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1.
Brain ; 147(5): 1822-1836, 2024 May 03.
Article in English | MEDLINE | ID: mdl-38217872

ABSTRACT

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. Affected individuals show psychomotor delay and intellectual disability of variable severity, microcephaly, corpus callosum and white matter abnormalities, seizures, spasticity, short stature, muscle fatigability and weakness. Heterozygous parents do not show any conserved clinical pathology but report multiple incidences of intra-uterine fetal death, which were also observed in an eighth family included in this study. In vivo studies of abcc9 loss-of-function in zebrafish revealed an exacerbated motor response to pentylenetetrazole, a pro-convulsive drug, consistent with impaired neurodevelopment associated with an increased seizure susceptibility. Our findings define an ABCC9 loss-of-function-related phenotype, expanding the genotypic and phenotypic spectrum of AIMS and reveal novel human pathologies arising from KATP channel dysfunction.


Subject(s)
Intellectual Disability , Muscular Diseases , Sulfonylurea Receptors , Humans , Intellectual Disability/genetics , Female , Sulfonylurea Receptors/genetics , Male , Animals , Child , Muscular Diseases/genetics , Child, Preschool , Adolescent , Zebrafish , Loss of Function Mutation/genetics , Adult , Pedigree , Young Adult
2.
J Clin Invest ; 134(1)2024 Jan 02.
Article in English | MEDLINE | ID: mdl-37962958

ABSTRACT

Pre-mRNA splicing is a highly coordinated process. While its dysregulation has been linked to neurological deficits, our understanding of the underlying molecular and cellular mechanisms remains limited. We implicated pathogenic variants in U2AF2 and PRPF19, encoding spliceosome subunits in neurodevelopmental disorders (NDDs), by identifying 46 unrelated individuals with 23 de novo U2AF2 missense variants (including 7 recurrent variants in 30 individuals) and 6 individuals with de novo PRPF19 variants. Eight U2AF2 variants dysregulated splicing of a model substrate. Neuritogenesis was reduced in human neurons differentiated from human pluripotent stem cells carrying two U2AF2 hyper-recurrent variants. Neural loss of function (LoF) of the Drosophila orthologs U2af50 and Prp19 led to lethality, abnormal mushroom body (MB) patterning, and social deficits, which were differentially rescued by wild-type and mutant U2AF2 or PRPF19. Transcriptome profiling revealed splicing substrates or effectors (including Rbfox1, a third splicing factor), which rescued MB defects in U2af50-deficient flies. Upon reanalysis of negative clinical exomes followed by data sharing, we further identified 6 patients with NDD who carried RBFOX1 missense variants which, by in vitro testing, showed LoF. Our study implicates 3 splicing factors as NDD-causative genes and establishes a genetic network with hierarchy underlying human brain development and function.


Subject(s)
Neurodevelopmental Disorders , Spliceosomes , Humans , Spliceosomes/genetics , Gene Regulatory Networks , Neurodevelopmental Disorders/genetics , Mutation, Missense , RNA Splicing , RNA Splicing Factors/genetics , Nuclear Proteins/genetics , DNA Repair Enzymes/genetics
4.
PLoS One ; 18(9): e0290013, 2023.
Article in English | MEDLINE | ID: mdl-37672513

ABSTRACT

Colour agnosia is a disorder that impairs colour knowledge (naming, recognition) despite intact colour perception. Previously, we have identified the first and only-known family with hereditary developmental colour agnosia. The aim of the current study was to explore genomic regions and candidate genes that potentially cause this trait in this family. For three family members with developmental colour agnosia and three unaffected family members CGH-array analysis and exome sequencing was performed, and linkage analysis was carried out using DominantMapper, resulting in the identification of 19 cosegregating chromosomal regions. Whole exome sequencing resulted in 11 rare coding variants present in all affected family members with developmental colour agnosia and absent in unaffected members. These variants affected genes that have been implicated in neural processes and functions (CACNA2D4, DDX25, GRINA, MYO15A) or that have an indirect link to brain function, development or disease (MAML2, STAU1, TMED3, RABEPK), and a remaining group lacking brain expression or involved in non-neural traits (DEPDC7, OR1J1, OR8D4). Although this is an explorative study, the small set of candidate genes that could serve as a starting point for unravelling mechanisms of higher level cognitive functions and cortical specialization, and disorders therein such as developmental colour agnosia.


Subject(s)
Agnosia , Humans , Agnosia/genetics , Brain , Color , Cytoskeletal Proteins , RNA-Binding Proteins , Vesicular Transport Proteins
5.
Kidney Int ; 104(5): 995-1007, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37598857

ABSTRACT

Autosomal dominant polycystic kidney disease (ADPKD) resulting from pathogenic variants in PKD1 and PKD2 is the most common form of PKD, but other genetic causes tied to primary cilia function have been identified. Biallelic pathogenic variants in the serine/threonine kinase NEK8 cause a syndromic ciliopathy with extra-kidney manifestations. Here we identify NEK8 as a disease gene for ADPKD in 12 families. Clinical evaluation was combined with functional studies using fibroblasts and tubuloids from affected individuals. Nek8 knockout mouse kidney epithelial (IMCD3) cells transfected with wild type or variant NEK8 were further used to study ciliogenesis, ciliary trafficking, kinase function, and DNA damage responses. Twenty-one affected monoallelic individuals uniformly exhibited cystic kidney disease (mostly neonatal) without consistent extra-kidney manifestations. Recurrent de novo mutations of the NEK8 missense variant p.Arg45Trp, including mosaicism, were seen in ten families. Missense variants elsewhere within the kinase domain (p.Ile150Met and p.Lys157Gln) were also identified. Functional studies demonstrated normal localization of the NEK8 protein to the proximal cilium and no consistent cilia formation defects in patient-derived cells. NEK8-wild type protein and all variant forms of the protein expressed in Nek8 knockout IMCD3 cells were localized to cilia and supported ciliogenesis. However, Nek8 knockout IMCD3 cells expressing NEK8-p.Arg45Trp and NEK8-p.Lys157Gln showed significantly decreased polycystin-2 but normal ANKS6 localization in cilia. Moreover, p.Arg45Trp NEK8 exhibited reduced kinase activity in vitro. In patient derived tubuloids and IMCD3 cells expressing NEK8-p.Arg45Trp, DNA damage signaling was increased compared to healthy passage-matched controls. Thus, we propose a dominant-negative effect for specific heterozygous missense variants in the NEK8 kinase domain as a new cause of PKD.


Subject(s)
Polycystic Kidney Diseases , Polycystic Kidney, Autosomal Dominant , Animals , Humans , Infant, Newborn , Mice , Carrier Proteins/metabolism , Cilia/pathology , Kidney/metabolism , Mutation , NIMA-Related Kinases/genetics , NIMA-Related Kinases/metabolism , Polycystic Kidney Diseases/genetics , Polycystic Kidney, Autosomal Dominant/pathology , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Serine/genetics , Serine/metabolism , TRPP Cation Channels/genetics , TRPP Cation Channels/metabolism
6.
Hum Mol Genet ; 32(21): 3063-3077, 2023 10 17.
Article in English | MEDLINE | ID: mdl-37552066

ABSTRACT

Rab GTPases are important regulators of intracellular vesicular trafficking. RAB5C is a member of the Rab GTPase family that plays an important role in the endocytic pathway, membrane protein recycling and signaling. Here we report on 12 individuals with nine different heterozygous de novo variants in RAB5C. All but one patient with missense variants (n = 9) exhibited macrocephaly, combined with mild-to-moderate developmental delay. Patients with loss of function variants (n = 2) had an apparently more severe clinical phenotype with refractory epilepsy and intellectual disability but a normal head circumference. Four missense variants were investigated experimentally. In vitro biochemical studies revealed that all four variants were damaging, resulting in increased nucleotide exchange rate, attenuated responsivity to guanine exchange factors and heterogeneous effects on interactions with effector proteins. Studies in C. elegans confirmed that all four variants were damaging in vivo and showed defects in endocytic pathway function. The variant heterozygotes displayed phenotypes that were not observed in null heterozygotes, with two shown to be through a dominant negative mechanism. Expression of the human RAB5C variants in zebrafish embryos resulted in defective development, further underscoring the damaging effects of the RAB5C variants. Our combined bioinformatic, in vitro and in vivo experimental studies and clinical data support the association of RAB5C missense variants with a neurodevelopmental disorder characterized by macrocephaly and mild-to-moderate developmental delay through disruption of the endocytic pathway.


Subject(s)
Intellectual Disability , Megalencephaly , Neurodevelopmental Disorders , Animals , Humans , Child , Zebrafish/genetics , Zebrafish/metabolism , Caenorhabditis elegans/metabolism , Neurodevelopmental Disorders/genetics , Intellectual Disability/genetics , Phenotype , rab GTP-Binding Proteins/genetics , rab GTP-Binding Proteins/metabolism , Megalencephaly/genetics , Developmental Disabilities/genetics , Mutation, Missense/genetics , rab5 GTP-Binding Proteins/genetics , rab5 GTP-Binding Proteins/metabolism
7.
Gynecol Oncol ; 174: 239-246, 2023 07.
Article in English | MEDLINE | ID: mdl-37236033

ABSTRACT

OBJECTIVE: In the first part of this phase II study (NCT01164995), the combination of carboplatin and adavosertib (AZD1775) was shown to be safe and effective in patients with TP53 mutated platinum-resistant ovarian cancer (PROC). Here, we present the results of an additional safety and efficacy cohort and explore predictive biomarkers for resistance and response to this combination treatment. METHODS: This is a phase II, open-label, non-randomized study. Patients with TP53 mutated PROC received carboplatin AUC 5 mg/ ml·min intravenously and adavosertib 225 mg BID orally for 2.5 days in a 21-day cycle. The primary objective is to determine the efficacy and safety of carboplatin and adavosertib. Secondary objectives include progression-free survival (PFS), changes in circulating tumor cells (CTC) and exploration of genomic alterations. RESULTS: Thirty-two patients with a median age of 63 years (39-77 years) were enrolled and received treatment. Twenty-nine patients were evaluable for efficacy. Bone marrow toxicity, nausea and vomiting were the most common adverse events. Twelve patients showed partial response (PR) as best response, resulting in an objective ORR of 41% in the evaluable patients (95% CI: 23%-61%). The median PFS was 5.6 months (95% CI: 3.8-10.3). In patients with tumors harboring CCNE1 amplification, treatment efficacy was slightly but not significantly better. CONCLUSIONS: Adavosertib 225 mg BID for 2.5 days and carboplatin AUC 5 could be safely combined and showed anti-tumor efficacy in patients with PROC. However, bone marrow toxicity remains a point of concern, since this is the most common reason for dose reductions and dose delays.


Subject(s)
Ovarian Neoplasms , Female , Humans , Middle Aged , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Biomarkers , Carboplatin/therapeutic use , Carcinoma, Ovarian Epithelial/drug therapy , Cell Cycle Proteins/genetics , Disease-Free Survival , Ovarian Neoplasms/drug therapy , Ovarian Neoplasms/genetics , Ovarian Neoplasms/pathology , Protein-Tyrosine Kinases/antagonists & inhibitors , Tumor Suppressor Protein p53/genetics , Adult , Aged
8.
Mol Ecol Resour ; 23(6): 1288-1298, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37002710

ABSTRACT

Environmental integrons are ubiquitous in natural microbial communities, but they are mostly uncharacterized and their role remains elusive. Thus far, research has been hindered by methodological limitations. Here, we successfully used an innovative approach combining CRISPR-Cas9 enrichment with long-read nanopore sequencing to target, in a complex microbial community, a putative adaptive environmental integron, InOPS, and to unravel its complete structure and genetic context. A contig of 20 kb was recovered containing the complete integron from the microbial metagenome of oil-contaminated coastal sediments. InOPS exhibited typical integron features. The integrase, closely related to integrases of marine Desulfobacterota, possessed all the elements of a functional integron integrase. The gene cassettes harboured mostly unknown functions hampering inferences about their ecological importance. Moreover, the putative InOPS host, likely a hydrocarbonoclastic marine bacteria, raises questions as to the adaptive potential of InOPS in response to oil contamination. Finally, several mobile genetic elements were intertwined with InOPS highlighting likely genomic plasticity, and providing a source of genetic novelty. This case study showed the power of CRISPR-Cas9 enrichment to elucidate the structure and context of specific DNA regions for which only a short sequence is known. This method is a new tool for environmental microbiologists working with complex microbial communities to target low abundant, large or repetitive genetic structures that are difficult to obtain by classical metagenomics. More precisely, here, it offers new perspectives to comprehensively assess the eco-evolutionary significance of environmental integrons.


Les intégrons environnementaux sont omniprésents dans les communautés microbiennes naturelles, mais la plupart ne sont pas caractérisés et leur rôle reste obscur. A ce jour, les limitations méthodologiques ont restreint leur étude. Ici, nous avons utilisé avec succès une approche innovante, combinant l'enrichissement par CRISPR-Cas9 et le séquençage nanopore longs-fragments, pour cibler, dans une communauté microbienne complexe, un intégron environnemental potentiellement adaptatif, InOPS, et pour révéler sa structure complète et son contexte génétique. Un contig de 20 kb contenant l'intégron complet a été obtenu à partir du métagénome microbien de sédiments côtiers contaminés par du pétrole. InOPS présente les caractéristiques typiques d'un intégron. Son intégrase, proche des intégrases des Desulfobacterota marines, possède tous les éléments d'une intégrase d'intégron fonctionnelle. Les cassettes de gène ont des fonctions pour la plupart inconnues, ce qui empêche d'inférer leur importance écologique. De plus, l'hôte présumé d'InOPS, probablement une bactérie marine hydrocarbonoclaste, interroge sur le potentiel adaptatif d'InOPS en réponse à la contamination par le pétrole. En outre, la présence de plusieurs éléments génétiques mobiles dans le contig met en évidence une probable plasticité génomique qui pourrait être source de remaniements génétiques. Cette étude de cas a montré la puissance de l'enrichissement par CRISPR-Cas9 pour élucider la structure et le contexte de régions d'ADN spécifiques pour lesquelles seule une courte séquence est connue. Cette méthode fournit un nouvel outil aux microbiologistes environnementaux travaillant avec des communautés microbiennes complexes pour cibler des structures génétiques peu abondantes, larges ou répétées, qui sont difficiles à obtenir par métagénomique classique. Plus précisément, elle offre ici de nouvelles perspectives pour évaluer de manière exhaustive l'importance éco-évolutive des intégrons environnementaux.


Subject(s)
Integrons , Metagenomics , Integrons/genetics , CRISPR-Cas Systems , Bacteria/genetics , Integrases/genetics
9.
J Med Genet ; 60(3): 213-222, 2023 03.
Article in English | MEDLINE | ID: mdl-36690428

ABSTRACT

Histones hold significant interest in development and genetic disorders due to their critical roles in chromatin dynamics, influencing gene expression and genome integrity. These roles are linked to alterations of post-translational marks, which are generally concentrated in the histone tails. The machinery modifying or interpreting these marks, known as chromatin writers, erasers or readers, have been associated with many Mendelian disorders; however, it has been only recently that the histone proteins themselves have been directly implicated in Mendelian conditions. High throughput sequencing has recently identified mutations in genes encoding histone H1, H3 and H4, all causing neurodevelopmental disorders with clinical variability. Notably, many of the mutations lie outside of recognised post-translational modification-associated residues, suggesting disrupting the core functions of histones is a primary molecular mechanism underpinning these neurodevelopmental phenotypes. In this review, we describe the clinical and genetic features of histone-related disorders, focusing on the unique aspects associated with each histone gene family, while noting the commonalities which provide insight into the required roles for histone fidelity in brain development and functioning.


Subject(s)
Chromatin , Histones , Humans , Histones/metabolism , Protein Processing, Post-Translational , Mutation
10.
Am J Med Genet A ; 191(4): 1083-1088, 2023 04.
Article in English | MEDLINE | ID: mdl-36595458

ABSTRACT

A girl with a unilateral cleft lip, alveolus and palate, tooth agenesis, and mild dysmorphic features, without a specific underlying syndrome diagnosis, was genotypically characterized and phenotypically described. Cleft gene panel analysis, single-nucleotide polymorphism (SNP) array, whole genome sequencing (WGS), whole exome sequencing, and quantitative PCR (Q-PCR) analysis were used as diagnostic tests. SNP array revealed a maternal deletion at 16q24.1, encompassing the cleft candidate gene USP10. WES revealed an additional de novo Loss-of-Function variant (p.(Asn838fs)) in the Zinc-Finger-Homeobox-4 (ZFHX4) gene. Q-PCR was performed to explore the effect of the ZFHX4 variant and the deletion in 16q24.1. The mRNA expression of a selection of putative target genes involved in orofacial clefting showed a lowered expression of USP10 (52%), CRISPLD2 (31%), and CRISPLD1 (1%) compared to the control. IRF6 showed no difference in gene expression. This case supports ZFHX4 as a novel cleft gene and suggests USP10 may contribute to the etiology of orofacial clefts in humans.


Subject(s)
Cleft Lip , Cleft Palate , Female , Humans , Cleft Lip/genetics , Cleft Palate/genetics , Interferon Regulatory Factors/genetics , Polymorphism, Single Nucleotide , Ubiquitin Thiolesterase/genetics , Transcription Factors/genetics , Homeodomain Proteins/genetics
11.
Am J Hum Genet ; 110(1): 146-160, 2023 01 05.
Article in English | MEDLINE | ID: mdl-36608681

ABSTRACT

Neddylation has been implicated in various cellular pathways and in the pathophysiology of numerous diseases. We identified four individuals with bi-allelic variants in NAE1, which encodes the neddylation E1 enzyme. Pathogenicity was supported by decreased NAE1 abundance and overlapping clinical and cellular phenotypes. To delineate how cellular consequences of NAE1 deficiency would lead to the clinical phenotype, we focused primarily on the rarest phenotypic features, based on the assumption that these would best reflect the pathophysiology at stake. Two of the rarest features, neuronal loss and lymphopenia worsening during infections, suggest that NAE1 is required during cellular stress caused by infections to protect against cell death. In support, we found that stressing the proteasome system with MG132-requiring upregulation of neddylation to restore proteasomal function and proteasomal stress-led to increased cell death in fibroblasts of individuals with NAE1 genetic variants. Additionally, we found decreased lymphocyte counts after CD3/CD28 stimulation and decreased NF-κB translocation in individuals with NAE1 variants. The rarest phenotypic feature-delayed closure of the ischiopubic rami-correlated with significant downregulation of RUN2X and SOX9 expression in transcriptomic data of fibroblasts. Both genes are involved in the pathophysiology of ischiopubic hypoplasia. Thus, we show that NAE1 plays a major role in (skeletal) development and cellular homeostasis during stress. Our approach suggests that a focus on rare phenotypic features is able to provide significant pathophysiological insights in diseases caused by mutations in genes with pleiotropic effects.


Subject(s)
Intellectual Disability , Lymphopenia , Humans , NEDD8 Protein/genetics , NEDD8 Protein/metabolism , Signal Transduction/genetics , Intellectual Disability/genetics , NF-kappa B/metabolism , Proteasome Endopeptidase Complex/metabolism , Lymphopenia/genetics
12.
Eur J Hum Genet ; 31(2): 188-194, 2023 02.
Article in English | MEDLINE | ID: mdl-36336713

ABSTRACT

Cantu Syndrome (CS), [OMIM #239850] is characterized by hypertrichosis, osteochondrodysplasia, and cardiomegaly. CS is caused by gain-of-function (GOF) variants in the KCNJ8 or ABCC9 genes that encode pore-forming Kir6.1 and regulatory SUR2 subunits of ATP-sensitive potassium (KATP) channels. Many subjects with CS also present with the complication of lymphedema. A previously uncharacterized, heterozygous ABCC9 variant, p.(Leu1055_Glu1058delinsPro), termed indel1055, was identified in an individual diagnosed with idiopathic lymphedema. The variant was introduced into the equivalent position of rat SUR2A, and inside-out patches were used to characterize the KATP channels formed by Kir6.2 and WT or mutant SUR2A subunits coexpressed in Cosm6 cells. The indel1055 variant causes gain-of-function of the channel, with an increase of the IC50 for ATP inhibition compared to WT. Retrospective consideration of this individual reveals clear features of Cantu Syndrome. An additional heterozygous ABCC9 variant, p.(Ile419Thr), was identified in a second individual diagnosed with lymphedema. In this case, there were no additional features consistent with CS, and the properties of p.(Ile416Thr) (the corresponding mutation in rat SUR2A)--containing channels were not different from WT. This proof-of-principle study shows that idiopathic lymphedema may actually be a first presentation of otherwise unrecognized Cantu Syndrome, but molecular phenotyping of identified variants is necessary to confirm relevance.


Subject(s)
Hypertrichosis , Lymphedema , Osteochondrodysplasias , Rats , Animals , KATP Channels/genetics , Sulfonylurea Receptors/genetics , Osteochondrodysplasias/genetics , Hypertrichosis/genetics , Gain of Function Mutation , Retrospective Studies , Cardiomegaly/diagnosis , Adenosine Triphosphate
13.
J Infect Dis ; 226(2): 258-269, 2022 08 24.
Article in English | MEDLINE | ID: mdl-35429403

ABSTRACT

BACKGROUND: Recurrent respiratory syncytial virus (RSV) infection requiring hospitalization is rare and the underlying mechanism is unknown. We aimed to determine the role of CD14-mediated immunity in the pathogenesis of recurrent RSV infection. METHODS: We performed genotyping and longitudinal immunophenotyping of the first patient with a genetic CD14 deficiency who developed recurrent RSV infection. We analyzed gene expression profiles and interleukin (IL)-6 production by patient peripheral blood mononuclear cells in response to RSV pre- and post-fusion (F) protein. We generated CD14-deficient human nasal epithelial cells cultured at air-liquid interface (HNEC-ALI) of patient-derived cells and after CRISPR-based gene editing of control cells. We analyzed viral replication upon RSV infection. RESULTS: Sanger sequencing revealed a homozygous single-nucleotide deletion in CD14, resulting in absence of the CD14 protein in the index patient. In vitro, viral replication was similar in wild-type and CD14-/- HNEC-ALI. Loss of immune cell CD14 led to impaired cytokine and chemokine responses to RSV pre- and post-F protein, characterized by absence of IL-6 production. CONCLUSIONS: We report an association of recurrent RSV bronchiolitis with a loss of CD14 function in immune cells. Lack of CD14 function led to defective immune responses to RSV pre- and post-F protein without a change in viral replication.


Subject(s)
Respiratory Syncytial Virus Infections , Cytokines , Humans , Leukocytes, Mononuclear/metabolism , Lipopolysaccharide Receptors/deficiency , Respiratory Syncytial Virus, Human
14.
J Physiol ; 600(2): 299-312, 2022 01.
Article in English | MEDLINE | ID: mdl-34820842

ABSTRACT

ATP-sensitive potassium channels (KATP channels) are hetero-octameric nucleotide-gated ion channels that couple cellular metabolism to excitability in various tissues. In the heart, KATP channels are activated during ischaemia and potentially during adrenergic stimulation. In the vasculature, they are normally active at a low level, reducing vascular tone, but the ubiquitous nature of these channels leads to complex and poorly understood channelopathies as a result of gain- or loss-of-function mutations. Zebrafish (ZF) models of these channelopathies may provide insights to the link between molecular dysfunction and complex pathophysiology, but this requires understanding the tissue dependence of channel activity and subunit specificity. Thus far, direct analysis of ZF KATP expression and functional properties has only been performed in pancreatic ß-cells. Using a comprehensive combination of genetically modified fish, electrophysiology and gene expression analysis, we demonstrate that ZF cardiac myocytes (CM) and vascular smooth muscle (VSM) express functional KATP channels of similar subunit composition, structure and metabolic sensitivity to their mammalian counterparts. However, in contrast to mammalian cardiovascular KATP channels, ZF channels are insensitive to potassium channel opener drugs (pinacidil, minoxidil) in both chambers of the heart and in VSM. The results provide a first characterization of the molecular properties of fish KATP channels and validate the use of such genetically modified fish as models of human Cantú syndrome and ABCC9-related Intellectual Disability and Myopathy syndrome. KEY POINTS: Zebrafish cardiac myocytes (CM) and vascular smooth muscle (VSM) express functional KATP channels of similar subunit composition, structure and metabolic sensitivity to their mammalian counterparts. In contrast to mammalian cardiovascular KATP channels, zebrafish channels are insensitive to potassium channel opener drugs (pinacidil, minoxidil) in both chambers of the heart and in VSM. We provide a first characterization of the molecular properties of fish KATP channels and validate the use of such genetically modified fish as models of human Cantú syndrome and ABCC9-related Intellectual Disability and Myopathy syndrome.


Subject(s)
Hypertrichosis , KATP Channels , Animals , Humans , KATP Channels/genetics , Muscle, Smooth, Vascular , Myocytes, Cardiac , Sulfonylurea Receptors/genetics , Zebrafish
15.
Brain Commun ; 3(4): fcab256, 2021.
Article in English | MEDLINE | ID: mdl-34805998

ABSTRACT

The recent identification of NAA80/NAT6 as the enzyme that acetylates actins generated new insight into the process of post-translational actin modifications; however, the role of NAA80 in human physiology and pathology has not been clarified yet. We report two individuals from a single family harbouring a homozygous c.389T>C, p.(Leu130Pro) NAA80 genetic variant. Both individuals show progressive high-frequency sensorineural hearing loss, craniofacial dysmorphisms, developmental delay and mild proximal and axial muscle weakness. Based on the molecular structure, we predicted and confirmed the NAA80 c.389T>C, p.(Leu130Pro) variant to result in protein destabilization, causing severely decreased NAA80 protein availability. Concurrently, individuals exhibited a ∼50% decrease of actin acetylation. NAA80 individual derived fibroblasts and peripheral blood mononuclear cells showed increased migration, increased filopodia counts and increased levels of polymerized actin, in agreement with previous observations in NAA80 knock-out cells. Furthermore, the significant clinical overlap between NAA80 individuals and individuals with pathogenic variants in several actin subtypes reflects the general importance of controlled actin dynamics for the inner ear, brain and muscle. Taken together, we describe a new syndrome, caused by NAA80 genetic variants leading to decreased actin acetylation and disrupted associated molecular functions. Our work suggests a crucial role for NAA80-mediated actin dynamics in neuronal health, muscle health and hearing.

16.
BMJ Case Rep ; 14(7)2021 Jul 12.
Article in English | MEDLINE | ID: mdl-34253519

ABSTRACT

This case report of a young adult with Cantú syndrome (CS) illustrates a remarkable journey of learning how to cope with symptom management and emotional impact associated with a rare skin condition. We describe a 20-year-old woman with a CS-related mutation in ABCC9 resulting in clinical manifestations, including congenital hypertrichosis, facial dysmorphism and cardiomegaly. As of yet, no treatment is available for CS.Little is known about the impact of CS and similar (skin) conditions on the life of affected individuals, and about their needs and preferences in this regard. Hence, we describe the psychosocial implications our case had to deal with immediately after her diagnosis. In addition, we outline her significant progress in managing disease-associated features and emotional stress prompted by considerable personal development and an increase in confidence. This example shows that a normal lifestyle is achievable for (newly diagnosed) individuals despite suffering from CS or a related skin disorder.


Subject(s)
Hypertrichosis , Osteochondrodysplasias , Cardiomegaly , Female , Humans , Hypertrichosis/diagnosis , Hypertrichosis/genetics , Sulfonylurea Receptors , Young Adult
17.
Cancers (Basel) ; 13(10)2021 May 18.
Article in English | MEDLINE | ID: mdl-34069790

ABSTRACT

Adult granulosa cell tumor (AGCT) is a rare ovarian cancer subtype, with a peak incidence around 50-55 years. Although AGCT can occur in specific syndromes, a genetic predisposition for AGCT has not been identified. The aim of this study is to identify a genetic variant in families with AGCT patients, potentially contributing to tumor evolution. We identified four families, each including two women diagnosed with AGCT. Whole-genome sequencing was performed to identify overlapping germline variants or affected genes. Familial relationship was evaluated using genealogy and genomic analyses. Patient characteristics, medical (family) history, and pedigrees were collected. Findings were compared to a reference group of 33 unrelated AGCT patients. Mean age at diagnosis was 38 years (range from 17 to 60) versus 51 years in the reference group, and seven of eight patients were premenopausal. In two families, three first degree relatives were diagnosed with breast cancer. Furthermore, polycystic ovary syndrome (PCOS) and subfertility was reported in three families. Predicted deleterious variants in PIK3C2G, BMP5, and LRP2 were identified. In conclusion, AGCTs occur in families and could potentially be hereditary. In these families, the age of AGCT diagnosis is lower and cases of breast cancer, PCOS, and subfertility are present. We could not identify an overlapping genetic variant or affected locus that may explain a genetic predisposition for AGCT.

18.
Gynecol Oncol ; 162(2): 413-420, 2021 08.
Article in English | MEDLINE | ID: mdl-34083028

ABSTRACT

OBJECTIVE: Adult granulosa cell tumors (aGCTs) represent a rare, hormonally active subtype of ovarian cancer that has a tendency to relapse late and repeatedly. Current serum hormone markers are inaccurate in reflecting tumor burden in a subset of aGCT patients, indicating the need for a novel biomarker. We investigated the presence of circulating tumor DNA (ctDNA) harboring a FOXL2 or TERT promoter mutation in serial plasma samples of aGCT patients to determine its clinical value for monitoring disease. METHODS: In a national multicenter study, plasma samples (n = 110) were prospectively collected from 21 patients with primary (n = 3) or recurrent (n = 18) aGCT harboring a FOXL2 402C > G and/or TERT (C228T or C250T) promoter mutation. Circulating cell-free DNA was extracted and assessed for ctDNA containing one of either mutations using droplet digital PCR (ddPCR). Fractional abundance of FOXL2 mutant and TERT mutant ctDNA was correlated with clinical parameters. RESULTS: FOXL2 mutant ctDNA was found in plasma of 11 out of 14 patients (78.6%) with aGCT with a confirmed FOXL2 mutation. TERT C228T or TERT C250T mutant ctDNA was detected in plasma of 4 of 10 (40%) and 1 of 2 patients, respectively. Both FOXL2 mutant ctDNA and TERT promoter mutant ctDNA levels correlated with disease progression and treatment response in the majority of patients. CONCLUSIONS: FOXL2 mutant ctDNA was present in the majority of aGCT patients and TERT promoter mutant ctDNA has been identified in a smaller subset of patients. Both FOXL2 and TERT mutant ctDNA detection may have clinical value in disease monitoring.


Subject(s)
Biomarkers, Tumor/genetics , Forkhead Box Protein L2/genetics , Granulosa Cell Tumor/diagnosis , Neoplasm Recurrence, Local/diagnosis , Ovarian Neoplasms/diagnosis , Telomerase/genetics , Aged , Aged, 80 and over , Biomarkers, Tumor/blood , Circulating Tumor DNA/blood , Circulating Tumor DNA/genetics , Female , Granulosa Cell Tumor/blood , Granulosa Cell Tumor/genetics , Humans , Middle Aged , Mutation , Neoplasm Recurrence, Local/blood , Neoplasm Recurrence, Local/genetics , Ovarian Neoplasms/blood , Ovarian Neoplasms/genetics , Promoter Regions, Genetic/genetics , Prospective Studies
19.
Am J Med Genet A ; 185(8): 2434-2444, 2021 08.
Article in English | MEDLINE | ID: mdl-34056838

ABSTRACT

Cantú syndrome (CS) is caused by pathogenic variants in ABCC9 and KCNJ8 encoding the regulatory and pore-forming subunits of ATP-sensitive potassium (KATP ) channels. CS is characterized by congenital hypertrichosis, distinctive facial features, peripheral edema, and cardiac and neurodevelopmental abnormalities. Behavioral and cognitive issues have been self-reported by some CS individuals, but results of formal standardized investigations have not been published. To assess the cognitive profile, social functioning, and psychiatric symptoms in a large group of CS subjects systematically in a cross-sectional manner, we invited 35 individuals (1-69 years) with confirmed ABCC9 variants and their relatives to complete various commonly applied standardized age-related questionnaires, including the Kaufman brief intelligence test 2, the social responsiveness scale-2, and the Achenbach system of empirically based assessment. The majority of CS individuals demonstrated average verbal and nonverbal intelligence compared to the general population. Fifteen percent of cases showed social functioning strongly associated with a clinical diagnosis of autism spectrum disorder. Both externalizing and internalizing problems were also present in this cohort. In particular, anxiety, anxiety or attention deficit hyperactivity disorder, and autism spectrum behaviors were predominantly observed in the younger subjects in the cohort (≥25%), but this percentage decreased markedly in adults.


Subject(s)
Behavior , Cardiomegaly/diagnosis , Cognition , Hypertrichosis/diagnosis , Osteochondrodysplasias/diagnosis , Phenotype , Adolescent , Adult , Aged , Alleles , Cardiomegaly/genetics , Child , Child, Preschool , Emotions , Female , Genetic Association Studies , Genetic Predisposition to Disease , Humans , Hypertrichosis/genetics , Infant , Male , Middle Aged , Mutation , Osteochondrodysplasias/genetics , Sulfonylurea Receptors , Young Adult
20.
Orphanet J Rare Dis ; 16(1): 137, 2021 03 19.
Article in English | MEDLINE | ID: mdl-33741030

ABSTRACT

We report five patients with lung disease immuno-deficiency and chromosome breakage syndrome (LICS) but without recurrent infections and severe immunodeficiency. One patient had extended survival to 6.5 years. Hematopoietic stem-cell transplantation failed to cure another patient. Our findings suggest that the immunological abnormalities can be limited and do not fully explain the LICS phenotype.


Subject(s)
Hematopoietic Stem Cell Transplantation , Lung Diseases , Respiratory Distress Syndrome , Chromosome Breakage , Humans , Phenotype , Retrospective Studies
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