Publications by authors named "Haelst M"

Article Synopsis
  • The study investigated the prevalence of obesity and metabolic syndrome (MetS) in 103 adults with a specific genetic condition (microdeletion 22q11.2), finding significantly higher rates of both compared to the general population.* -
  • Among the participants, 32% had generalized obesity, 51.5% had abdominal obesity, and 33% had MetS, with these numbers contrasting sharply with population-based statistics.* -
  • Age was identified as a key factor influencing obesity and MetS outcomes, with older age correlating positively with higher BMI and waist circumference, particularly in individuals not using antipsychotic medications.*
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Neurodevelopmental disorder with or without autism or seizures (NEDAUS) is a neurodevelopmental disorder characterized by global developmental delay, speech delay, seizures, autistic features, and/or behavior abnormalities. It is caused by CUL3 (Cullin-3 ubiquitin ligase) haploinsufficiency. We collected clinical and molecular data from 26 individuals carrying pathogenic variants and variants of uncertain significance (VUS) in the CUL3 gene, including 20 previously unreported cases.

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Article Synopsis
  • ARID1A and ARID1B duplications are linked to Coffin-Siris syndrome, but ARID1B duplications have not been previously associated with a specific clinical phenotype until now.
  • A study analyzed 16 cases of ARID1A and 13 cases of ARID1B duplications, revealing that ARID1A duplications resulted in more severe symptoms, including intellectual disabilities and growth delays, while both groups displayed similar features.
  • The research identified unique DNA methylation patterns in ARID1A duplication patients, which differ from those with loss-of-function variants, suggesting the presence of a distinct clinical phenotype for both ARID1A and ARID1B duplications, indicating a new type of
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Background: Advances in understanding the etiology of intellectual disability (ID) has led to insights in potential (targeted) treatments and personalized care. Implications of ID on health are often complex and require a multidisciplinary approach. The aim was to investigate the reporting of genetic diagnoses in multidisciplinary ID care and to identify associated clinical and demographic factors.

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Over the last 75 years, the field of Human Genetics has developed enormously. One of the recent developments involves health-related direct-to-consumer genetic tests (DTC-GTs), through which consumers gain insight in their genetic information and personal health risks without involvement of a health care professional. The DTC-GT market is diverse and dynamic, testing for continuously changing combinations of traits and DNA-variants that can affect personal health and disease.

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CRISPR-Cas technology is a revolutionary technology to modify DNA sequences. Owing to its effectiveness and accuracy, CRISPR-Cas holds important promises for 'genetic therapy' for various hereditary disorders. CRISPR-Cas enables researchers to modify specific parts of the genome with unprecedented precision, which, in specific cases, can be applied to correct disease-causing DNA variants.

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Four European Reference Networks (ERN-EYE, ERKNet, Endo-ERN, ERN-ITHACA) have teamed up to establish a consensus statement and recommendations for Bardet-Biedl syndrome (BBS). BBS is an autosomal recessive ciliopathy with at least 26 genes identified to date. The clinical manifestations are pleiotropic, can be observed in utero and will progress with age.

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Obesity represents a major public health emergency worldwide, and its etiology is shaped by a complex interplay of environmental and genetic factors. Over the last decade, polygenic risk scores (PRS) have emerged as a promising tool to quantify an individual's genetic risk of obesity. The field of PRS in obesity genetics is rapidly evolving, shedding new lights on obesity mechanisms and holding promise for contributing to personalized prevention and treatment.

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Weiss-Kruszka Syndrome (WSKA) is caused by pathogenic variants in ZNF462 representing a rare autosomal dominant congenital anomaly syndrome. It is characterized by global developmental delay, hypotonia, feeding difficulties, and craniofacial abnormalities, documented in fewer than 30 patients. ZNF462, located on chromosome 9p31.

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Background: Rare genetic obesity commonly features early-onset obesity, hyperphagia, and therapy-resistance to lifestyle interventions. Pharmacotherapy is often required to treat hyperphagia and induce weight loss. We describe clinical outcomes of glucagon-like peptide-1 analogue liraglutide or naltrexone-bupropion treatment in adults with molecularly confirmed genetic obesity (MCGO) or highly suspected for genetic obesity without definite diagnosis (HSGO).

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Rare recurrent copy number variants (CNVs) at chromosomal loci 22q11.2 and 16p11.2 are genetic disorders with lifespan risk for neuropsychiatric disorders.

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Primary proteasomopathies have recently emerged as a new class of rare early-onset neurodevelopmental disorders (NDDs) caused by pathogenic variants in the PSMB1, PSMC1, PSMC3, or PSMD12 proteasome genes. Proteasomes are large multi-subunit protein complexes that maintain cellular protein homeostasis by clearing ubiquitin-tagged damaged, misfolded, or unnecessary proteins. In this study, we have identified PSMD11 as an additional proteasome gene in which pathogenic variation is associated with an NDD-causing proteasomopathy.

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Objective: Considering limited evidence on diagnostics of genetic obesity in adults, we evaluated phenotypes of adults with genetic obesity. Additionally, we assessed the applicability of Endocrine Society (ES) recommendations for genetic testing in pediatric obesity.

Methods: We compared clinical features, including age of onset of obesity and appetite, between adults with non-syndromic monogenic obesity (MO), adults with syndromic obesity (SO), and adults with common obesity (CO) as control patients.

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Chung-Jansen syndrome is a neurodevelopmental disorder characterized by intellectual disability, behavioral problems, obesity and dysmorphic features. It is caused by pathogenic variants in the PHIP gene that encodes for the Pleckstrin homology domain-interacting protein, which is part of an epigenetic modifier protein complex. Therefore, we hypothesized that PHIP haploinsufficiency may impact genome-wide DNA methylation (DNAm).

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Background And Objectives: Knowledge of young-onset Alzheimer disease in adults with Down syndrome has greatly improved clinical care. However, little is known about dementia in rare genetic neurodevelopmental disorders (RGNDs). In this review, a comprehensive overview is provided of reports on dementia and cognitive/adaptive trajectories in adults with RGNDs.

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The 16p11.2 deletion syndrome is a clinically heterogeneous disorder, characterized by developmental delay, intellectual disability, hyperphagia, obesity, macrocephaly and psychiatric problems. Cases with 16p11.

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Most patients with GNB1 encephalopathy have developmental delay and/or intellectual disability, brain anomalies and seizures. Recently, two cases with GNB1 encephalopathy caused by haploinsufficiency have been reported that also show a Prader-Willi-like phenotype of childhood hypotonia and severe obesity. Here we present three new cases from our expert centre for genetic obesity in which GNB1 truncating and splice variants, probably leading to haploinsufficiency, were identified.

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Pitt-Hopkins syndrome (PTHS) is a neurodevelopmental disorder caused by pathogenic variants in TCF4, leading to intellectual disability, specific morphological features, and autonomic nervous system dysfunction. Epigenetic dysregulation has been implicated in PTHS, prompting the investigation of a DNA methylation (DNAm) "episignature" specific to PTHS for diagnostic purposes and variant reclassification and functional insights into the molecular pathophysiology of this disorder. A cohort of 67 individuals with genetically confirmed PTHS and three individuals with intellectual disability and a variant of uncertain significance (VUS) in TCF4 were studied.

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Context: The melanocortin-4 receptor (MC4R) plays an important role in body weight regulation. Pathogenic MC4R variants are the most common cause of monogenic obesity.

Objective: We have identified 17 MC4R variants in adult and pediatric patients with obesity.

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Article Synopsis
  • The study investigates a neurodevelopmental disorder (-RD) caused by mutations in the MUNC18-1 gene, leading to symptoms like developmental delay and seizures, with varying severity among patients.
  • Using advanced techniques, researchers analyzed neurons derived from patients' stem cells, finding reduced levels of the MUNC18-1 protein, along with dysregulated proteins linked to synapse function and altered neuronal network activity.
  • The findings reveal common cellular traits across patients with -RD while also highlighting distinct phenotypic differences, suggesting varied underlying mechanisms of the disorder that could inform future research and therapy development.
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Verheij syndrome [VRJS; OMIM 615583] is a rare autosomal dominant neurodevelopmental disorder characterized by distinct clinical features, including growth retardation, intellectual disability, cardiac, and renal anomalies. VRJS is caused by deletions of chromosome 8q24.3 or pathogenic variants in the PUF60 gene.

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Rare recurrent copy number variants (CNVs) at chromosomal loci 22q11.2 and 16p11.2 are among the most common rare genetic disorders associated with significant risk for neuropsychiatric disorders across the lifespan.

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Loss-of-function mutation of ABCC9, the gene encoding the SUR2 subunit of ATP sensitive-potassium (KATP) channels, was recently associated with autosomal recessive ABCC9-related intellectual disability and myopathy syndrome (AIMS). Here we identify nine additional subjects, from seven unrelated families, harbouring different homozygous loss-of-function variants in ABCC9 and presenting with a conserved range of clinical features. All variants are predicted to result in severe truncations or in-frame deletions within SUR2, leading to the generation of non-functional SUR2-dependent KATP channels.

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Objective: The postsynaptic density protein of excitatory neurons PSD-95 is encoded by discs large MAGUK scaffold protein 4 (DLG4), de novo pathogenic variants of which lead to DLG4-related synaptopathy. The major clinical features are developmental delay, intellectual disability (ID), hypotonia, sleep disturbances, movement disorders, and epilepsy. Even though epilepsy is present in 50% of the individuals, it has not been investigated in detail.

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Purpose: Hao-Fountain syndrome (HAFOUS) is a neurodevelopmental disorder caused by pathogenic variants in USP7. HAFOUS is characterized by developmental delay, intellectual disability, speech delay, behavioral abnormalities, autism spectrum disorder, seizures, hypogonadism, and mild dysmorphic features. We investigated the phenotype of 18 participants with HAFOUS and performed DNA methylation (DNAm) analysis, aiming to generate a diagnostic biomarker.

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