Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Am J Hum Genet ; 105(2): 403-412, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31303265

RESUMO

POU3F3, also referred to as Brain-1, is a well-known transcription factor involved in the development of the central nervous system, but it has not previously been associated with a neurodevelopmental disorder. Here, we report the identification of 19 individuals with heterozygous POU3F3 disruptions, most of which are de novo variants. All individuals had developmental delays and/or intellectual disability and impairments in speech and language skills. Thirteen individuals had characteristic low-set, prominent, and/or cupped ears. Brain abnormalities were observed in seven of eleven MRI reports. POU3F3 is an intronless gene, insensitive to nonsense-mediated decay, and 13 individuals carried protein-truncating variants. All truncating variants that we tested in cellular models led to aberrant subcellular localization of the encoded protein. Luciferase assays demonstrated negative effects of these alleles on transcriptional activation of a reporter with a FOXP2-derived binding motif. In addition to the loss-of-function variants, five individuals had missense variants that clustered at specific positions within the functional domains, and one small in-frame deletion was identified. Two missense variants showed reduced transactivation capacity in our assays, whereas one variant displayed gain-of-function effects, suggesting a distinct pathophysiological mechanism. In bioluminescence resonance energy transfer (BRET) interaction assays, all the truncated POU3F3 versions that we tested had significantly impaired dimerization capacities, whereas all missense variants showed unaffected dimerization with wild-type POU3F3. Taken together, our identification and functional cell-based analyses of pathogenic variants in POU3F3, coupled with a clinical characterization, implicate disruptions of this gene in a characteristic neurodevelopmental disorder.

2.
Am J Hum Genet ; 104(6): 1210-1222, 2019 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-31079897

RESUMO

We delineate a KMT2E-related neurodevelopmental disorder on the basis of 38 individuals in 36 families. This study includes 31 distinct heterozygous variants in KMT2E (28 ascertained from Matchmaker Exchange and three previously reported), and four individuals with chromosome 7q22.2-22.23 microdeletions encompassing KMT2E (one previously reported). Almost all variants occurred de novo, and most were truncating. Most affected individuals with protein-truncating variants presented with mild intellectual disability. One-quarter of individuals met criteria for autism. Additional common features include macrocephaly, hypotonia, functional gastrointestinal abnormalities, and a subtle facial gestalt. Epilepsy was present in about one-fifth of individuals with truncating variants and was responsive to treatment with anti-epileptic medications in almost all. More than 70% of the individuals were male, and expressivity was variable by sex; epilepsy was more common in females and autism more common in males. The four individuals with microdeletions encompassing KMT2E generally presented similarly to those with truncating variants, but the degree of developmental delay was greater. The group of four individuals with missense variants in KMT2E presented with the most severe developmental delays. Epilepsy was present in all individuals with missense variants, often manifesting as treatment-resistant infantile epileptic encephalopathy. Microcephaly was also common in this group. Haploinsufficiency versus gain-of-function or dominant-negative effects specific to these missense variants in KMT2E might explain this divergence in phenotype, but requires independent validation. Disruptive variants in KMT2E are an under-recognized cause of neurodevelopmental abnormalities.

3.
Genet Med ; 21(9): 2059-2069, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30923367

RESUMO

PURPOSE: To investigate the effect of different DEAF1 variants on the phenotype of patients with autosomal dominant and recessive inheritance patterns and on DEAF1 activity in vitro. METHODS: We assembled a cohort of 23 patients with de novo and biallelic DEAF1 variants, described the genotype-phenotype correlation, and investigated the differential effect of de novo and recessive variants on transcription assays using DEAF1 and Eif4g3 promoter luciferase constructs. RESULTS: The proportion of the most prevalent phenotypic features, including intellectual disability, speech delay, motor delay, autism, sleep disturbances, and a high pain threshold, were not significantly different in patients with biallelic and pathogenic de novo DEAF1 variants. However, microcephaly was exclusively observed in patients with recessive variants (p < 0.0001). CONCLUSION: We propose that different variants in the DEAF1 gene result in a phenotypic spectrum centered around neurodevelopmental delay. While a pathogenic de novo dominant variant would also incapacitate the product of the wild-type allele and result in a dominant-negative effect, a combination of two recessive variants would result in a partial loss of function. Because the clinical picture can be nonspecific, detailed phenotype information, segregation, and functional analysis are fundamental to determine the pathogenicity of novel variants and to improve the care of these patients.

4.
Eur J Hum Genet ; 2018 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-30291340

RESUMO

Deletions on chromosome 15q14 are a known chromosomal cause of cleft palate, typically co-occurring with intellectual disability, facial dysmorphism, and congenital heart defects. The identification of patients with loss-of-function variants in MEIS2, a gene within this deletion, suggests that these features are attributed to haploinsufficiency of MEIS2. To further delineate the phenotypic spectrum of the MEIS2-related syndrome, we collected 23 previously unreported patients with either a de novo sequence variant in MEIS2 (9 patients), or a 15q14 microdeletion affecting MEIS2 (14 patients). All but one de novo MEIS2 variant were identified by whole-exome sequencing. One variant was found by targeted sequencing of MEIS2 in a girl with a clinical suspicion of this syndrome. In addition to the triad of palatal defects, heart defects, and developmental delay, heterozygous loss of MEIS2 results in recurrent facial features, including thin and arched eyebrows, short alae nasi, and thin vermillion. Genotype-phenotype comparison between patients with 15q14 deletions and patients with sequence variants or intragenic deletions within MEIS2, showed a higher prevalence of moderate-to-severe intellectual disability in the former group, advocating for an independent locus for psychomotor development neighboring MEIS2.

5.
Invest Ophthalmol Vis Sci ; 59(11): 4384-4391, 2018 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-30193310

RESUMO

Purpose: To describe the phenotypic spectrum of retinal disease caused by the c.2991+1655A>G mutation in CEP290 and to compare disease severity between homozygous and compound heterozygous patients. Methods: Medical records were reviewed for best-corrected visual acuity (BCVA), age of onset, fundoscopy descriptions. Foveal outer nuclear layer (ONL) and ellipsoid zone (EZ) presence was assessed using spectral-domain optical coherence tomography (SD-OCT). Differences between compound heterozygous and homozygous patients were analyzed based on visual performance and visual development. Results: A total of 66 patients were included. The majority of patients had either light perception or no light perception. In the remaining group of 14 patients, median BCVA was 20/195 Snellen (0.99 LogMAR; range 0.12-1.90) for the right eye, and 20/148 Snellen (0.87 LogMAR; range 0.22-1.90) for the left. Homozygous patients tended to be more likely to develop light perception compared to more severely affected compound heterozygous patients (P = 0.080) and are more likely to improve from no light perception to light perception (P = 0.022) before the age of 6 years. OCT data were available in 12 patients, 11 of whom had retained foveal ONL and EZ integrity up to 48 years (median 23 years) of age. Conclusions: Homozygous patients seem less severely affected compared to their compound-heterozygous peers. Improvement of visual function may occur in the early years of life, suggesting a time window for therapeutic intervention up to the approximate age of 17 years. This period may be extended by an intact foveal ONL and EZ on OCT.

6.
Hum Mol Genet ; 2018 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-30239721

RESUMO

Loss-of-function mutations in glutaminase (GLS), the enzyme converting glutamine into glutamate, and the counteracting enzyme glutamine synthetase (GS) cause disturbed glutamate homeostasis and severe neonatal encephalopathy. We report a de novo Ser482Cys gain-of-function variant in GLS encoding glutaminase associated with profound developmental delay and infantile cataract. Functional analysis demonstrated that this variant causes hyperactivity and compensatory downregulation of GLS expression combined with upregulation of the counteracting enzyme GS, supporting pathogenicity. Ser482Cys-GLS likely improves the electrostatic environment of the GLS catalytic site, thereby intrinsically inducing hyperactivity. Alignment of +/-12.000 GLS protein sequences from >1000 genera, revealed extreme conservation of Ser482, to the same degree as catalytic residues. Together with the hyperactivity, this indicates that Ser482 is evolutionarily preserved to achieve optimal -but submaximal- GLS activity. In line with GLS hyperactivity, increased glutamate and decreased glutamine concentrations were measured in urine and fibroblasts. In the brain (both grey and white matter), glutamate was also extremely high and glutamine almost undetectable, using ultra-high field magnetic resonance spectroscopic imaging. Considering the neurotoxicity of glutamate when present in excess, the strikingly high glutamate concentrations measured in the brain provide an explanation for the developmental delay. Cataract, a known consequence of oxidative stress, was evoked in zebrafish expressing the hypermorphic Ser482Cys-GLS and could be alleviated by inhibition of GLS. The capacity to detoxify reactive oxygen species was reduced upon Ser482Cys-GLS expression, providing an explanation for cataract formation. In conclusion, we describe an inborn error of glutamate metabolism caused by a GLS hyperactivity variant, illustrating the importance of balanced GLS activity.

7.
Am J Med Genet A ; 2018 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-30194818

RESUMO

De novo germline mutations in GNB1 have been associated with a neurodevelopmental phenotype. To date, 28 patients with variants classified as pathogenic have been reported. We add 18 patients with de novo mutations to this cohort, including a patient with mosaicism for a GNB1 mutation who presented with a milder phenotype. Consistent with previous reports, developmental delay in these patients was moderate to severe, and more than half of the patients were non-ambulatory and nonverbal. The most observed substitution affects the p.Ile80 residue encoded in exon 6, with 28% of patients carrying a variant at this residue. Dystonia and growth delay were observed more frequently in patients carrying variants in this residue, suggesting a potential genotype-phenotype correlation. In the new cohort of 18 patients, 50% of males had genitourinary anomalies and 61% of patients had gastrointestinal anomalies, suggesting a possible association of these findings with variants in GNB1. In addition, cutaneous mastocytosis, reported once before in a patient with a GNB1 variant, was observed in three additional patients, providing further evidence for an association to GNB1. We will review clinical and molecular data of these new cases and all previously reported cases to further define the phenotype and establish possible genotype-phenotype correlations.

8.
Pediatr Nephrol ; 33(10): 1701-1712, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29974258

RESUMO

BACKGROUND: Nephronophthisis is an autosomal recessive ciliopathy and important cause of end-stage renal disease (ESRD) in children and young adults. Diagnostic delay is frequent. This study investigates clinical characteristics, initial symptoms, and genetic defects in a cohort with nephronophthisis-related ciliopathy, to improve early detection and genetic counseling. METHODS: Forty patients from 36 families with nephronophthisis-related ciliopathy were recruited at university medical centers and online. Comprehensive clinical and genotypic data were recorded. Patients without molecular diagnosis were offered genetic analysis. RESULTS: Of 40 patients, 45% had isolated nephronophthisis, 48% syndromic diagnosis, and 7% nephronophthisis with extrarenal features not constituting a recognizable syndrome. Patients developed ESRD at median 13 years (range 5-47). Median age of symptom onset was 9 years in both isolated and syndromic forms (range 5-26 vs. 5-33). Common presenting symptoms were fatigue (42%), polydipsia/polyuria (33%), and hypertension (21%). Renal ultrasound showed small-to-normal-sized kidneys, increased echogenicity (65%), cysts (43%), and abnormal corticomedullary differentiation (32%). Renal biopsies in eight patients showed nonspecific signs of chronic kidney disease (CKD). Twenty-three patients (58%) had genetic diagnosis upon inclusion. Thirteen of those without a genetic diagnosis gave consent for genetic testing, and a cause was identified in five (38%). CONCLUSIONS: Nephronophthisis is genetically and phenotypically heterogeneous and should be considered in children and young adults presenting with persistent fatigue and polyuria, and in all patients with unexplained CKD. As symptom onset can occur into adulthood, presymptomatic monitoring of kidney function in syndromic ciliopathy patients should continue until at least age 30.

9.
Brain ; 140(11): 2879-2894, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-29053855

RESUMO

Genetic epilepsies are caused by mutations in a range of different genes, many of them encoding ion channels, receptors or transporters. While the number of detected variants and genes increased dramatically in the recent years, pleiotropic effects have also been recognized, revealing that clinical syndromes with various degrees of severity arise from a single gene, a single mutation, or from different mutations showing similar functional defects. Accordingly, several genes coding for GABAA receptor subunits have been linked to a spectrum of benign to severe epileptic disorders and it was shown that a loss of function presents the major correlated pathomechanism. Here, we identified six variants in GABRA3 encoding the α3-subunit of the GABAA receptor. This gene is located on chromosome Xq28 and has not been previously associated with human disease. Five missense variants and one microduplication were detected in four families and two sporadic cases presenting with a range of epileptic seizure types, a varying degree of intellectual disability and developmental delay, sometimes with dysmorphic features or nystagmus. The variants co-segregated mostly but not completely with the phenotype in the families, indicating in some cases incomplete penetrance, involvement of other genes, or presence of phenocopies. Overall, males were more severely affected and there were three asymptomatic female mutation carriers compared to only one male without a clinical phenotype. X-chromosome inactivation studies could not explain the phenotypic variability in females. Three detected missense variants are localized in the extracellular GABA-binding NH2-terminus, one in the M2-M3 linker and one in the M4 transmembrane segment of the α3-subunit. Functional studies in Xenopus laevis oocytes revealed a variable but significant reduction of GABA-evoked anion currents for all mutants compared to wild-type receptors. The degree of current reduction correlated partially with the phenotype. The microduplication disrupted GABRA3 expression in fibroblasts of the affected patient. In summary, our results reveal that rare loss-of-function variants in GABRA3 increase the risk for a varying combination of epilepsy, intellectual disability/developmental delay and dysmorphic features, presenting in some pedigrees with an X-linked inheritance pattern.


Assuntos
Encefalopatias/genética , Fissura Palatina/genética , Deficiências do Desenvolvimento/genética , Epilepsia/genética , Facies , Deficiência Intelectual/genética , Nistagmo Patológico/genética , Receptores de GABA-A/genética , Adolescente , Adulto , Animais , Criança , Pré-Escolar , Feminino , Variação Genética , Humanos , Masculino , Microcefalia/genética , Mutagênese Sítio-Dirigida , Oócitos/metabolismo , Técnicas de Patch-Clamp , Linhagem , Receptores de GABA-A/metabolismo , Síndrome , Xenopus laevis , Adulto Jovem , Ácido gama-Aminobutírico/metabolismo
10.
Eur J Hum Genet ; 25(5): 591-599, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28224992

RESUMO

Inherited eye disorders have a large clinical and genetic heterogeneity, which makes genetic diagnosis cumbersome. An exome-sequencing approach was developed in which data analysis was divided into two steps: the vision gene panel and exome analysis. In the vision gene panel analysis, variants in genes known to cause inherited eye disorders were assessed for pathogenicity. If no causative variants were detected and when the patient consented, the entire exome data was analyzed. A total of 266 Dutch patients with different types of inherited eye disorders, including inherited retinal dystrophies, cataract, developmental eye disorders and optic atrophy, were investigated. In the vision gene panel analysis (likely), causative variants were detected in 49% and in the exome analysis in an additional 2% of the patients. The highest detection rate of (likely) causative variants was in patients with inherited retinal dystrophies, for instance a yield of 63% in patients with retinitis pigmentosa. In patients with developmental eye defects, cataract and optic atrophy, the detection rate was 50, 33 and 17%, respectively. An exome-sequencing approach enables a genetic diagnosis in patients with different types of inherited eye disorders using one test. The exome approach has the same detection rate as targeted panel sequencing tests, but offers a number of advantages. For instance, the vision gene panel can be frequently and easily updated with additional (novel) eye disorder genes. Determination of the genetic diagnosis improved the clinical diagnosis, regarding the assessment of the inheritance pattern as well as future disease perspective.


Assuntos
Exoma , Oftalmopatias Hereditárias/genética , Padrões de Herança , Transtornos da Visão/genética , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Oftalmopatias Hereditárias/patologia , Humanos , Países Baixos , Transtornos da Visão/patologia
11.
Genet Med ; 18(9): 949-56, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26845106

RESUMO

PURPOSE: This study investigated whole-exome sequencing (WES) yield in a subset of intellectually disabled patients referred to our clinical diagnostic center and calculated the total costs of these patients' diagnostic trajectory in order to evaluate early WES implementation. METHODS: We compared 17 patients' trio-WES yield with the retrospective costs of diagnostic procedures by comprehensively examining patient records and collecting resource use information for each patient, beginning with patient admittance and concluding with WES initiation. We calculated cost savings using scenario analyses to evaluate the costs replaced by WES when used as a first diagnostic tool. RESULTS: WES resulted in diagnostically useful outcomes in 29.4% of patients. The entire traditional diagnostic trajectory average cost was $16,409 per patient, substantially higher than the $3,972 trio-WES cost. WES resulted in average cost savings of $3,547 for genetic and metabolic investigations in diagnosed patients and $1,727 for genetic investigations in undiagnosed patients. CONCLUSION: The increased causal variant detection yield by WES and the relatively high costs of the entire traditional diagnostic trajectory suggest that early implementation of WES is a relevant and cost-efficient option in patient diagnostics. This information is crucial for centers considering implementation of WES and serves as input for future value-based research into diagnostics.Genet Med 18 9, 949-956.


Assuntos
Testes Genéticos/economia , Sequenciamento de Nucleotídeos em Larga Escala , Deficiência Intelectual/diagnóstico , Sequenciamento Completo do Exoma/métodos , Custos e Análise de Custo , Exoma , Feminino , Humanos , Deficiência Intelectual/economia , Deficiência Intelectual/genética , Masculino , Análise de Sequência de DNA , Sequenciamento Completo do Exoma/economia
12.
Genet Med ; 18(9): 882-91, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26765342

RESUMO

PURPOSE: The Ehlers-Danlos syndrome (EDS), dermatosparaxis type, is a recessively inherited connective tissue disorder caused by deficient activity of ADAMTS-2, an enzyme that cleaves the aminoterminal propeptide domain of types I, II, and III procollagen. Only 10 EDS dermatosparaxis patients have been reported, all presenting a recognizable phenotype with characteristic facial gestalt, extreme skin fragility and laxity, excessive bruising, and sometimes major complications due to visceral and vascular fragility. METHODS: We report on five new EDS dermatosparaxis patients and provide a comprehensive overview of the current knowledge of the natural history of this condition. RESULTS: We identified three novel homozygous loss-of-function mutations (c.2927_2928delCT, p.(Pro976Argfs*42); c.669_670dupG, p.(Pro224Argfs*24); and c.2751-2A>T) and one compound heterozygous mutation (c.2T>C, p.? and c.884_887delTGAA, p.(Met295Thrfs26*)) in ADAMTS2 in five patients from four unrelated families. Three of these displayed a phenotype that was strikingly milder than that of previously reported patients. CONCLUSION: This study expands the clinical and molecular spectrum of the dermatosparaxis type of EDS to include a milder phenotypic variant and stresses the importance of good clinical criteria. To address this, we propose an updated set of criteria that accurately captures the multisystemic nature of the dermatosparaxis type of EDS.Genet Med 18 9, 882-891.


Assuntos
Proteínas ADAMTS/genética , Síndrome de Ehlers-Danlos/genética , Adolescente , Adulto , Criança , Pré-Escolar , Síndrome de Ehlers-Danlos/complicações , Síndrome de Ehlers-Danlos/patologia , Feminino , Humanos , Masculino , Mutação , Fenótipo
13.
J Med Genet ; 53(1): 62-72, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26490104

RESUMO

BACKGROUND: Joubert syndrome (JS) is a recessive ciliopathy characterised by a distinctive brain malformation 'the molar tooth sign'. Mutations in >27 genes cause JS, and mutations in 12 of these genes also cause Meckel-Gruber syndrome (MKS). The goals of this work are to describe the clinical features of MKS1-related JS and determine whether disease causing MKS1 mutations affect cellular phenotypes such as cilium number, length and protein content as potential mechanisms underlying JS. METHODS: We measured cilium number, length and protein content (ARL13B and INPP5E) by immunofluorescence in fibroblasts from individuals with MKS1-related JS and in a three-dimensional (3D) spheroid rescue assay to test the effects of disease-related MKS1 mutations. RESULTS: We report MKS1 mutations (eight of them previously unreported) in nine individuals with JS. A minority of the individuals with MKS1-related JS have MKS features. In contrast to the truncating mutations associated with MKS, all of the individuals with MKS1-related JS carry ≥ 1 non-truncating mutation. Fibroblasts from individuals with MKS1-related JS make normal or fewer cilia than control fibroblasts, their cilia are more variable in length than controls, and show decreased ciliary ARL13B and INPP5E. Additionally, MKS1 mutant alleles have similar effects in 3D spheroids. CONCLUSIONS: MKS1 functions in the transition zone at the base of the cilium to regulate ciliary INPP5E content, through an ARL13B-dependent mechanism. Mutations in INPP5E also cause JS, so our findings in patient fibroblasts support the notion that loss of INPP5E function, due to either mutation or mislocalisation, is a key mechanism underlying JS, downstream of MKS1 and ARL13B.


Assuntos
Anormalidades Múltiplas/genética , Anormalidades Múltiplas/metabolismo , Cerebelo/anormalidades , Cílios/genética , Cílios/metabolismo , Anormalidades do Olho/genética , Anormalidades do Olho/metabolismo , Doenças Renais Císticas/genética , Doenças Renais Císticas/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Proteínas/genética , Proteínas/metabolismo , Retina/anormalidades , Fatores de Ribosilação do ADP/metabolismo , Anormalidades Múltiplas/diagnóstico , Animais , Encéfalo/patologia , Células Cultivadas , Cerebelo/metabolismo , Cílios/patologia , Éxons , Anormalidades do Olho/diagnóstico , Fibroblastos/metabolismo , Fibroblastos/patologia , Regulação da Expressão Gênica , Humanos , Doenças Renais Císticas/diagnóstico , Imagem por Ressonância Magnética , Camundongos , Modelos Biológicos , Mutação , Ligação Proteica , Transporte Proteico , Retina/metabolismo , Tomografia Computadorizada por Raios X
14.
Eur J Hum Genet ; 24(2): 214-20, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25920555

RESUMO

Joubert syndrome (JBS) is a rare neurodevelopmental disorder belonging to the group of ciliary diseases. JBS is genetically heterogeneous, with >20 causative genes identified to date. A molecular diagnosis of JBS is essential for prediction of disease progression and genetic counseling. We developed a targeted next-generation sequencing (NGS) approach for parallel sequencing of 22 known JBS genes plus 599 additional ciliary genes. This method was used to genotype a cohort of 51 well-phenotyped Northern European JBS cases (in some of the cases, Sanger sequencing of individual JBS genes had been performed previously). Altogether, 21 of the 51 cases (41%) harbored biallelic pathogenic mutations in known JBS genes, including 14 mutations not previously described. Mutations in C5orf42 (12%), TMEM67 (10%), and AHI1 (8%) were the most prevalent. C5orf42 mutations result in a purely neurological Joubert phenotype, in one case associated with postaxial polydactyly. Our study represents a population-based cohort of JBS patients not enriched for consanguinity, providing insight into the relative importance of the different JBS genes in a Northern European population. Mutations in C5orf42 are relatively frequent (possibly due to a Dutch founder mutation) and mutations in CEP290 are underrepresented compared with international cohorts. Furthermore, we report a case with heterozygous mutations in CC2D2A and B9D1, a gene associated with the more severe Meckel-Gruber syndrome that was recently published as a potential new JBS gene, and discuss the significance of this finding.


Assuntos
Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/genética , Cerebelo/anormalidades , Anormalidades do Olho/diagnóstico , Anormalidades do Olho/genética , Aconselhamento Genético , Doenças Renais Císticas/diagnóstico , Doenças Renais Císticas/genética , Patologia Molecular , Retina/anormalidades , Anormalidades Múltiplas/epidemiologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Adolescente , Criança , Pré-Escolar , Anormalidades do Olho/epidemiologia , Feminino , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lactente , Doenças Renais Císticas/epidemiologia , Masculino , Proteínas de Membrana/genética , Proteínas/genética , Adulto Jovem
15.
Cilia ; 4: 8, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26034581

RESUMO

BACKGROUND: Ciliopathies give rise to a multitude of organ-specific pathologies; obtaining relevant primary patient material is useful for both diagnostics and research. However, acquisition of primary ciliated cells from patients, particularly pediatric patients, presents multiple difficulties. Biopsies and blood samples are invasive, and patients (and their parents) may be reluctant to travel to medical centers, especially for research purposes. We sought to develop non-invasive methods of obtaining viable and ciliated primary cells from ciliopathy patients which could be obtained in the home environment. FINDINGS: We introduce two methods for the non-invasive acquisition of primary ciliated cells. In one approach, we collected spontaneously shed deciduous (milk) teeth from children. Fibroblast-like cells were observed after approximately 2 weeks of culture of fragmented teeth. Secondly, urine samples were collected from children or adults. Cellular content was isolated and after approximately 1 week, renal epithelial cells were observed. Both urine and tooth-derived cells ciliate and express ciliary proteins visible with immunofluorescence. Urine-derived renal epithelial cells (URECs) are amenable to 3D culturing, siRNA knockdown, and ex vivo drug testing. CONCLUSIONS: As evidence continues to accumulate showing that the primary cilium has a central role in development and disease, the need for readily available and ciliated patient cells will increase. Here, we introduce two methods for the non-invasive acquisition of cells with primary cilia. We believe that these cells can be used for further ex vivo study of ciliopathies and in the future, for personalized medicine.

16.
Proc Natl Acad Sci U S A ; 111(27): 9893-8, 2014 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-24946806

RESUMO

Nephronophthisis (NPHP) is the major cause of pediatric renal failure, yet the disease remains poorly understood, partly due to the lack of appropriate animal models. Joubert syndrome (JBTS) is an inherited ciliopathy giving rise to NPHP with cerebellar vermis aplasia and retinal degeneration. Among patients with JBTS and a cerebello-oculo-renal phenotype, mutations in CEP290 (NPHP6) are the most common genetic lesion. We present a Cep290 gene trap mouse model of JBTS that displays the kidney, eye, and brain abnormalities that define the syndrome. Mutant mice present with cystic kidney disease as neonates. Newborn kidneys contain normal amounts of lymphoid enhancer-binding factor 1 (Lef1) and transcription factor 1 (Tcf1) protein, indicating normal function of the Wnt signaling pathway; however, an increase in the protein Gli3 repressor reveals abnormal Hedgehog (Hh) signaling evident in newborn kidneys. Collecting duct cells from mutant mice have abnormal primary cilia and are unable to form spheroid structures in vitro. Treatment of mutant cells with the Hh agonist purmorphamine restored normal spheroid formation. Renal epithelial cells from a JBTS patient with CEP290 mutations showed similar impairments to spheroid formation that could also be partially rescued by exogenous stimulation of Hh signaling. These data implicate abnormal Hh signaling as the cause of NPHP and suggest that Hh agonists may be exploited therapeutically.


Assuntos
Doenças Cerebelares/metabolismo , Anormalidades do Olho/metabolismo , Proteínas Hedgehog/metabolismo , Doenças Renais Císticas/congênito , Retina/anormalidades , Transdução de Sinais , Anormalidades Múltiplas , Animais , Cerebelo/anormalidades , Imunofluorescência , Doenças Renais Císticas/metabolismo , Doenças Renais Císticas/terapia , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Nucleares/genética , Retina/metabolismo
17.
Clin Dysmorphol ; 20(3): 136-42, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21527849

RESUMO

We describe two patients with severe developmental delay, hypotonia and breathing abnormalities initially diagnosed with the autosomal recessive Joubert syndrome (JBS) who at a later stage appeared to carry chromosomal abnormalities. One case was due to a 4.8 Mb terminal 1q44 deletion, and the other due to a 15.5 Mb duplication of Xq27.2-qter containing the MECP2 gene. Critical evaluation of the clinical data showed that, retrospectively, the cases did not fulfil the diagnostic criteria for JBS, and that the diagnosis of JBS was incorrectly made. We discuss the diagnostic pitfalls and recommend adhering strictly to the JBS diagnostic criteria in the case of a negative molecular diagnosis. Critical assessment of the MRI findings by a specialized neuroradiologist is imperative. As chromosomal abnormalities may give rise to symptoms resembling JBS, we recommend array-based screening for segmental aneuploidies as an initial genetic test in all cases with a JBS-like phenotype.


Assuntos
Doenças Cerebelares/diagnóstico , Doenças Cerebelares/genética , Aberrações Cromossômicas , Erros de Diagnóstico , Anormalidades do Olho/diagnóstico , Anormalidades do Olho/genética , Doenças Renais Císticas/diagnóstico , Doenças Renais Císticas/genética , Anormalidades Múltiplas , Cerebelo/anormalidades , Pré-Escolar , Cromossomos Humanos Par 1/genética , Cromossomos Humanos Par 13/genética , Cromossomos Humanos X/genética , Humanos , Lactente , Cariotipagem , Imagem por Ressonância Magnética , Masculino , Proteína 2 de Ligação a Metil-CpG/genética , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Retina/anormalidades
18.
Invest Ophthalmol Vis Sci ; 52(5): 2227-39, 2011 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-21217109

RESUMO

PURPOSE: To determine the genetic defects underlying autosomal recessive retinitis pigmentosa (arRP) in the Dutch population and in a subset of patients originating from other countries. The hypothesis was that, because there has been little migration over the past centuries in certain areas of The Netherlands, a significant fraction of Dutch arRP patients carry their genetic defect in the homozygous state. METHODS: High-resolution genome-wide SNP genotyping on SNP arrays and subsequent homozygosity mapping were performed in a large cohort of 186 mainly nonconsanguineous arRP families living in The Netherlands. Candidate genes residing in homozygous regions were sequenced. RESULTS: In ~94% of the affected individuals, large homozygous sequences were identified in their genome. In 42 probands, at least one of these homozygous regions contained one of the 26 known arRP genes. Sequence analysis of the corresponding genes in each of these patients revealed 21 mutations and two possible pathogenic changes, 14 of which were novel. All mutations were identified in only a single family, illustrating the genetic diversity within the Dutch population. CONCLUSIONS: This report demonstrates that homozygosity mapping is a powerful tool for identifying the genetic defect underlying genetically heterogeneous recessive disorders like RP, even in populations with little consanguinity.


Assuntos
Mapeamento Cromossômico , Estudo de Associação Genômica Ampla/métodos , Homozigoto , Mutação/genética , Polimorfismo de Nucleotídeo Único , Retinite Pigmentosa/genética , Consanguinidade , Análise Mutacional de DNA , Genes Recessivos , Genótipo , Humanos , Análise em Microsséries , Países Baixos , Reação em Cadeia da Polimerase
19.
Invest Ophthalmol Vis Sci ; 52(1): 324-33, 2011 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-20881294

RESUMO

PURPOSE: Anterior segment dysgenesis (ASD) comprises a heterogeneous group of developmental abnormalities that affect several structures of the anterior segment of the eye. The main purpose of this study was to assess the proportion of FOXC1 and PITX2 mutations and copy number changes in 80 probands with ASD. METHODS: The patients were examined for FOXC1 and PITX2 copy number changes and mutations using MLPA (multiplex ligation-dependent probe amplification) and direct sequencing. Subsequently, the identified copy number changes were fine-mapped using high-resolution microarrays. In the remaining mutation-negative patients, sequencing of the FOXC1 andPITX2 3' untranslated regions (UTRs) and three other candidate genes (P32, PDP2, and FOXC2) was performed. RESULTS: Thirteen FOXC1 and eight PITX2 mutations were identified, accounting for 26% (21/80) of the cases. In addition, six FOXC1 and five PITX2 deletions were found, explaining 14% (11/80) of the cases. The smallest FOXC1 and PITX2 deletions were 5.4 and 1.6 kb in size, respectively. Six patients carrying FOXC1 deletions presented with variable extraocular phenotypic features such as hearing defects (in 4/6) and mental retardation (in 2/6). No further genetic defects were found in the remaining mutation-negative patients. CONCLUSIONS: FOXC1 and PITX2 genetic defects explain 40% of our large ASD cohort. The current spectrum of intragenic FOXC1 and PITX2 mutations was extended considerably, the identified copy number changes were fine mapped, the smallest FOXC1 and PITX2 deletions reported so far were identified, and the need for dedicated copy number screening of the FOXC1 and PITX2 genomic landscape was emphasized. This study is unique in that sequence and copy number changes were screened simultaneously in both genes.


Assuntos
Segmento Anterior do Olho/anormalidades , Anormalidades do Olho/genética , Fatores de Transcrição Forkhead/genética , Dosagem de Genes/genética , Proteínas de Homeodomínio/genética , Mutação , Fatores de Transcrição/genética , Regiões 3' não Traduzidas , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Mitocondriais/genética , Técnicas de Amplificação de Ácido Nucleico , Reação em Cadeia da Polimerase
20.
Ophthalmology ; 118(1): 160-167.e1-3, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20801516

RESUMO

PURPOSE: To develop a high-throughput, cost-effective diagnostic strategy for the identification of known and new mutations in 90 retinal disease genes. DESIGN: Evidence-based study. PARTICIPANTS: Sixty patients with a variety of retinal disorders, including Leber's congenital amaurosis, ocular albinism, pseudoxanthoma elasticum, retinitis pigmentosa, and Stargardt's disease. METHODS: We designed a custom 300-kb resequencing chip. Polymerase chain reaction (PCR) amplification, DNA fragmentation, and chip hybridization were performed according to Affymetrix recommendations. Hybridization signals were analyzed using Sequence pilot module seq-C mutation detection software (2009). This resequencing approach was validated by Sanger sequence technology. MAIN OUTCOME MEASURES: Disease-causing sequence changes. RESULTS: We developed a retinal resequencing chip that covers all exons of 90 retinal disease genes. We developed and tested multiplex primer sets for 1445 amplicons representing the genes included on the chip. We validated our approach by screening 87 exons from 25 retinal disease genes containing 87 known sequence changes previously identified in our patient group using Sanger sequencing. Call rates for successfully hybridized amplicons were 98% to 100%. Of the known single nucleotide changes, 99% could be detected on the chip. As expected, deletions could not be detected reliably. CONCLUSIONS: We designed a custom resequencing chip that can detect known and new sequence changes in 90 retinal disease genes using a new high-throughput strategy with a high sensitivity and specificity for one tenth of the cost of conventional direct sequencing. The developed amplification strategy allows for the pooling of multiple patients with non-overlapping phenotypes, enabling many patients to be analyzed simultaneously in a fast and cost-effective manner.


Assuntos
Análise Mutacional de DNA/métodos , Proteínas do Olho/genética , Mutação , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Doenças Retinianas/genética , Análise Custo-Benefício , Análise Mutacional de DNA/economia , Humanos , Análise de Sequência com Séries de Oligonucleotídeos/economia , Reação em Cadeia da Polimerase , Polimorfismo de Nucleotídeo Único , Sensibilidade e Especificidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA