.

Institute of Medical Genetics and Applied Genomics, University of Tübingen, Calwerstr. 7, 72076, Tübingen, Germany.

Background: The PTEN-hamartoma-tumor-syndrome (PHTS) is caused by germline mutations in Phosphatase and Tensin homolog (PTEN) and predisposes to the development of several typical malignancies. Whereas PTEN mutations have been implicated in the occurrence of malignant mesotheliomas, the genetic landscape of verrucous carcinomas (VC) is largely uncharted. Both VC and malignant peritoneal mesotheliomas (MPM) are exceedingly rare and a potential link between these malignancies and PHTS has never been reported.

Case Presentation: We here describe the clinical course of a PHTS patient who, in addition to a typical thyroid carcinoma at the age of 36 years, developed a highly-differentiated oral VC and an epithelioid MPM six years later. The patient with a history of occupational asbestos exposure underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for MPM. The clinical diagnosis of PHTS was consequently corroborated by a germline PTEN deletion. Sequencing of tumor tissue revealed a second hit in PTEN in the thyroid carcinoma and VC, confirmed by a PTEN loss and activation of the PI3K/AKT pathway in immunohistochemistry. Furthermore, additional somatic mutations in the thyroid carcinoma as well as in the VC were detected, whereas the genetics of MPM remained unrevealing.

Discussion And Conclusions: We here report the very unusual clinical course of a patient with rare tumors that have a germline mutation first hit in PTEN in common. Since this patient was exposed to asbestos and current evidence suggests molecular mechanisms that might render PHTS patients particularly susceptible to mesothelioma, we strongly recommend PHTS patients to avoid even minimal exposure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12881-018-0651-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6094911PMC
August 2018

Pathogenic variants in E3 ubiquitin ligase RLIM/RNF12 lead to a syndromic X-linked intellectual disability and behavior disorder.

Mol Psychiatry 2019 11 4;24(11):1748-1768. Epub 2018 May 4.

South Australian Clinical Genetics Service, SA Pathology (at Women's and Children's Hospital), North Adelaide, SA, 5006, Australia.

RLIM, also known as RNF12, is an X-linked E3 ubiquitin ligase acting as a negative regulator of LIM-domain containing transcription factors and participates in X-chromosome inactivation (XCI) in mice. We report the genetic and clinical findings of 84 individuals from nine unrelated families, eight of whom who have pathogenic variants in RLIM (RING finger LIM domain-interacting protein). A total of 40 affected males have X-linked intellectual disability (XLID) and variable behavioral anomalies with or without congenital malformations. In contrast, 44 heterozygous female carriers have normal cognition and behavior, but eight showed mild physical features. All RLIM variants identified are missense changes co-segregating with the phenotype and predicted to affect protein function. Eight of the nine altered amino acids are conserved and lie either within a domain essential for binding interacting proteins or in the C-terminal RING finger catalytic domain. In vitro experiments revealed that these amino acid changes in the RLIM RING finger impaired RLIM ubiquitin ligase activity. In vivo experiments in rlim mutant zebrafish showed that wild type RLIM rescued the zebrafish rlim phenotype, whereas the patient-specific missense RLIM variants failed to rescue the phenotype and thus represent likely severe loss-of-function mutations. In summary, we identified a spectrum of RLIM missense variants causing syndromic XLID and affecting the ubiquitin ligase activity of RLIM, suggesting that enzymatic activity of RLIM is required for normal development, cognition and behavior.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41380-018-0065-xDOI Listing
November 2019

Bainbridge-Ropers syndrome caused by loss-of-function variants in ASXL3: a recognizable condition.

Eur J Hum Genet 2017 02 30;25(2):183-191. Epub 2016 Nov 30.

Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany.

Truncating ASXL3 mutations were first identified in 2013 by Bainbridge et al. as a cause of syndromic intellectual disability in four children with similar phenotypes using whole-exome sequencing. The clinical features - postulated by Bainbridge et al. to be overlapping with Bohring-Opitz syndrome - were developmental delay, severe feeding difficulties, failure to thrive and neurological abnormalities. This condition was included in OMIM as 'Bainbridge-Ropers syndrome' (BRPS, #615485). To date, a total of nine individuals with BRPS have been published in the literature in four reports (Bainbridge et al., Dinwiddie et al, Srivastava et al. and Hori et al.). In this report, we describe six unrelated patients with newly diagnosed heterozygous de novo loss-of-function variants in ASXL3 and concordant clinical features: severe muscular hypotonia with feeding difficulties in infancy, significant motor delay, profound speech impairment, intellectual disability and a characteristic craniofacial phenotype (long face, arched eyebrows with mild synophrys, downslanting palpebral fissures, prominent columella, small alae nasi, high, narrow palate and relatively little facial expression). The majority of key features characteristic for Bohring-Opitz syndrome were absent in our patients (eg, the typical posture of arms, intrauterine growth retardation, microcephaly, trigonocephaly, typical facial gestalt with nevus flammeus of the forehead and exophthalmos). Therefore we emphasize that BRPS syndrome, caused by ASXL3 loss-of-function variants, is a clinically distinct intellectual disability syndrome with a recognizable phenotype distinguishable from that of Bohring-Opitz syndrome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ejhg.2016.165DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5255962PMC
February 2017

Microdeletions in 9q33.3-q34.11 in five patients with intellectual disability, microcephaly, and seizures of incomplete penetrance: is STXBP1 not the only causative gene?

Mol Cytogenet 2015 29;8:72. Epub 2015 Sep 29.

Institute of Human Genetics, University of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany.

Background: Most microdeletions involving chromosome sub-bands 9q33.3-9q34.11 to this point have been detected by analyses focused on STXBP1, a gene known to cause early infantile epileptic encephalopathy 4 and other seizure phenotypes. Loss-of-function mutations of STXBP1 have also been identified in some patients with intellectual disability without epilepsy. Consequently, STXBP1 is widely assumed to be the gene causing both seizures and intellectual disability in patients with 9q33.3-q34.11 microdeletions.

Results: We report five patients with overlapping microdeletions of chromosome 9q33.3-q34.11, four of them previously unreported. Their common clinical features include intellectual disability, psychomotor developmental delay with delayed or absent speech, muscular hypotonia, and strabismus. Microcephaly and short stature are each present in four of the patients. Two of the patients had seizures. De novo deletions range from 1.23 to 4.13 Mb, whereas the smallest deletion of 432 kb in patient 3 was inherited from her mother who is reported to have mild intellectual disability. The smallest region of overlap (SRO) of these deletions in 9q33.3 does not encompass STXBP1, but includes two genes that have not been previously associated with disease, RALGPS1 and GARNL3. Sequencing of the two SRO genes RALGPS1 and GARNL3 in at least 156 unrelated patients with mild to severe idiopathic intellectual disability detected no causative mutations. Gene expression analyses in our patients demonstrated significantly reduced expression levels of GARNL3, RALGPS1 and STXBP1 only in patients with deletions of the corresponding genes. Thus, reduced expression of STXBP1 was ruled out as a cause for seizures in our patient whose deletion did not encompass STXBP1.

Conclusions: We suggest that microdeletions of this region on chromosome 9q cause a clinical spectrum including intellectual disability, developmental delay especially concerning speech, microcephaly, short stature, mild dysmorphisms, strabismus, and seizures of incomplete penetrance, and may constitute a new contiguous gene deletion syndrome which cannot completely be explained by deletion of STXBP1.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13039-015-0178-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4587785PMC
September 2015

Interstitial duplication of chromosome region 1q25.1q25.3: report of a patient with mild cognitive deficits, tall stature and facial dysmorphisms.

Am J Med Genet A 2015 Mar;167A(3):653-6

Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany.

Isolated interstitial duplications of chromosome band 1q25 are apparently very rare; no patients with detailed molecular and clinical characterization of duplications restricted to this region have been published to date. We report on a 9-year-old girl with mild cognitive deficits, tall stature, macrocephaly and discrete dysmorphic features in whom a de novo interstitial 7.5 Mb duplication of 1q25.1q25.3 was detected by SNP array analysis (arr[hg19] 1q25.1q25.3(173,925,505-181,381,242)x3 dn). The duplicated region was inversely inserted into chromosome band 1q42.2: 46,XX,der(1)(pter→q42.2::q25.3→q25.1::q42.2→qter). Overexpression of one or several of the 87 genes in the duplicated interval was presumably the major causative factor for the clinical manifestations. Reports of additional patients with overlapping duplications will be needed to establish detailed karyotype-phenotype correlations and to gain a better understanding of the underlying pathomechanisms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.36943DOI Listing
March 2015

Next-generation sequencing in X-linked intellectual disability.

Eur J Hum Genet 2015 Nov 4;23(11):1513-8. Epub 2015 Feb 4.

Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany.

X-linked intellectual disability (XLID) is a genetically heterogeneous disorder with more than 100 genes known to date. Most genes are responsible for a small proportion of patients only, which has hitherto hampered the systematic screening of large patient cohorts. We performed targeted enrichment and next-generation sequencing of 107 XLID genes in a cohort of 150 male patients. Hundred patients had sporadic intellectual disability, and 50 patients had a family history suggestive of XLID. We also analysed a sporadic female patient with severe ID and epilepsy because she had strongly skewed X-inactivation. Target enrichment and high parallel sequencing allowed a diagnostic coverage of >10 reads for ~96% of all coding bases of the XLID genes at a mean coverage of 124 reads. We found 18 pathogenic variants in 13 XLID genes (AP1S2, ATRX, CUL4B, DLG3, IQSEC2, KDM5C, MED12, OPHN1, SLC9A6, SMC1A, UBE2A, UPF3B and ZDHHC9) among the 150 male patients. Thirteen pathogenic variants were present in the group of 50 familial patients (26%), and 5 pathogenic variants among the 100 sporadic patients (5%). Systematic gene dosage analysis for low coverage exons detected one pathogenic hemizygous deletion. An IQSEC2 nonsense variant was detected in the female ID patient, providing further evidence for a role of this gene in encephalopathy in females. Skewed X-inactivation was more frequently observed in mothers with pathogenic variants compared with those without known X-linked defects. The mutation rate in the cohort of sporadic patients corroborates previous estimates of 5-10% for X-chromosomal defects in male ID patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ejhg.2015.5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4613482PMC
November 2015

Severe presentation of WDR62 mutation: is there a role for modifying genetic factors?

Am J Med Genet A 2014 Sep 19;164A(9):2161-71. Epub 2014 May 19.

Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Germany.

Mutations in WDR62 are associated with primary microcephaly; however, they have been reported with wide phenotypic variability. We report on six individuals with novel WDR62 mutations who illustrate this variability and describe three in greater detail. Of the three, one lacks neuromotor development and has severe pachygyria on MRI, another has only delayed speech and motor development and moderate polymicrogyria, and the third has an intermediate phenotype. We observed a rare copy number change of unknown significance, a 17q25qter duplication, in the first severely affected individual. The 17q25 duplication included an interesting candidate gene, tubulin cofactor D (TBCD), crucial in microtubule assembly and disassembly. Sequencing of the non-duplicated allele showed a TBCD missense mutation, predicted to cause a deleterious p.Phe1121Val substitution. Sequencing of a cohort of five patients with WDR62 mutations, including one with an identical mutation and different phenotype, plus 12 individuals with diagnosis of microlissencephaly and another individual with mild intellectual disability (ID) and a 17q25 duplication, did not reveal TBCD mutations. However, immunostaining with tubulin antibodies of cells from patients with both WDR62 and TBCD mutation showed abnormal tubulin network when compared to controls and cells with only the WDR62 mutation. Therefore, we propose that genetic factors contribute to modify the severity of the WDR62 phenotype and, although based on suggestive evidence, TBCD could function as one of such factors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.36611DOI Listing
September 2014

Genome-wide UPD screening in patients with intellectual disability.

Eur J Hum Genet 2014 Oct 7;22(10):1233-5. Epub 2014 May 7.

1] Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany [2] Rare Disease Center, University of Tübingen, Tübingen, Germany.

Uniparental disomy (UPD) describes the inheritance of a pair of chromosomes from only one parent. It may occur as isodisomy, heterodisomy or a combination of both and may involve only chromosome segments. UPD can affect each chromosome. The incidence is estimated to be around 1:3500 in live births. Some parts of chromosomes are subject to 'parent-of-origin imprinting' and the phenotypic effect in UPD syndromes is mainly due to functional imbalance of imprinted genes. Isodisomy can result in mutation homozygosity in autosomal-recessive inherited diseases. UPD causes several well-defined imprinting syndromes associated with intellectual disability (ID). Although knowledge on frequency and size of UPDs in patients with unexplained ID remains largely unknown as no efficient genome-wide screening technique was available for detection of both isodisomic and heterodisomic UPDs. SNP microarrays have been proven to be capable to detect UPDs through Mendelian errors. The correct subclassification of UPD requires child-parent trio experiments. To further elucidate the role of UPD in patients with unexplained ID, we analyzed a total of 322 child-parent trios. We were not able to detect UPDs (isodisomies and heterodisomies) within our cohort spanning whole chromosomes or chromosomal segments. We conclude that UPD is rare in patients with unexplained ID.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ejhg.2014.63DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4169544PMC
October 2014

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

Mol Genet Genomic Med 2014 Mar 14;2(2):176-85. Epub 2014 Jan 14.

Department of Medicine, University of California San Diego San Diego, California.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mgg3.60DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3960060PMC
March 2014

Targeted high-throughput sequencing identifies a TARDBP mutation as a cause of early-onset FTD without motor neuron disease.

Neurobiol Aging 2014 May 29;35(5):1212.e1-5. Epub 2013 Oct 29.

Department of Neurology with Friedrich-Baur-Institute, Ludwig-Maximilians-University, Munich, Bavaria, Germany.

Targeted high-throughput sequencing of many amyotrophic lateral sclerosis (ALS) and fronto-temporal dementia (FTD) genes in parallel has the potential to reveal novel ALS- and/or FTD-phenotypes and to provide missing links on the ALS-FTD continuum. For example, although the 43-kDa transactive response DNA binding protein is the major pathologic hallmark linking ALS and FTD, mutations in the gene encoding 43-kDa transactive response DNA binding protein (TARDBP) have been appreciated only as a cause of ALS-phenotypes, but not yet of pure FTD. Thus, the genetic link is not yet well substantiated that TARDBP mutations can cause the full spectrum of the ALS-FTD continuum. High-throughput sequencing of 18 ALS and FTD genes in an index patient presenting with early-onset pure (behavioral) FTD and a positive family history for ALS revealed an established TARDBP mutation, A382T. This finding demonstrates that a TARDPB mutation can cause early-onset pure FTD without evidence for ALS even in advanced FTD disease stages. Moreover, it indicates that TARDPB screening might be considered even in young patients with "pure" neuropsychiatric disturbances and without evidence of neurodegenerative disease in the parental generation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neurobiolaging.2013.10.092DOI Listing
May 2014

12q24.33 deletion: report of a patient with intellectual disability and review of the literature.

Am J Med Genet A 2013 Jun 23;161A(6):1409-13. Epub 2013 Apr 23.

Institute of Human Genetics, University of Tuebingen, and University Children's Hospital, Tuebingen, Germany.

Deletions of chromosome band 12q24.33 are rare. We report on a 17-year-old male patient with intellectual disability but no major malformations or dysmorphic features in whom a de novo interstitial 660 kb deletion in 12q24.33 was detected by SNP array analysis. This deletion was secondary to a translocation t(12;14)(q24.3;q13)dn that also led to a small deletion in 14q21.1 and a small duplication in 2p23.1. The deletion overlaps with two previously published larger deletions in patients who suffered from intellectual disability, obesity, and polycystic kidney disease, indicating that haploinsufficiency of one or several of the genes in the deleted interval of the patient reported here causes intellectual deficits, but not obesity or renal problems. The 14 RefSeq genes that are harbored by this deletion include P2RX2, which had previously been proposed as a candidate gene for intellectual disability. Thus, the patient reported here broadens our knowledge of the phenotypic consequences of deletions in 12q24.33 and facilitates genotype-phenotype correlations for chromosome aberrations of this region.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.35877DOI Listing
June 2013

Xq22.3-q23 deletion including ACSL4 in a patient with intellectual disability.

Am J Med Genet A 2013 Apr 12;161A(4):860-4. Epub 2013 Mar 12.

Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany.

Mutations or deletions of ACSL4 (FACL4, OMIM 300157) are a rare cause of non-syndromic X-linked intellectual disability. We report on a 10-year-old male patient with moderate intellectual disability, sensorineural hearing loss, facial dysmorphism, pyloric stenosis, and intestinal obstruction in whom a de novo Xq22.3-q23 deletion was detected by SNP array analysis. The deleted 1.56 Mb interval harbored ACSL4 and eight neighboring genes (GUCY2F, NXT2, KCNE1L, TMEM164, MIR3978, AMMECR1, SNORD96B, and RGAG1). In contrast to previously reported patients with chromosome aberrations in the region of the AMME complex (Alport syndrome, intellectual disability, midface hypoplasia, and elliptocytosis, OMIM 300194), this deletion did not contain the Alport syndrome gene COL4A5, suggesting that loss of one or several of the other genes in this interval is responsible for the clinical problems. In summary, the patient reported here broadens our knowledge of the phenotypic consequences of deletions of chromosome region Xq22.3-q23 and provides further proof for ACSL4 as an X-linked intellectual disability gene.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.35778DOI Listing
April 2013

Interstitial 3p25.3-p26.1 deletion in a patient with intellectual disability.

Am J Med Genet A 2012 Oct 10;158A(10):2587-90. Epub 2012 Sep 10.

Institute of Human Genetics, University of Tuebingen, Germany.

Interstitial deletions of the short arm of chromosome 3 are rare. We report on a 3-year-old girl with intellectual disability, muscular hypotonia, strabismus, and facial anomalies in whom an interstitial 1.24 Mb deletion in 3p25.3-p26.1 was detected by SNP array analysis. The deleted region harbors 11 RefSeq genes including CAV3 and SRGAP3/MEGAP, which had been associated with muscle disorders and intellectual disability, respectively. The deletion overlaps with a slightly larger deletion in a girl with a more complex phenotype including congenital heart defect and epilepsy, which indicates that haploinsufficiency of one or several of the genes in the deleted interval causes intellectual deficits, but not heart defects or epilepsy. Thus, the patient broadens our knowledge of the phenotypic consequences of deletions in 3p25.3-p26.1 and facilitates genotype-phenotype correlations for chromosome aberrations of this region.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.35562DOI Listing
October 2012

Clinical significance of copy number variations in the 11p15.5 imprinting control regions: new cases and review of the literature.

J Med Genet 2012 Sep 26;49(9):547-53. Epub 2012 Jul 26.

Institute of Human Genetics, RWTH Aachen, Aachen, Germany.

Among the clusters of imprinted genes in humans, one of the most relevant regions involved in human growth is localised in 11p15. Opposite epigenetic and genomic disturbances in this chromosomal region contribute to two distinct imprinting disorders associated with disturbed growth, Silver-Russell and Beckwith-Wiedemann syndromes. Due to the complexity of the 11p15 imprinting regions and their interactions, the interpretation of the copy number variations in that region is complicated. The clinical outcome in case of microduplications or microdeletions is therefore influenced by the size, the breakpoint positions and the parental inheritance of the imbalance as well as by the imprinting status of the affected genes. Based on their own new cases and those from the literature, the authors give an overview on the genotype-phenotype correlation in chromosomal rearrangements in 11p15 as the basis for a directed genetic counselling. The detailed characterisation of patients and families helps to further delineate risk figures for syndromes associated with 11p15 disturbances. Furthermore, these cases provide us with profound insights in the complex regulation of the (imprinted) factors localised in 11p15.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/jmedgenet-2012-100967DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3439641PMC
September 2012

Interstitial 9q34.11-q34.13 deletion in a patient with severe intellectual disability, hydrocephalus, and cleft lip/palate.

Am J Med Genet A 2012 Jul 25;158A(7):1709-12. Epub 2012 May 25.

Institute of Human Genetics, University of Tuebingen, Tuebingen, Germany.

Interstitial deletions of chromosome bands 9q34.11-q34.13 are rare. We report on a 16-year-old female patient with severe intellectual disability, congenital hydrocephalus, cleft lip and palate, talipes equinovarus, epilepsy, kyphoscoliosis, convergent strabismus, severe short stature, dystrophy, and facial dysmorphic signs. Array analysis revealed a 3.7 Mb interstitial deletion in 9q34.11-q34.13. The deletion harbors more than 60 genes, including SPTAN1, DYT1/TOR1A, ABL1, ASS1, LAMC3, POMT1, DOLK, and GLE1, mutations in which have previously been associated with monogenic disorders. This is the first patient with a deletion of this size and position in 9q34.11-q34.13. Reports of additional patients with aberrations in this region will be needed to establish karyotype-phenotype correlations and to gain information on the contribution of individual genes for the clinical manifestations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.35398DOI Listing
July 2012

A 15q24 microdeletion in transient myeloproliferative disease (TMD) and acute megakaryoblastic leukaemia (AMKL) implicates PML and SUMO3 in the leukaemogenesis of TMD/AMKL.

Br J Haematol 2012 Apr 1;157(2):180-7. Epub 2012 Feb 1.

Department of Paediatric Oncology, Haematology and Immunology, University of Heidelberg Medical Centre, Heidelberg, Germany.

Transient myeloproliferative disorder (TMD) of the newborn and acute megakaryoblastic leukaemia (AMKL) in children with Down syndrome (DS) represent paradigmatic models of leukaemogenesis. Chromosome 21 gene dosage effects and truncating mutations of the X-chromosomal transcription factor GATA1 synergize to trigger TMD and AMKL in most patients. Here, we report the occurrence of TMD, which spontaneously remitted and later progressed to AMKL in a patient without DS but with a distinct dysmorphic syndrome. Genetic analysis of the leukaemic clone revealed somatic trisomy 21 and a truncating GATA1 mutation. The analysis of the patient's normal blood cell DNA on a genomic single nucleotide polymorphism (SNP) array revealed a de novo germ line 2·58 Mb 15q24 microdeletion including 41 known genes encompassing the tumour suppressor PML. Genomic context analysis of proteins encoded by genes that are included in the microdeletion, chromosome 21-encoded proteins and GATA1 suggests that the microdeletion may trigger leukaemogenesis by disturbing the balance of a hypothetical regulatory network of normal megakaryopoiesis involving PML, SUMO3 and GATA1. The 15q24 microdeletion may thus represent the first genetic hit to initiate leukaemogenesis and implicates PML and SUMO3 as novel components of the leukaemogenic network in TMD/AMKL.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1365-2141.2012.09028.xDOI Listing
April 2012

Phenotypic spectrum associated with CASK loss-of-function mutations.

J Med Genet 2011 Nov 27;48(11):741-51. Epub 2011 Sep 27.

Institute of Human Genetics, Heidelberg University, Heidelberg, Germany.

Background: Heterozygous mutations in the CASK gene in Xp11.4 have been shown to be associated with a distinct brain malformation phenotype in females, including disproportionate pontine and cerebellar hypoplasia.

Methods: The study characterised the CASK alteration in 20 new female patients by molecular karyotyping, fluorescence in situ hybridisation, sequencing, reverse transcriptase (RT) and/or quantitative real-time PCR. Clinical and brain imaging data of a total of 25 patients were reviewed.

Results: 11 submicroscopic copy number alterations, including nine deletions of ~11 kb to 4.5 Mb and two duplications, all covering (part of) CASK, four splice, four nonsense, and one 1 bp deletion are reported. These heterozygous CASK mutations most likely lead to a null allele. Brain imaging consistently showed diffuse brainstem and cerebellar hypoplasia with a dilated fourth ventricle, but of remarkably varying degrees. Analysis of 20 patients in this study, and five previously reported patients, revealed a core clinical phenotype comprising severe developmental delay/intellectual disability, severe postnatal microcephaly, often associated with growth retardation, (axial) hypotonia with or without hypertonia of extremities, optic nerve hypoplasia, and/or other eye abnormalities. A recognisable facial phenotype emerged, including prominent and broad nasal bridge and tip, small or short nose, long philtrum, small chin, and/or large ears.

Conclusions: These findings define the phenotypic spectrum associated with CASK loss-of-function mutations. The combination of developmental and brain imaging features together with mild facial dysmorphism is highly suggestive of this disorder and should prompt subsequent testing of the CASK gene.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/jmedgenet-2011-100218DOI Listing
November 2011

De novo MECP2 duplication in two females with random X-inactivation and moderate mental retardation.

Eur J Hum Genet 2011 May 16;19(5):507-12. Epub 2011 Feb 16.

Department of Medical Genetics, University of Tübingen, Tübingen, Germany.

Xq28 duplications including MECP2 are a well-known cause of severe mental retardation in males with seizures, muscular hypotonia, progressive spasticity, poor speech and recurrent infections that often lead to early death. Female carriers usually show a normal intellectual performance due to skewed X-inactivation (XCI). We report on two female patients with a de novo MECP2 duplication associated with moderate mental retardation. In both patients, the de novo duplication occurred on the paternal allele, and both patients show a random XCI, which can be assumed as the triggering factor for the phenotype. Furthermore, we describe the phenotype that might be restricted to unspecific mild-to -moderate mental retardation with neurological features in early adulthood.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ejhg.2010.226DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3083613PMC
May 2011

Homozygous loss of CHRNA7 on chromosome 15q13.3 causes severe encephalopathy with seizures and hypotonia.

Am J Med Genet A 2010 Nov;152A(11):2908-11

Department of Molecular Human Genetics, Institute of Human Genetics, Heidelberg University, Heidelberg, Germany.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.33692DOI Listing
November 2010

Mutations in MEF2C from the 5q14.3q15 microdeletion syndrome region are a frequent cause of severe mental retardation and diminish MECP2 and CDKL5 expression.

Hum Mutat 2010 Jun;31(6):722-33

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

The etiology of mental retardation remains elusive in the majority of cases. Microdeletions within chromosomal bands 5q14.3q15 were recently identified as a recurrent cause of severe mental retardation, epilepsy, muscular hypotonia, and variable minor anomalies. By molecular karyotyping we identified two novel 2.4- and 1.5-Mb microdeletions of this region in patients with a similar phenotype. Both deletions contained the MEF2C gene, which is located proximally to the previously defined smallest region of overlap. Nevertheless, due to its known role in neurogenesis, we considered MEF2C as a phenocritical candidate gene for the 5q14.3q15 microdeletion phenotype. We therefore performed mutational analysis in 362 patients with severe mental retardation and found two truncating and two missense de novo mutations in MEF2C, establishing defects in this transcription factor as a novel relatively frequent autosomal dominant cause of severe mental retardation accounting for as much as 1.1% of patients. In these patients we found diminished MECP2 and CDKL5 expression in vivo, and transcriptional reporter assays indicated that MEF2C mutations diminish synergistic transactivation of E-box promoters including that of MECP2 and CDKL5. We therefore conclude that the phenotypic overlap of patients with MEF2C mutations and atypical Rett syndrome is due to the involvement of a common pathway.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/humu.21253DOI Listing
June 2010

A transgenic mouse model of spinocerebellar ataxia type 3 resembling late disease onset and gender-specific instability of CAG repeats.

Neurobiol Dis 2010 Feb 20;37(2):284-93. Epub 2009 Aug 20.

Medical Genetics, University of Tuebingen, Tuebingen, Germany.

Spinocerebellar ataxia type 3 (SCA3), or Machado-Joseph disease (MJD), is caused by the expansion of a polyglutamine repeat in the ataxin-3 protein. We generated a mouse model of SCA3 expressing ataxin-3 with 148 CAG repeats under the control of the huntingtin promoter, resulting in ubiquitous expression throughout the whole brain. The model resembles many features of the disease in humans, including a late onset of symptoms and CAG repeat instability in transmission to offspring. We observed a biphasic progression of the disease, with hyperactivity during the first months and decline of motor coordination after about 1 year of age; however, intranuclear aggregates were not visible at this age. Few and small intranuclear aggregates appeared first at the age of 18 months, further supporting the claim that neuronal dysfunction precedes the formation of intranuclear aggregates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nbd.2009.08.002DOI Listing
February 2010

Molecular karyotyping of patients with unexplained mental retardation by SNP arrays: a multicenter study.

Hum Mutat 2009 Jul;30(7):1082-92

West Midlands Regional Genetics Laboratory and Clinical Genetics Unit, Birmingham Women's Hospital, Birmingham, United Kingdom.

Genomic microarrays have been implemented in the diagnosis of patients with unexplained mental retardation. This method, although revolutionizing cytogenetics, is still limited to the detection of rare de novo copy number variants (CNVs). Genome-wide single nucleotide polymorphism (SNP) microarrays provide high-resolution genotype as well as CNV information in a single experiment. We hypothesize that the widespread use of these microarray platforms can be exploited to greatly improve our understanding of the genetic causes of mental retardation and many other common disorders, while already providing a robust platform for routine diagnostics. Here we report a detailed validation of Affymetrix 500k SNP microarrays for the detection of CNVs associated to mental retardation. After this validation we applied the same platform in a multicenter study to test a total of 120 patients with unexplained mental retardation and their parents. Rare de novo CNVs were identified in 15% of cases, showing the importance of this approach in daily clinical practice. In addition, much more genomic variation was observed in these patients as well as their parents. We provide all of these data for the scientific community to jointly enhance our understanding of these genomic variants and their potential role in this common disorder.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/humu.21015DOI Listing
July 2009

Mapping translocation breakpoints by next-generation sequencing.

Genome Res 2008 Jul 7;18(7):1143-9. Epub 2008 Mar 7.

Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany.

Balanced chromosome rearrangements (BCRs) can cause genetic diseases by disrupting or inactivating specific genes, and the characterization of breakpoints in disease-associated BCRs has been instrumental in the molecular elucidation of a wide variety of genetic disorders. However, mapping chromosome breakpoints using traditional methods, such as in situ hybridization with fluorescent dye-labeled bacterial artificial chromosome clones (BAC-FISH), is rather laborious and time-consuming. In addition, the resolution of BAC-FISH is often insufficient to unequivocally identify the disrupted gene. To overcome these limitations, we have performed shotgun sequencing of flow-sorted derivative chromosomes using "next-generation" (Illumina/Solexa) multiplex sequencing-by-synthesis technology. As shown here for three different disease-associated BCRs, the coverage attained by this platform is sufficient to bridge the breakpoints by PCR amplification, and this procedure allows the determination of their exact nucleotide positions within a few weeks. Its implementation will greatly facilitate large-scale breakpoint mapping and gene finding in patients with disease-associated balanced translocations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1101/gr.076166.108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2493403PMC
July 2008