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1.
PLoS One ; 14(5): e0217477, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31136621

RESUMO

INTRODUCTION: Anorectal malformations (ARM) are rare congenital malformations, resulting from disturbed hindgut development. A genetic etiology has been suggested, but evidence for the involvement of specific genes is scarce. We evaluated the contribution of rare and low-frequency coding variants in ARM etiology, assuming a multifactorial model. METHODS: We analyzed 568 Caucasian ARM patients and 1,860 population-based controls using the Illumina HumanExome Beadchip array, which contains >240,000 rare and low-frequency coding variants. GenomeStudio clustering and calling was followed by re-calling of 'no-calls' using zCall for patients and controls simultaneously. Single variant and gene-based analyses were performed to identify statistically significant associations, applying Bonferroni correction. Following an extra quality control step, candidate variants were selected for validation using Sanger sequencing. RESULTS: When we applied a MAF of ≥1.0%, no variants or genes showed statistically significant associations with ARM. Using a MAF cut-off at 0.4%, 13 variants initially reached statistical significance, but had to be discarded upon further inspection: ten variants represented calling errors of the software, while the minor alleles of the remaining three variants were not confirmed by Sanger sequencing. CONCLUSION: Our results show that rare and low-frequency coding variants with large effect sizes, present on the exome chip do not contribute to ARM etiology.

2.
Eur J Hum Genet ; 27(4): 582-593, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30622326

RESUMO

The Integrator complex subunit 1 (INTS1) is a component of the integrator complex that comprises 14 subunits and associates with RPB1 to catalyze endonucleolytic cleavage of nascent snRNAs and assist RNA polymerase II in promoter-proximal pause-release on protein-coding genes. We present five patients, including two sib pairs, with biallelic sequence variants in INTS1. The patients manifested absent or severely limited speech, an abnormal gait, hypotonia and cataracts. Exome sequencing revealed biallelic variants in INTS1 in all patients. One sib pair demonstrated a missense variant, p.(Arg77Cys), and a frameshift variant, p.(Arg1800Profs*20), another sib pair had a homozygous missense variant, p.(Pro1874Leu), and the fifth patient had a frameshift variant, p.(Leu1764Cysfs*16) and a missense variant, p.(Leu2164Pro). We also report additional clinical data on three previously described individuals with a homozygous, loss of function variant, p.(Ser1784*) in INTS1 that shared cognitive delays, cataracts and dysmorphic features with these patients. Several of the variants affected the protein C-terminus and preliminary modeling showed that the p.(Pro1874Leu) and p.(Leu2164Pro) variants may interfere with INTS1 helix folding. In view of the cataracts observed, we performed in-situ hybridization and demonstrated expression of ints1 in the zebrafish eye. We used Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 to make larvae with biallelic insertion/deletion (indel) variants in ints1. The mutant larvae developed typically through gastrulation, but sections of the eye showed abnormal lens development. The distinctive phenotype associated with biallelic variants in INTS1 points to dysfunction of the integrator complex as a mechanism for intellectual disability, eye defects and craniofacial anomalies.

3.
Neurology ; 92(2): e96-e107, 2019 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-30541864

RESUMO

OBJECTIVE: To delineate the epileptology, a key part of the SYNGAP1 phenotypic spectrum, in a large patient cohort. METHODS: Patients were recruited via investigators' practices or social media. We included patients with (likely) pathogenic SYNGAP1 variants or chromosome 6p21.32 microdeletions incorporating SYNGAP1. We analyzed patients' phenotypes using a standardized epilepsy questionnaire, medical records, EEG, MRI, and seizure videos. RESULTS: We included 57 patients (53% male, median age 8 years) with SYNGAP1 mutations (n = 53) or microdeletions (n = 4). Of the 57 patients, 56 had epilepsy: generalized in 55, with focal seizures in 7 and infantile spasms in 1. Median seizure onset age was 2 years. A novel type of drop attack was identified comprising eyelid myoclonia evolving to a myoclonic-atonic (n = 5) or atonic (n = 8) seizure. Seizure types included eyelid myoclonia with absences (65%), myoclonic seizures (34%), atypical (20%) and typical (18%) absences, and atonic seizures (14%), triggered by eating in 25%. Developmental delay preceded seizure onset in 54 of 56 (96%) patients for whom early developmental history was available. Developmental plateauing or regression occurred with seizures in 56 in the context of a developmental and epileptic encephalopathy (DEE). Fifty-five of 57 patients had intellectual disability, which was moderate to severe in 50. Other common features included behavioral problems (73%); high pain threshold (72%); eating problems, including oral aversion (68%); hypotonia (67%); sleeping problems (62%); autism spectrum disorder (54%); and ataxia or gait abnormalities (51%). CONCLUSIONS: SYNGAP1 mutations cause a generalized DEE with a distinctive syndrome combining epilepsy with eyelid myoclonia with absences and myoclonic-atonic seizures, as well as a predilection to seizures triggered by eating.

4.
Am J Hum Genet ; 104(1): 164-178, 2019 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-30580808

RESUMO

SMARCC2 (BAF170) is one of the invariable core subunits of the ATP-dependent chromatin remodeling BAF (BRG1-associated factor) complex and plays a crucial role in embryogenesis and corticogenesis. Pathogenic variants in genes encoding other components of the BAF complex have been associated with intellectual disability syndromes. Despite its significant biological role, variants in SMARCC2 have not been directly associated with human disease previously. Using whole-exome sequencing and a web-based gene-matching program, we identified 15 individuals with variable degrees of neurodevelopmental delay and growth retardation harboring one of 13 heterozygous variants in SMARCC2, most of them novel and proven de novo. The clinical presentation overlaps with intellectual disability syndromes associated with other BAF subunits, such as Coffin-Siris and Nicolaides-Baraitser syndromes and includes prominent speech impairment, hypotonia, feeding difficulties, behavioral abnormalities, and dysmorphic features such as hypertrichosis, thick eyebrows, thin upper lip vermilion, and upturned nose. Nine out of the fifteen individuals harbor variants in the highly conserved SMARCC2 DNA-interacting domains (SANT and SWIRM) and present with a more severe phenotype. Two of these individuals present cardiac abnormalities. Transcriptomic analysis of fibroblasts from affected individuals highlights a group of differentially expressed genes with possible roles in regulation of neuronal development and function, namely H19, SCRG1, RELN, and CACNB4. Our findings suggest a novel SMARCC2-related syndrome that overlaps with neurodevelopmental disorders associated with variants in BAF-complex subunits.

5.
Ned Tijdschr Geneeskd ; 1622018 11 26.
Artigo em Holandês | MEDLINE | ID: mdl-30500128

RESUMO

Whole Exome Sequencing (WES) is becoming a standard diagnostic tool for patients who potentially suffer from an underlying monogenic condition. This is illustrated by the use of WES panels for specific medical conditions; in such instances, analysis is focused on a subset of genes that can be implicated in the pathogenesis of a condition such as epilepsy, intellectual disability, cardiomyopathy, etc. Physicians requesting WES diagnostics should be informed about the possibilities, limitations and pitfalls of this test. Here, we give a short introduction on the background of WES and also explain its potential in today's practice. In addition, we will discuss the limitations of WES and the WES classification system, which is used to indicate the pathogenic character of identified gene variants, will be further explained. We expect that WES will soon become a standard diagnostic tool for physicians from many disciplines.

6.
Nephron ; 140(3): 203-210, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30212818

RESUMO

BACKGROUND: Alport syndrome is a rare inheritable kidney disease frequently leading to end-stage kidney disease in young adults. Patients could benefit from early recognition of the disease. In several children with Alport syndrome, a parent was noticed to have renal symptoms attributed to another renal disease. AIM: To review the renal history of the closest family members of a cohort of pediatric patients with genetically proven Alport syndrome. METHODS: The medical records of all children with genetically proven Alport syndrome identified at our pediatric nephrology department in the last 20 years were reviewed, with focus on the medical history of affected parents. RESULTS: Twenty-three children with Alport syndrome from 21 different families were identified. Eight of 21 probands had family member(s) with renal symptoms attributed to other diseases. In these, a type IV collagen mutation was determined only after the manifestation of Alport syndrome in their child. One proband presented atypically with acute membrano-proliferative glomerulo-nephritis. Only 3 out of 8 probands with a known family history of Alport syndrome had been intentionally screened for this disease. A COL4A5 mutation was found in 18 probands, COL4A3 in 2, and COL4A4 in 1. Each family showed private mutations; 17 out of 21 mutations were novel. CONCLUSIONS: Atypical presentation of Alport syndrome was quite common in mothers of our pediatric patients. To enable earlier diagnosis of Alport syndrome, nephrologists should look for a positive diagnosis in any patient with persistent renal symptoms, especially if there is a positive family history of (any) renal disease.

7.
Gastroenterology ; 155(1): 118-129.e6, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29601828

RESUMO

BACKGROUND & AIMS: Hirschsprung disease (HSCR) is an inherited congenital disorder characterized by absence of enteric ganglia in the distal part of the gut. Variants in ret proto-oncogene (RET) have been associated with up to 50% of familial and 35% of sporadic cases. We searched for variants that affect disease risk in a large, multigenerational family with history of HSCR in a linkage region previously associated with the disease (4q31.3-q32.3) and exome wide. METHODS: We performed exome sequencing analyses of a family in the Netherlands with 5 members diagnosed with HSCR and 2 members diagnosed with functional constipation. We initially focused on variants in genes located in 4q31.3-q32.3; however, we also performed an exome-wide analysis in which known HSCR or HSCR-associated gene variants predicted to be deleterious were prioritized for further analysis. Candidate genes were expressed in HEK293, COS-7, and Neuro-2a cells and analyzed by luciferase and immunoblot assays. Morpholinos were designed to target exons of candidate genes and injected into 1-cell stage zebrafish embryos. Embryos were allowed to develop and stained for enteric neurons. RESULTS: Within the linkage region, we identified 1 putative splice variant in the lipopolysaccharide responsive beige-like anchor protein gene (LRBA). Functional assays could not confirm its predicted effect on messenger RNA splicing or on expression of the mab-21 like 2 gene (MAB21L2), which is embedded in LRBA. Zebrafish that developed following injection of the lrba morpholino had a shortened body axis and subtle gut morphological defects, but no significant reduction in number of enteric neurons compared with controls. Outside the linkage region, members of 1 branch of the family carried a previously unidentified RET variant or an in-frame deletion in the glial cell line derived neurotrophic factor gene (GDNF), which encodes a ligand of RET. This deletion was located 6 base pairs before the last codon. We also found variants in the Indian hedgehog gene (IHH) and its mediator, the transcription factor GLI family zinc finger 3 (GLI3). When expressed in cells, the RET-P399L variant disrupted protein glycosylation and had altered phosphorylation following activation by GDNF. The deletion in GDNF prevented secretion of its gene product, reducing RET activation, and the IHH-Q51K variant reduced expression of the transcription factor GLI1. Injection of morpholinos that target ihh reduced the number of enteric neurons to 13% ± 1.4% of control zebrafish. CONCLUSIONS: In a study of a large family with history of HSCR, we identified variants in LRBA, RET, the gene encoding the RET ligand (GDNF), IHH, and a gene encoding a mediator of IHH signaling (GLI3). These variants altered functions of the gene products when expressed in cells and knockout of ihh reduced the number of enteric neurons in the zebrafish gut.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Fator Neurotrófico Derivado de Linhagem de Célula Glial/genética , Proteínas Hedgehog/genética , Doença de Hirschsprung/genética , Proteínas do Tecido Nervoso/genética , Proteínas Proto-Oncogênicas c-ret/genética , Proteína Gli3 com Dedos de Zinco/genética , Animais , Células COS , Cercopithecus aethiops , Família , Feminino , Predisposição Genética para Doença , Variação Genética , Células HEK293 , Humanos , Masculino , Morfolinos , Países Baixos , Linhagem , Isoformas de Proteínas , Análise de Sequência de DNA , Transdução de Sinais , Peixe-Zebra
8.
J Am Soc Nephrol ; 28(11): 3291-3299, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28710092

RESUMO

Liddle syndrome is an autosomal dominant form of hypokalemic hypertension due to mutations in the ß- or γ-subunit of the epithelial sodium channel (ENaC). Here, we describe a family with Liddle syndrome due to a mutation in αENaC. The proband was referred because of resistant hypokalemic hypertension, suppressed renin and aldosterone, and no mutations in the genes encoding ß- or γENaC. Exome sequencing revealed a heterozygous, nonconservative T>C single-nucleotide mutation in αENaC that substituted Cys479 with Arg (C479R). C479 is a highly conserved residue in the extracellular domain of ENaC and likely involved in a disulfide bridge with the partner cysteine C394. In oocytes, the C479R and C394S mutations resulted in similar twofold increases in amiloride-sensitive ENaC current. Quantification of mature cleaved αENaC in membrane fractions showed that the number of channels did not increase with these mutations. Trypsin, which increases open probability of the channel by proteolytic cleavage, resulted in significantly higher currents in the wild type than in C479R or C394S mutants. In summary, a mutation in the extracellular domain of αENaC causes Liddle syndrome by increasing intrinsic channel activity. This mechanism differs from that of the ß- and γ-mutations, which result in an increase in channel density at the cell surface. This mutation may explain other cases of patients with resistant hypertension and also provides novel insight into ENaC activation, which is relevant for kidney sodium reabsorption and salt-sensitive hypertension.


Assuntos
Canais Epiteliais de Sódio/genética , Síndrome de Liddle/genética , Mutação de Sentido Incorreto , Humanos , Linhagem
9.
Eur J Med Genet ; 60(9): 445-450, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28602932

RESUMO

Using SNP array and FISH analysis, a patient with moderate intellectual disability and obesity was found to harbour an atypical 1.6 Mb inverted duplication on 8p23.1, directly flanked by a distally located interstitial deletion of 2.3 Mb and a terminal segmental uniparental disomy. The duplicated and deleted regions lie exactly between the two segmental duplication regions. These segmental duplications on chromosome 8p23.1 are known to be involved in chromosomal rearrangements because of mutual homology and homology to other genomic regions. Genomic instability mediated by these segmental duplications is generally caused by non-allelic homologous recombination, resulting in deletions, reciprocal duplications, inversions and translocations. Additional analysis of the parental origin of the fragments of this atypical inverted duplication/interstitial deletion shows paternal contribution in the maternal derivate chromosome 8. Combined with the finding that the normal chromosome 8 carries an inversion in 8p23.1 we hypothesize that a double strand break in 8p23.1 of the maternal chromosome was postzygotically repaired with the paternal inverted copy resulting in a duplication, deletion and segmental uniparental disomy, with no particular mediation of the 8p23.1 segmental duplication regions in recombination.


Assuntos
Transtornos Cromossômicos/genética , Deficiência Intelectual/genética , Obesidade/genética , Criança , Deleção Cromossômica , Transtornos Cromossômicos/diagnóstico , Duplicação Cromossômica , Cromossomos Humanos Par 8/genética , Humanos , Deficiência Intelectual/diagnóstico , Masculino , Obesidade/diagnóstico , Síndrome , Telômero/genética
10.
Proc Natl Acad Sci U S A ; 114(13): E2739-E2747, 2017 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-28292896

RESUMO

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a congenital visceral myopathy characterized by severe dilation of the urinary bladder and defective intestinal motility. The genetic basis of MMIHS has been ascribed to spontaneous and autosomal dominant mutations in actin gamma 2 (ACTG2), a smooth muscle contractile gene. However, evidence suggesting a recessive origin of the disease also exists. Using combined homozygosity mapping and whole exome sequencing, a genetically isolated family was found to carry a premature termination codon in Leiomodin1 (LMOD1), a gene preferentially expressed in vascular and visceral smooth muscle cells. Parents heterozygous for the mutation exhibited no abnormalities, but a child homozygous for the premature termination codon displayed symptoms consistent with MMIHS. We used CRISPR-Cas9 (CRISPR-associated protein) genome editing of Lmod1 to generate a similar premature termination codon. Mice homozygous for the mutation showed loss of LMOD1 protein and pathology consistent with MMIHS, including late gestation expansion of the bladder, hydronephrosis, and rapid demise after parturition. Loss of LMOD1 resulted in a reduction of filamentous actin, elongated cytoskeletal dense bodies, and impaired intestinal smooth muscle contractility. These results define LMOD1 as a disease gene for MMIHS and suggest its role in establishing normal smooth muscle cytoskeletal-contractile coupling.


Assuntos
Anormalidades Múltiplas/genética , Autoantígenos/fisiologia , Colo/anormalidades , Proteínas do Citoesqueleto/fisiologia , Pseudo-Obstrução Intestinal/genética , Proteínas Musculares/fisiologia , Bexiga Urinária/anormalidades , Animais , Autoantígenos/genética , Autoantígenos/metabolismo , Códon sem Sentido , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Feminino , Humanos , Recém-Nascido , Camundongos , Contração Muscular/genética , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Músculo Liso/fisiologia
11.
PLoS Genet ; 13(3): e1006683, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28346496

RESUMO

Schinzel-Giedion syndrome (SGS) is a rare developmental disorder characterized by multiple malformations, severe neurological alterations and increased risk of malignancy. SGS is caused by de novo germline mutations clustering to a 12bp hotspot in exon 4 of SETBP1. Mutations in this hotspot disrupt a degron, a signal for the regulation of protein degradation, and lead to the accumulation of SETBP1 protein. Overlapping SETBP1 hotspot mutations have been observed recurrently as somatic events in leukemia. We collected clinical information of 47 SGS patients (including 26 novel cases) with germline SETBP1 mutations and of four individuals with a milder phenotype caused by de novo germline mutations adjacent to the SETBP1 hotspot. Different mutations within and around the SETBP1 hotspot have varying effects on SETBP1 stability and protein levels in vitro and in in silico modeling. Substitutions in SETBP1 residue I871 result in a weak increase in protein levels and mutations affecting this residue are significantly more frequent in SGS than in leukemia. On the other hand, substitutions in residue D868 lead to the largest increase in protein levels. Individuals with germline mutations affecting D868 have enhanced cell proliferation in vitro and higher incidence of cancer compared to patients with other germline SETBP1 mutations. Our findings substantiate that, despite their overlap, somatic SETBP1 mutations driving malignancy are more disruptive to the degron than germline SETBP1 mutations causing SGS. Additionally, this suggests that the functional threshold for the development of cancer driven by the disruption of the SETBP1 degron is higher than for the alteration in prenatal development in SGS. Drawing on previous studies of somatic SETBP1 mutations in leukemia, our results reveal a genotype-phenotype correlation in germline SETBP1 mutations spanning a molecular, cellular and clinical phenotype.


Assuntos
Anormalidades Múltiplas/genética , Proteínas de Transporte/genética , Anormalidades Craniofaciais/genética , Predisposição Genética para Doença/genética , Deformidades Congênitas da Mão/genética , Neoplasias Hematológicas/genética , Deficiência Intelectual/genética , Mutação , Unhas Malformadas/genética , Proteínas Nucleares/genética , Anormalidades Múltiplas/metabolismo , Anormalidades Múltiplas/patologia , Western Blotting , Proteínas de Transporte/metabolismo , Linhagem Celular , Proliferação de Células/genética , Transformação Celular Neoplásica/genética , Criança , Pré-Escolar , Anormalidades Craniofaciais/metabolismo , Anormalidades Craniofaciais/patologia , Feminino , Perfilação da Expressão Gênica , Estudos de Associação Genética , Mutação em Linhagem Germinativa , Células HEK293 , Deformidades Congênitas da Mão/metabolismo , Deformidades Congênitas da Mão/patologia , Neoplasias Hematológicas/metabolismo , Neoplasias Hematológicas/patologia , Humanos , Lactente , Recém-Nascido , Deficiência Intelectual/metabolismo , Deficiência Intelectual/patologia , Masculino , Unhas Malformadas/metabolismo , Unhas Malformadas/patologia , Proteínas Nucleares/metabolismo , Fenótipo
12.
Genome Biol ; 18(1): 48, 2017 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-28274275

RESUMO

BACKGROUND: Hirschsprung disease (HSCR), which is congenital obstruction of the bowel, results from a failure of enteric nervous system (ENS) progenitors to migrate, proliferate, differentiate, or survive within the distal intestine. Previous studies that have searched for genes underlying HSCR have focused on ENS-related pathways and genes not fitting the current knowledge have thus often been ignored. We identify and validate novel HSCR genes using whole exome sequencing (WES), burden tests, in silico prediction, unbiased in vivo analyses of the mutated genes in zebrafish, and expression analyses in zebrafish, mouse, and human. RESULTS: We performed de novo mutation (DNM) screening on 24 HSCR trios. We identify 28 DNMs in 21 different genes. Eight of the DNMs we identified occur in RET, the main HSCR gene, and the remaining 20 DNMs reside in genes not reported in the ENS. Knockdown of all 12 genes with missense or loss-of-function DNMs showed that the orthologs of four genes (DENND3, NCLN, NUP98, and TBATA) are indispensable for ENS development in zebrafish, and these results were confirmed by CRISPR knockout. These genes are also expressed in human and mouse gut and/or ENS progenitors. Importantly, the encoded proteins are linked to neuronal processes shared by the central nervous system and the ENS. CONCLUSIONS: Our data open new fields of investigation into HSCR pathology and provide novel insights into the development of the ENS. Moreover, the study demonstrates that functional analyses of genes carrying DNMs are warranted to delineate the full genetic architecture of rare complex diseases.


Assuntos
Exoma , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Sequenciamento de Nucleotídeos em Larga Escala , Doença de Hirschsprung/genética , Alelos , Animais , Estudos de Casos e Controles , Biologia Computacional/métodos , Análise Mutacional de DNA , Modelos Animais de Doenças , Técnicas de Inativação de Genes , Genótipo , Humanos , Mutação , Fenótipo , Peixe-Zebra
13.
Hum Reprod ; 32(2): 299-306, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-28057877

RESUMO

STUDY QUESTION: Are anorectal malformations (ARMs) associated with previous miscarriages or single nucleotide polymorphisms (SNPs) in the Bone Morphogenetic Protein 4 (BMP4) and GLI family zinc finger 2 (GLI2) genes? SUMMARY ANSWER: The SNP rs3738880 in GLI2 and miscarriages were associated with ARM, especially in patients with multiple congenital anomalies (MCA). WHAT IS KNOWN ALREADY: ARM are one of the most common birth defects of the gastrointestinal tract. The etiology is likely to be multifactorial, involving both environmental and genetic factors. SNPs in BMP4 and GLI2 genes were associated with ARM in non-Caucasian populations. During a patient information day, several mothers of ARM patients reported their concerns about previous miscarriages. STUDY DESIGN, SIZE, DURATION: A case-control study was performed among 427 ARM patients and 663 population-based controls. PARTICIPANTS/MATERIALS, SETTING, METHODS: We examined the associations of ARM with SNPs in GLI2 and BMP4 using DNA samples of the children and associations with previous miscarriages using parental questionnaires. In addition, gene-gene and gene-environment interaction analyses were performed. MAIN RESULTS AND THE ROLE OF CHANCE: The SNP rs3738880 in GLI2 was associated with ARM, especially in patients with MCA (homozygous GG-genotype: odds ratio (OR): 2.1; 95% CI: 1.2, 3.7). We identified previous miscarriages as a new risk factor for ARM, especially when occurring in the pregnancy directly preceding the index pregnancy and in patients with MCA (OR: 2.1; 95% CI: 1.3, 3.5). No association with rs17563 in BMP4, nor gene-gene or gene-environment interactions were found. LIMITATIONS, REASONS FOR CAUTION: The possibility of recall errors for previous miscarriage, but we expect these errors to be limited, as a miscarriage is a major life event. In addition, potential misclassification regarding miscarriages and stillbirth, but sensitivity analyses showed that this did not influence our results. WIDER IMPLICATIONS OF THE FINDINGS: This study showed associations of ARM with rs3738880 in GLI2 and with previous miscarriages. Both associations were stronger in patients with MCA, showing the importance of stratifying the analyses by patients with isolated ARM or MCA. STUDY FUNDING/COMPETING INTERESTS: This study was funded by the Radboudumc. The authors have no conflict of interest to disclose.


Assuntos
Aborto Habitual/genética , Malformações Anorretais/etiologia , Proteínas Nucleares/genética , Proteína Gli2 com Dedos de Zinco/genética , Adulto , Malformações Anorretais/genética , Proteína Morfogenética Óssea 4/genética , Estudos de Casos e Controles , Feminino , Genótipo , Humanos , Recém-Nascido , Masculino , Polimorfismo de Nucleotídeo Único , Gravidez , Inquéritos e Questionários
14.
Eur J Hum Genet ; 24(12): 1715-1723, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27436264

RESUMO

Oesophageal atresia (OA) with or without tracheoesophageal fistula (TOF) are rare anatomical congenital malformations whose cause is unknown in over 90% of patients. A genetic background is suggested, and among the reported genetic defects are copy number variations (CNVs). We hypothesized that CNVs contribute to OA/TOF development. Quantifying their prevalence could aid in genetic diagnosis and clinical care strategies. Therefore, we profiled 375 patients in a combined Dutch, American and German cohort via genomic microarray and compared the CNV profiles with their unaffected parents and published control cohorts. We identified 167 rare CNVs containing genes (frequency<0.0005 in our in-house cohort). Eight rare CNVs - in six patients - were de novo, including one CNV previously associated with oesophageal disease. (hg19 chr7:g.(143820444_143839360)_(159119486_159138663)del) 1.55% of isolated OA/TOF patients and 1.62% of patients with additional congenital anomalies had de novo CNVs. Furthermore, three (15q13.3, 16p13.3 and 22q11.2) susceptibility loci were identified based on their overlap with known OA/TOF-associated CNV syndromes and overlap with loci in published CNV association case-control studies in developmental delay. Our study suggests that CNVs contribute to OA/TOF development. In addition to the identified likely deleterious de novo CNVs, we detected 167 rare CNVs. Although not directly disease-causing, these CNVs might be of interest, as they can act as a modifier in a multiple hit model, or as the second hit in a recessive condition.


Assuntos
Variações do Número de Cópias de DNA , Atresia Esofágica/genética , Fístula Traqueoesofágica/genética , Adulto , Criança , Loci Gênicos , Estudo de Associação Genômica Ampla , Humanos
15.
Dev Biol ; 417(2): 198-208, 2016 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-27426273

RESUMO

Abnormal development or disturbed functioning of the enteric nervous system (ENS), the intrinsic innervation of the gastrointestinal tract, is associated with the development of neuropathic gastrointestinal motility disorders. Here, we review the underlying molecular basis of these disorders and hypothesize that many of them have a common defective biological mechanism. Genetic burden and environmental components affecting this common mechanism are ultimately responsible for disease severity and symptom heterogeneity. We believe that they act together as the fulcrum in a seesaw balanced with harmful and protective factors, and are responsible for a continuum of symptoms ranging from neuronal hyperplasia to absence of neurons.


Assuntos
Sistema Nervoso Entérico/patologia , Motilidade Gastrointestinal/fisiologia , Trato Gastrointestinal/inervação , Trato Gastrointestinal/patologia , Interação Gene-Ambiente , Sistema Nervoso Entérico/crescimento & desenvolvimento , Motilidade Gastrointestinal/genética , Doença de Hirschsprung/genética , Humanos , Miócitos de Músculo Liso/fisiologia
17.
Am J Hum Genet ; 98(2): 373-81, 2016 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-26833328

RESUMO

Mutations in more than a hundred genes have been reported to cause X-linked recessive intellectual disability (ID) mainly in males. In contrast, the number of identified X-linked genes in which de novo mutations specifically cause ID in females is limited. Here, we report 17 females with de novo loss-of-function mutations in USP9X, encoding a highly conserved deubiquitinating enzyme. The females in our study have a specific phenotype that includes ID/developmental delay (DD), characteristic facial features, short stature, and distinct congenital malformations comprising choanal atresia, anal abnormalities, post-axial polydactyly, heart defects, hypomastia, cleft palate/bifid uvula, progressive scoliosis, and structural brain abnormalities. Four females from our cohort were identified by targeted genetic testing because their phenotype was suggestive for USP9X mutations. In several females, pigment changes along Blaschko lines and body asymmetry were observed, which is probably related to differential (escape from) X-inactivation between tissues. Expression studies on both mRNA and protein level in affected-female-derived fibroblasts showed significant reduction of USP9X level, confirming the loss-of-function effect of the identified mutations. Given that some features of affected females are also reported in known ciliopathy syndromes, we examined the role of USP9X in the primary cilium and found that endogenous USP9X localizes along the length of the ciliary axoneme, indicating that its loss of function could indeed disrupt cilium-regulated processes. Absence of dysregulated ciliary parameters in affected female-derived fibroblasts, however, points toward spatiotemporal specificity of ciliary USP9X (dys-)function.


Assuntos
Deficiências do Desenvolvimento/genética , Deficiência Intelectual/genética , Mutação , Ubiquitina Tiolesterase/genética , Adolescente , Sequência de Bases , Criança , Pré-Escolar , Atresia das Cóanas/diagnóstico , Atresia das Cóanas/genética , Deficiências do Desenvolvimento/diagnóstico , Feminino , Genes Ligados ao Cromossomo X , Testes Genéticos , Humanos , Deficiência Intelectual/diagnóstico , Dados de Sequência Molecular , Fenótipo , Ubiquitina Tiolesterase/metabolismo , Inativação do Cromossomo X , Adulto Jovem
18.
Eur J Hum Genet ; 24(5): 652-9, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26306646

RESUMO

The Koolen-de Vries syndrome (KdVS; OMIM #610443), also known as the 17q21.31 microdeletion syndrome, is a clinically heterogeneous disorder characterised by (neonatal) hypotonia, developmental delay, moderate intellectual disability, and characteristic facial dysmorphism. Expressive language development is particularly impaired compared with receptive language or motor skills. Other frequently reported features include social and friendly behaviour, epilepsy, musculoskeletal anomalies, congenital heart defects, urogenital malformations, and ectodermal anomalies. The syndrome is caused by a truncating variant in the KAT8 regulatory NSL complex unit 1 (KANSL1) gene or by a 17q21.31 microdeletion encompassing KANSL1. Herein we describe a novel cohort of 45 individuals with KdVS of whom 33 have a 17q21.31 microdeletion and 12 a single-nucleotide variant (SNV) in KANSL1 (19 males, 26 females; age range 7 months to 50 years). We provide guidance about the potential pitfalls in the laboratory testing and emphasise the challenges of KANSL1 variant calling and DNA copy number analysis in the complex 17q21.31 region. Moreover, we present detailed phenotypic information, including neuropsychological features, that contribute to the broad phenotypic spectrum of the syndrome. Comparison of the phenotype of both the microdeletion and SNV patients does not show differences of clinical importance, stressing that haploinsufficiency of KANSL1 is sufficient to cause the full KdVS phenotype.


Assuntos
Anormalidades Múltiplas/diagnóstico , Deficiência Intelectual/diagnóstico , Proteínas Nucleares/genética , Fenótipo , Polimorfismo de Nucleotídeo Único , Anormalidades Múltiplas/genética , Adolescente , Adulto , Criança , Deleção Cromossômica , Cromossomos Humanos Par 17/genética , Feminino , Humanos , Deficiência Intelectual/genética , Masculino , Pessoa de Meia-Idade
19.
Hum Mol Genet ; 25(3): 571-83, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26647307

RESUMO

Megacystis Microcolon Intestinal Hypoperistalsis Syndrome (MMIHS) is a rare congenital disorder, in which heterozygous missense variants in the Enteric Smooth Muscle actin γ-2 (ACTG2) gene have been recently identified. To investigate the mechanism by which ACTG2 variants lead to MMIHS, we screened a cohort of eleven MMIHS patients, eight sporadic and three familial cases, and performed immunohistochemistry, molecular modeling and molecular dynamics (MD) simulations, and in vitro assays. In all sporadic cases, a heterozygous missense variant in ACTG2 was identified. ACTG2 expression was detected in all intestinal layers where smooth muscle cells are present in different stages of human development. No histopathological abnormalities were found in the patients. Using molecular modeling and MD simulations, we predicted that ACTG2 variants lead to significant changes to the protein function. This was confirmed by in vitro studies, which showed that the identified variants not only impair ACTG2 polymerization, but also contribute to reduced cell contractility. Taken together, our results confirm the involvement of ACTG2 in sporadic MMIHS, and bring new insights to MMIHS pathogenesis.


Assuntos
Anormalidades Múltiplas/genética , Actinas/genética , Colo/anormalidades , Mucosa Intestinal/metabolismo , Pseudo-Obstrução Intestinal/genética , Contração Muscular/genética , Músculo Liso/metabolismo , Mutação de Sentido Incorreto , Bexiga Urinária/anormalidades , Anormalidades Múltiplas/metabolismo , Anormalidades Múltiplas/patologia , Actinas/química , Actinas/metabolismo , Colo/metabolismo , Colo/patologia , Evolução Fatal , Feminino , Expressão Gênica , Heterozigoto , Humanos , Recém-Nascido , Pseudo-Obstrução Intestinal/metabolismo , Pseudo-Obstrução Intestinal/patologia , Intestinos/patologia , Masculino , Simulação de Dinâmica Molecular , Músculo Liso/patologia , Linhagem , Multimerização Proteica , Bexiga Urinária/metabolismo , Bexiga Urinária/patologia , Adulto Jovem
20.
Int J Pediatr Otorhinolaryngol ; 79(7): 1164-70, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25998214

RESUMO

We report on a family with a not earlier described multiple congenital malformation. Several male family members suffer from laryngeal obstruction caused by bilateral vocal cord paralysis, outer and middle ear deformity with conductive and sensorineural hearing loss, facial dysmorphisms, and underdeveloped shoulder musculature. The affected female members only have middle ear deformity and hearing loss. The pedigree is suggestive of an X-linked recessive inheritance pattern. SNP-array revealed a deletion and duplication on Xq28 in the affected family members. A possible aetiology is a neurocristopathy with most symptoms expressed in structures derived from branchial arches.


Assuntos
Anormalidades Craniofaciais/genética , Orelha Externa/anormalidades , Orelha Média/anormalidades , Perda Auditiva Condutiva/genética , Músculo Esquelético/anormalidades , Paralisia das Pregas Vocais/genética , Anormalidades Múltiplas/genética , Deleção Cromossômica , Duplicação Cromossômica , Cromossomos Humanos X/genética , Feminino , Perda Auditiva Neurossensorial/genética , Humanos , Masculino , Países Baixos , Linhagem , Síndrome
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