ORCID Profile
0000-0002-9604-5726
Current Organisation
KU Leuven
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Publisher: Elsevier BV
Date: 02-2010
Publisher: Elsevier BV
Date: 09-2005
DOI: 10.1086/444549
Publisher: Elsevier BV
Date: 08-2011
Publisher: Elsevier BV
Date: 02-2008
Publisher: Springer Science and Business Media LLC
Date: 05-12-2017
Publisher: Springer Science and Business Media LLC
Date: 02-2017
DOI: 10.1038/NG0217-317B
Publisher: BMJ
Date: 23-08-2006
Publisher: Springer Science and Business Media LLC
Date: 09-04-2008
DOI: 10.1038/EJHG.2008.66
Abstract: Mutations in the thyroid monocarboxylate transporter 8 gene (MCT8/SLC16A2) have been reported to result in X-linked mental retardation (XLMR) in patients with clinical features of the Allan-Herndon-Dudley syndrome (AHDS). We performed MCT8 mutation analysis including 13 XLMR families with LOD scores >2.0, 401 male MR sibships and 47 sporadic male patients with AHDS-like clinical features. One nonsense mutation (c.629insA) and two missense changes (c.1A>T and c.1673G>A) were identified. Consistent with previous reports on MCT8 missense changes, the patient with c.1673G>A showed elevated serum T3 level. The c.1A>T change in another patient affects a putative translation start codon, but the same change was present in his healthy brother. In addition normal serum T3 levels were present, suggesting that the c.1A>T (NM_006517) variation is not responsible for the MR phenotype but indicates that MCT8 translation likely starts with a methionine at position p.75. Moreover, we characterized a de novo translocation t(X )(q13.2 24) in a female patient with full blown AHDS clinical features including elevated serum T3 levels. The MCT8 gene was disrupted at the X-breakpoint. A complete loss of MCT8 expression was observed in a fibroblast cell-line derived from this patient because of unfavorable nonrandom X-inactivation. Taken together, these data indicate that MCT8 mutations are not common in non-AHDS MR patients yet they support that elevated serum T3 levels can be indicative for AHDS and that AHDS clinical features can be present in female MCT8 mutation carriers whenever there is unfavorable nonrandom X-inactivation.
Publisher: MDPI AG
Date: 18-03-2023
Abstract: Amyotrophic lateral sclerosis (ALS) is characterized by progressive loss of upper and lower motor neurons. In 10% of patients, the disorder runs in the family. Our aim was to study the impact of ALS-causing gene mutations on cerebral glucose metabolism. Between October 2010 and October 2022, 538 patients underwent genetic testing for mutations with strong evidence of causality for ALS and 18F-2-fluoro-2-deoxy-D-glucose-PET (FDG PET), at University Hospitals Leuven. We identified 48 C9orf72-ALS and 22 SOD1-ALS patients. After propensity score matching, two cohorts of 48 and 21 matched sporadic ALS patients, as well as 20 healthy controls were included. FDG PET images were assessed using a voxel-based and volume-of-interest approach. We observed widespread frontotemporal involvement in all ALS groups, in comparison to healthy controls. The degree of relative glucose metabolism in SOD1-ALS in motor and extra-motor regions did not differ significantly from matched sporadic ALS patients. In C9orf72-ALS, we found more pronounced hypometabolism in the peri-rolandic region and thalamus, and hypermetabolism in the medulla extending to the pons, in comparison to matched sporadic ALS patients. Our study revealed C9orf72-dependent differences in glucose metabolism in the peri-rolandic region, thalamus, and brainstem (i.e., medulla, extending to the pons) in relation to matched sporadic ALS patients.
Publisher: Springer Science and Business Media LLC
Date: 23-08-2016
DOI: 10.1038/MP.2016.135
Publisher: Wiley
Date: 13-03-2019
DOI: 10.1111/EPI.14683
Publisher: Hindawi Limited
Date: 11-2007
DOI: 10.1002/HUMU.20572
Abstract: We have recently reported a missense mutation in exon 4 of the tubulin alpha 1A (Tuba1a) gene in a hyperactive N-ethyl-N-nitrosourea (ENU) induced mouse mutant with abnormal lamination of the hippoc us. Neuroanatomical similarities between the Tuba1a mutant mouse and mice deficient for Doublecortin (Dcx) and Lis1 genes, and the well-established functional interaction between DCX and microtubules (MTs), led us to hypothesize that mutations in TUBA1A (TUBA3, previous symbol), the human homolog of Tuba1a, might give rise to cortical malformations. This hypothesis was subsequently confirmed by the identification of TUBA1A mutations in two patients with lissencephaly and pachygyria, respectively. Here we report additional TUBA1A mutations identified in six unrelated patients with a large spectrum of brain dysgeneses. The de novo occurrence was shown for all mutations, including one recurrent mutation (c.790C>T, p.R264C) detected in two patients, and two mutations that affect the same amino acid (c.1205G>A, p.R402H c.1204C>T, p.R402C) detected in two other patients. Retrospective examination of MR images suggests that patients with TUBA1A mutations share not only cortical dysgenesis, but also cerebellar, hippoc al, corpus callosum, and brainstem abnormalities. Interestingly, the specific high level of Tuba1a expression throughout the period of central nervous system (CNS) development, shown by in situ hybridization using mouse embryos, is in accordance with the brain-restricted developmental phenotype caused by TUBA1A mutations. All together, these results, in combination with previously reported data, strengthen the relevance of the known interaction between MTs and DCX, and highlight the importance of the MTs/DCX complex in the neuronal migration process.
Publisher: Springer Science and Business Media LLC
Date: 03-02-2015
DOI: 10.1038/MP.2014.193
Publisher: Oxford University Press (OUP)
Date: 24-06-2008
DOI: 10.1093/BRAIN/AWN113
Publisher: Oxford University Press (OUP)
Date: 06-10-2015
DOI: 10.1093/HMG/DDV414
Abstract: Next generation genomic technologies have made a significant contribution to the understanding of the genetic architecture of human neurodevelopmental disorders. Copy number variants (CNVs) play an important role in the genetics of intellectual disability (ID). For many CNVs, and copy number gains in particular, the responsible dosage-sensitive gene(s) have been hard to identify. We have collected 18 different interstitial microduplications and 1 microtriplication of Xq25. There were 15 affected in iduals from 6 different families and 13 singleton cases, 28 affected males in total. The critical overlapping region involved the STAG2 gene, which codes for a subunit of the cohesin complex that regulates cohesion of sister chromatids and gene transcription. We demonstrate that STAG2 is the dosage-sensitive gene within these CNVs, as gains of STAG2 mRNA and protein dysregulate disease-relevant neuronal gene networks in cells derived from affected in iduals. We also show that STAG2 gains result in increased expression of OPHN1, a known X-chromosome ID gene. Overall, we define a novel cohesinopathy due to copy number gain of Xq25 and STAG2 in particular.
Publisher: Elsevier BV
Date: 12-2004
DOI: 10.1086/426460
Publisher: Hindawi Limited
Date: 2007
DOI: 10.1002/HUMU.9482
Abstract: The EuroMRX family cohort consists of about 400 families with non-syndromic and 200 families with syndromic X-linked mental retardation (XLMR). After exclusion of Fragile X (Fra X) syndrome, probands from these families were tested for mutations in the coding sequence of 90 known and candidate XLMR genes. In total, 73 causative mutations were identified in 21 genes. For 42% of the families with obligate female carriers, the mental retardation phenotype could be explained by a mutation. There was no difference between families with (lod score >2) or without (lod score <2) significant linkage to the X chromosome. For families with two to five affected brothers (brother pair=BP families) only 17% of the MR could be explained. This is significantly lower (P=0.0067) than in families with obligate carrier females and indicates that the MR in about 40% (17/42) of the BP families is due to a single genetic defect on the X chromosome. The mutation frequency of XLMR genes in BP families is lower than can be expected on basis of the male to female ratio of patients with MR or observed recurrence risks. This might be explained by genetic risk factors on the X chromosome, resulting in a more complex etiology in a substantial portion of XLMR patients. The EuroMRX effort is the first attempt to unravel the molecular basis of cognitive dysfunction by large-scale approaches in a large patient cohort. Our results show that it is now possible to identify 42% of the genetic defects in non-syndromic and syndromic XLMR families with obligate female carriers.
Publisher: Springer Science and Business Media LLC
Date: 28-02-2007
DOI: 10.1007/S00439-007-0343-1
Abstract: Using high resolution X chromosome array-CGH we identified an interstitial microdeletion at Xp11.23 in three brothers with moderate to severe mental retardation (MR) without dysmorphic features. The extent of the deletion was subsequently delineated to about 50 kb by regular PCR and included only the SLC38A5 and FTSJ1 genes. The loss of the FTSJ1 MR gene in males is expected to result in the observed phenotype but the contribution of the deletion of the solute carrier SLC38A5 gene is less clear. Their mother also carries the deletion and completely inactivates the aberrant X chromosome. Interestingly, the distal breakpoint is situated within a 200 kb SSX repeat region that appears to stimulate recombination since subtle copy number changes often occur at this location and it is frequently involved in translocations in tumours. Since this apparent SSX unstable structure is flanked proximally by FTSJ1 and PQBP1, subtle deletions or duplications at this location would be expected to cause MR, as in our family. So far, we have screened a cohort of 300 patients but did not find additional aberrations at the FTSJ1 locus indicating that the frequency is likely to be low.
Publisher: Elsevier BV
Date: 11-2007
DOI: 10.1016/J.EJMG.2007.09.001
Abstract: The rapid advancement of high-resolution DNA copy number assessment methods revealed the significant contribution of submicroscopic genetic imbalances to abnormal phenotypes, including mental retardation. In order to detect submicroscopic genetic imbalances, we have screened 20 families with X-linked mental retardation (XLMR) using a chromosome X-specific array-MAPH platform with median resolution of 238kb. Among the 20 families, 18 were experimental, as they were not previously screened with any microarray method, and two were blind controls with known aberrations, as they were previously screened by array-CGH. This study presents the first clinical application of chromosome X-specific array-MAPH methodology. The screening of 20 affected males from 20 unrelated XLMR families resulted in the detection of an unknown deletion, spanning a region of 7-23kb. Family studies and population screening demonstrated that the detected deletion is an unknown rare copy number variant. One of the control s les, carrying approximately 6-Mb duplication was correctly identified, moreover it was found to be interrupted by a previously unknown 19kb region of normal copy number. The second control 50kb deletion was not identified, as this particular region was not covered by array-MAPH probes. This study demonstrates that the chromosome X-specific array-MAPH platform is a valuable tool for screening patients with XLMR, or other X-linked disorders, and emerges the need for introducing new high-resolution screening methods for the detection of genetic imbalances.
Publisher: Elsevier BV
Date: 05-2019
Publisher: Springer Science and Business Media LLC
Date: 07-08-2023
Publisher: Springer Science and Business Media LLC
Date: 23-04-2009
Publisher: Elsevier BV
Date: 08-2015
Publisher: Springer Science and Business Media LLC
Date: 26-01-2011
Publisher: SAGE Publications
Date: 05-2006
Abstract: Mandibuloacral dysplasia (MAD) is a rare autosomal recessive disorder characterized by skeletal abnormalities such as hypoplasia of the mandible and clavicles and acro-osteolysis. Other features include cutaneous atrophy and lipodystrophy. Two genetic loci are known for MAD: lamin A/C ( LMNA), encoding structural nuclear lamina proteins, and zinc metalloproteinase ( ZMPSTE24), a membrane-bound endoprotease involved in post-translational proteolytic cleavage of carboxy terminal residues of prelamin A to form mature lamin A. Mutational analysis of ZMPSTE24 in an additional patient with MAD and determination of functional activity of mutant ZMPSTE24 in a yeast growth arrest pheromone diffusion (halo) assay. We previously reported a Belgian woman with MAD who had ZMPSTE24 mutations and died of complications of chronic renal failure at the age of 27.5 years. We now report a 37-year-old Australian man with MAD who also had compound heterozygous mutations in the ZMPSTE24 gene, a null mutation, Phe361fsX379, and a missense mutation, Asn265Ser, which is partially active in the yeast complementation assay. He also developed end-stage renal disease and, despite receiving a cadaveric renal transplantation, died prematurely at the age of 37 years. Renal biopsies of both patients revealed focal segmental glomerulosclerosis, and the female patient had the collapsing variant. These observations suggest focal segmental glomerulosclerosis as a phenotypic manifestation in patients with ZMPSTE24 deficiency.
Publisher: Springer Science and Business Media LLC
Date: 19-04-2009
DOI: 10.1038/NG.367
Publisher: Springer Science and Business Media LLC
Date: 24-02-2009
DOI: 10.1038/MP.2009.14
Abstract: Mutations in the UPF3B gene, which encodes a protein involved in nonsense-mediated mRNA decay, have recently been described in four families with specific (Lujan-Fryns and FG syndromes), nonspecific X-linked mental retardation (XLMR) and autism. To further elucidate the contribution of UPF3B to mental retardation (MR), we screened its coding sequence in 397 families collected by the EuroMRX consortium. We identified one nonsense mutation, c.1081C>T .Arg361(*), in a family with nonspecific MR (MRX62) and two amino-acid substitutions in two other, unrelated families with MR and/or autism (c.1136G>A .Arg379His and c.1103G>A .Arg368Gln). Functional studies using lymphoblastoid cell lines from affected patients revealed that c.1081C>T mutation resulted in UPF3B mRNA degradation and consequent absence of the UPF3B protein. We also studied the subcellular localization of the wild-type and mutated UPF3B proteins in mouse primary hippoc al neurons. We did not detect any obvious difference in the localization between the wild-type UPF3B and the proteins carrying the two missense changes identified. However, we show that UPF3B is widely expressed in neurons and also presents in dendritic spines, which are essential structures for proper neurotransmission and thus learning and memory processes. Our results demonstrate that in addition to Lujan-Fryns and FG syndromes, UPF3B protein truncation mutations can cause also nonspecific XLMR. We also identify comorbidity of MR and autism in another family with UPF3B mutation. The neuronal localization pattern of the UPF3B protein and its function in mRNA surveillance suggests a potential function in the regulation of the expression and degradation of various mRNAs present at the synapse.
Publisher: Springer Science and Business Media LLC
Date: 05-11-2008
Publisher: Elsevier BV
Date: 02-2005
DOI: 10.1086/427563
Publisher: Springer Science and Business Media LLC
Date: 29-08-2016
DOI: 10.1038/NG.3661
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.DRUDIS.2016.10.011
Abstract: Decades of costly failures in translating drug candidates from preclinical disease models to human therapeutic use warrant reconsideration of the priority placed on animal models in biomedical research. Following an international workshop attended by experts from academia, government institutions, research funding bodies, and the corporate and non-governmental organisation (NGO) sectors, in this consensus report, we analyse, as case studies, five disease areas with major unmet needs for new treatments. In view of the scientifically driven transition towards a human pathways-based paradigm in toxicology, a similar paradigm shift appears to be justified in biomedical research. There is a pressing need for an approach that strategically implements advanced, human biology-based models and tools to understand disease pathways at multiple biological scales. We present recommendations to help achieve this.
No related grants have been discovered for Hilde Van Esch.