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7 result(s) for "Kummeling Joost"
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Haploinsufficiency of the HIRA gene located in the 22q11 deletion syndrome region is associated with abnormal neurodevelopment and impaired dendritic outgrowth
The 22q11.2 deletion syndrome (22q11DS) is associated with a wide spectrum of cognitive and psychiatric symptoms. Despite the considerable work performed over the past 20 years, the genetic etiology of the neurodevelopmental phenotype remains speculative. Here, we report de novo heterozygous truncating variants in the HIRA (Histone cell cycle regulation defective, S. Cerevisiae, homolog of, A) gene associated with a neurodevelopmental disorder in two unrelated patients. HIRA is located within the commonly deleted region of the 22q11DS and encodes a histone chaperone that regulates neural progenitor proliferation and neurogenesis, and that belongs to the WD40 Repeat (WDR) protein family involved in brain development and neuronal connectivity. To address the specific impact of HIRA haploinsufficiency in the neurodevelopmental phenotype of 22q11DS, we combined Hira knock-down strategies in developing mouse primary hippocampal neurons, and the direct study of brains from heterozygous Hira+/− mice. Our in vitro analyses revealed that Hira gene is mostly expressed during neuritogenesis and early dendritogenesis stages in mouse total brain and in developing primary hippocampal neurons. Moreover, shRNA knock-down experiments showed that a twofold decrease of endogenous Hira expression level resulted in an impaired dendritic growth and branching in primary developing hippocampal neuronal cultures. In parallel, in vivo analyses demonstrated that Hira+/− mice displayed subtle neuroanatomical defects including a reduced size of the hippocampus, the fornix and the corpus callosum. Our results suggest that HIRA haploinsufficiency would likely contribute to the complex pathophysiology of the neurodevelopmental phenotype of 22q11DS by impairing key processes in neurogenesis and by causing neuroanatomical defects during cerebral development.
The impact of lockdown on young people with genetic neurodevelopmental disabilities: a study with the international participatory database GenIDA
Background Previous publications suggested that lockdown is likely to impact daily living issues of individuals with intellectual disabilities. The authors notably suspected an intensification of behavioural, eating and sleep problems. Methods To test these hypotheses, we conducted an international online survey about the impact of COVID-19-associated first lockdown on people with genetic neurodevelopmental disorders. This survey was carried out using GenIDA, an international participatory database collecting medical information on genetic neurodevelopmental disorders. Patients’ relatives took part in this online survey from 30/04/2020 to 09/06/2020. This survey adapted from GenIDA standard questionnaire requested information on diagnosis, lifestyle and was based on yes/no answers to questions regarding behaviour, diet, and sleep, in the 6-months period before lockdown and during lockdown. We also asked relatives to evaluate the intensity of these problems by severity level. Finally, relatives could freely comment in open fields on the medical and/or quality of life problems they had encountered during lockdown. Results In total 199 participants—144 children and 45 adults—with neurodevelopmental disorders (intellectual disability (79.4%) and/or autism spectrum disorder (21.6%)) of various genetic origins, with near-equal male/female (96/103) contribution and originating mainly from Europe and Northern America, were included. The average lockdown duration at time of the survey was 57 days. We did not find differences in the frequency of behavioural, eating and sleep problems before and during lockdown. Moreover, there was no apparent difference in the intensity of eating and sleep disorders between both periods. However, for persons with behavioural problems at both periods, relatives reported an increase in aggressivity, self-aggressivity, depressiveness, stereotypies, and restricted interests during lockdown, all of which might be interpreted as consequences of a lack of stimulation or a reaction to unexpected changes in daily habits. Conclusions Our results support previous studies that suggest that the negative impact of lockdown does not depend on the intellectual disability per se but on the associated comorbidities such as behavioural disorders. This study addresses the need for prevention of behavioural disturbance in the vulnerable population with genetic neurodevelopmental disabilities.
Expanding the phenotype of Kleefstra syndrome: speech, language and cognition in 103 individuals
ObjectivesSpeech and language impairments are core features of the neurodevelopmental genetic condition Kleefstra syndrome. Communication has not been systematically examined to guide intervention recommendations. We define the speech, language and cognitive phenotypic spectrum in a large cohort of individuals with Kleefstra syndrome.Method103 individuals with Kleefstra syndrome (40 males, median age 9.5 years, range 1–43 years) with pathogenic variants (52 9q34.3 deletions, 50 intragenic variants, 1 balanced translocation) were included. Speech, language and non-verbal communication were assessed. Cognitive, health and neurodevelopmental data were obtained.ResultsThe cognitive spectrum ranged from average intelligence (12/79, 15%) to severe intellectual disability (12/79, 15%). Language ability also ranged from average (10/90, 11%) to severely impaired (53/90, 59%). Speech disorders occurred in 48/49 (98%) verbal individuals and even occurred alongside average language and cognition. Developmental regression occurred in 11/80 (14%) individuals across motor, language and psychosocial domains. Communication aids, such as sign and speech-generating devices, were crucial for 61/103 (59%) individuals including those who were minimally verbal, had a speech disorder or following regression.ConclusionsThe speech, language and cognitive profile of Kleefstra syndrome is broad, ranging from severe impairment to average ability. Genotype and age do not explain the phenotypic variability. Early access to communication aids may improve communication and quality of life.
Characterization of SETD1A haploinsufficiency in humans and Drosophila defines a novel neurodevelopmental syndrome
Defects in histone methyltransferases (HMTs) are major contributing factors in neurodevelopmental disorders (NDDs). Heterozygous variants of SETD1A involved in histone H3 lysine 4 (H3K4) methylation were previously identified in individuals with schizophrenia. Here, we define the clinical features of the Mendelian syndrome associated with haploinsufficiency of SETD1A by investigating 15 predominantly pediatric individuals who all have de novo SETD1A variants. These individuals present with a core set of symptoms comprising global developmental delay and/or intellectual disability, subtle facial dysmorphisms, behavioral and psychiatric problems. We examined cellular phenotypes in three patient-derived lymphoblastoid cell lines with three variants: p.Gly535Alafs*12, c.4582-2_4582delAG, and p.Tyr1499Asp. These patient cell lines displayed DNA damage repair defects that were comparable to previously observed RNAi-mediated depletion of SETD1A. This suggested that these variants, including the p.Tyr1499Asp in the catalytic SET domain, behave as loss-of-function (LoF) alleles. Previous studies demonstrated a role for SETD1A in cell cycle control and differentiation. However, individuals with SETD1A variants do not show major structural brain defects or severe microcephaly, suggesting that defective proliferation and differentiation of neural progenitors is unlikely the single underlying cause of the disorder. We show here that the Drosophila melanogaster SETD1A orthologue is required in postmitotic neurons of the fly brain for normal memory, suggesting a role in post development neuronal function. Together, this study defines a neurodevelopmental disorder caused by dominant de novo LoF variants in SETD1A and further supports a role for H3K4 methyltransferases in the regulation of neuronal processes underlying normal cognitive functioning.
The impact of lockdown on young people with genetic neurodevelopmental disabilities: a study with the international participatory database GenIDA
Previous publications suggested that lockdown is likely to impact daily living issues of individuals with intellectual disabilities. The authors notably suspected an intensification of behavioural, eating and sleep problems. To test these hypotheses, we conducted an international online survey about the impact of COVID-19-associated first lockdown on people with genetic neurodevelopmental disorders. This survey was carried out using GenIDA, an international participatory database collecting medical information on genetic neurodevelopmental disorders. Patients' relatives took part in this online survey from 30/04/2020 to 09/06/2020. This survey adapted from GenIDA standard questionnaire requested information on diagnosis, lifestyle and was based on yes/no answers to questions regarding behaviour, diet, and sleep, in the 6-months period before lockdown and during lockdown. We also asked relatives to evaluate the intensity of these problems by severity level. Finally, relatives could freely comment in open fields on the medical and/or quality of life problems they had encountered during lockdown. In total 199 participants--144 children and 45 adults--with neurodevelopmental disorders (intellectual disability (79.4%) and/or autism spectrum disorder (21.6%)) of various genetic origins, with near-equal male/female (96/103) contribution and originating mainly from Europe and Northern America, were included. The average lockdown duration at time of the survey was 57 days. We did not find differences in the frequency of behavioural, eating and sleep problems before and during lockdown. Moreover, there was no apparent difference in the intensity of eating and sleep disorders between both periods. However, for persons with behavioural problems at both periods, relatives reported an increase in aggressivity, self-aggressivity, depressiveness, stereotypies, and restricted interests during lockdown, all of which might be interpreted as consequences of a lack of stimulation or a reaction to unexpected changes in daily habits. Our results support previous studies that suggest that the negative impact of lockdown does not depend on the intellectual disability per se but on the associated comorbidities such as behavioural disorders. This study addresses the need for prevention of behavioural disturbance in the vulnerable population with genetic neurodevelopmental disabilities.
Characterization of SETD1A haploinsufficiency in humans and Drosophila defines a novel neurodevelopmental syndrome
Defects in histone methyltransferases (HMTs) are major contributing factors in neurodevelopmental disorders (NDDs). Heterozygous variants of SETD1A involved in histone H3 lysine 4 (H3K4) methylation were previously identified in individuals with schizophrenia. Here, we define the clinical features of the Mendelian syndrome associated with haploinsufficiency of SETD1A by investigating 15 predominantly pediatric individuals who all have de novo SETD1A variants. These individuals present with a core set of symptoms comprising global developmental delay and/or intellectual disability, subtle facial dysmorphisms, behavioral and psychiatric problems. We examined cellular phenotypes in three patient derived lymphoblastoid cell lines with three variants: p.Gly535Alafs*12, c.4582-2_4582delAG, and p.Tyr1499Asp. These patient cell lines displayed DNA damage repair defects that were comparable to previously observed RNAi-mediated depletion of SETD1A. This suggested that these variants, including the p.Tyr1499Asp in the catalytic SET domain, behave as Loss-of-Function (LoF) alleles. Previous studies demonstrated a role for SETD1A in cell cycle control and differentiation. However, individuals with SETD1A variants do not show major structural brain defects or severe microcephaly, suggesting that defective proliferation and differentiation of neural progenitors is unlikely the single underlying cause of the disorder. We show here that the Drosophila Melanogaster SETD1A orthologue is required in postmitotic neurons of the fly brain for normal memory, suggesting a role in post development neuronal function. Together, this study defines a neurodevelopmental disorder caused by dominant de novo LoF variants in SETD1A and further supports a role for H3K4 methyltransferases in the regulation of neuronal processes underlying normal cognitive functioning.
Exploratory analysis of the effect of mirabegron on urodynamic sensation parameters and urethral pressure variations
Introduction and hypothesisUrethral instability (URI) has in the past been defined by the International Continence Society (ICS), but was excluded from ICS terminology and definitions shortly after because of a lack of consensus about the clinical importance of this phenomenon. Recently, interest in URI and its possible role in overactive bladder (OAB) increased again. In the last decade, a beta 3 adrenoreceptor agonist (mirabegron) was approved for the treatment of OAB. The effect of mirabegron on urethral pressure during filling cystometry is unknown. The aim of this study was to assess the influence of mirabegron on urethral pressure variations during urodynamic investigation and the association of symptoms and voiding diary data before and during treatment.MethodsThis prospective study included 51 consecutive adult female patients, referred with OAB. Patients were evaluated using a voiding diary, two validated questionnaires and two urodynamic investigations, one before and one after 6 weeks of treatment with mirabegron. URI was defined as an urethral pressure drop exceeding 30 cmH2O during filling cystometry.ResultsThe prevalence of URI was 31% at initial urodynamic investigation, and 19% at second investigation. URI is more common than DO with 18% prevalence at initial evaluation. Treatment with mirabegron resulted in significant changes in symptoms and urodynamic sensory markers in patients with URI.ConclusionUrethral pressure variations are significantly reduced by treatment with mirabegron in patients with URI. URI seems to have a predictive value in treatment choices for OAB. Future research should elucidate this.