RESUMO
Retinitis pigmentosa (RP) is an inherited retinal dystrophy caused by the loss of photoreceptors and retinal pigment epithelial atrophy, leading to severe visual impairment or blindness. RP can be classified as nonsyndromic or syndromic with complex clinical phenotypes. Three unrelated Polish probands affected with retinitis pigmentosa coexisting with cerebellar ataxia were recruited for this study. Clinical heterogeneity and delayed appearance of typical disease symptoms significantly prolonged the patients' diagnostic process. Therefore, many clinical and genetic tests have been performed in the past. Here, we provide detailed clinical and genetic analysis results of the patients. Whole-exome sequencing (WES) and targeted NGS analysis allow the identification of four novel and two previously reported variants in the following genes: ABHD12, FLVCR1, and PNPLA6. The use of next-generation sequencing (NGS) methods finally allowed for confirmation of the clinical diagnosis. Ultra-rare diseases such as PHARC, PCARP, and Oliver-McFarlane syndromes were diagnosed in patients, respectively. Our findings confirmed the importance of the application of next-generation sequencing methods, especially in ultra-rare genetic disorders with overlapping features.
Assuntos
Sequenciamento do Exoma , Retinose Pigmentar , Humanos , Retinose Pigmentar/genética , Retinose Pigmentar/diagnóstico , Masculino , Feminino , Linhagem , Sequenciamento de Nucleotídeos em Larga Escala , Adulto , Ataxia Cerebelar/genética , Ataxia Cerebelar/diagnóstico , Proteínas de Membrana Transportadoras/genética , Monoacilglicerol Lipases/genética , Mutação , Ataxia/genética , Ataxia/diagnóstico , Fenótipo , Aciltransferases , Catarata , Fosfolipases , PolineuropatiasRESUMO
Leber hereditary optic neuropathy (LHON) is a rare disorder causing a sudden painless loss of visual acuity in one or both eyes, affecting young males in their second to third decade of life. The molecular background of the LHON is up to 90%, genetically defined by a point mutation in mitochondrial DNA. Recently, an autosomal recessive form of LHON (LHONAR1, arLHON) has been discovered, caused by biallelic variants in the DNAJC30 gene. This study provides the results of the DNAJC30 gene analysis in a large group of 46 Polish patients diagnosed with LHON, together with the clinical characterization of the disease. The c.152A>G (p.Tyr51Cys) substitution in the DNAJC30 gene was detected in all the patients as homozygote or compound heterozygote. Moreover, we identified one novel variant, c.293A>G, p.(Tyr98Cys), as well as two ultra-rare DNAJC30 variants: c.293A>C, p.(Tyr98Ser), identified to date only in one individual affected with LHONAR1, and c.130_131delTC (p.Ser44ValfsTer8), previously described only in two patients with Leigh syndrome. The patients presented here represent the largest group of subjects with DNAJC30 gene mutations described to date. Based on our data, the autosomal recessive form of LHON caused by DNAJC30 gene mutations is more frequent than the mitochondrial form in Polish patients. The results of our study suggest that Sanger sequencing of the single-exon DNAJC30 gene should be a method of choice applied to identify a molecular background of clinically confirmed LHON in Polish patients. This approach will help to reduce the costs of molecular testing.
Assuntos
Proteínas de Choque Térmico HSP40 , Atrofia Óptica Hereditária de Leber , Humanos , Masculino , DNA Mitocondrial/genética , Mitocôndrias/genética , Mutação , Atrofia Óptica Hereditária de Leber/genética , Polônia , Doenças Raras/genética , Proteínas de Choque Térmico HSP40/genéticaRESUMO
Aniridia is usually an autosomal dominant, rare disorder characterized by a variable degree of hypoplasia or the absence of iris tissue, with additional ocular abnormalities. Pathogenic variants in the PAX6 gene are associated with aniridia in most patients. However, in up to 30% of individuals, disease results from 11p13 chromosomal rearrangements. Here we present a patient with a clinical diagnosis of partial aniridia born to consanguineous Polish parents. The parents were asymptomatic and ophthalmologically normal. We performed PAX6 sequencing, array comparative genomic hybridization, quantitative real-time PCR, and whole genome sequencing. aCGH revealed a homozygous deletion of the DCDC1 gene fragment in the patient. The same, but heterozygous deletion, was detected in each of the patient's asymptomatic parents and brother. In the presented family, the signs and symptoms of aniridia are observed only in the homozygous proband. Whole genome sequencing analysis was performed to determine other possible causes of the disease and did not detect any additional or alternative potentially pathogenic variant. We report a novel homozygous deletion located in the 11p13 region, which does not include the PAX6 gene or any known PAX6 enhancers. To our best knowledge, this is the first reported case of a patient presented with isolated aniridia carrying a homozygous microdeletion downstream of the PAX6 gene.
Assuntos
Aniridia , Proteínas do Olho , Aniridia/diagnóstico , Aniridia/genética , Hibridização Genômica Comparativa , Proteínas do Olho/genética , Proteínas de Homeodomínio/genética , Homozigoto , Humanos , Masculino , Fator de Transcrição PAX6/genética , Linhagem , Deleção de SequênciaRESUMO
Cranioectodermal dysplasia (CED) is rare heterogeneous condition. It belongs to a group of disorders defined as ciliopathies and is associated with defective cilia function and structure. To date six genes have been associated with CED. Here we describe a 4-year-old male CED patient whose features include dolichocephaly, multi-suture craniosynostosis, epicanthus, frontal bossing, narrow thorax, limb shortening, and brachydactyly. The patient presented early-onset chronic kidney disease and was transplanted at the age of 2 years and 5 months. At the age of 3.5 years a retinal degeneration was diagnosed. Targeted sequencing by NGS revealed the presence of compound heterozygous variants in the WDR35 gene. The variants are a novel missense change in exon 9 p.(Gly303Arg) and a previously described nonsense variant in exon 18 p.(Leu641*). Our findings suggest that patients with WDR35 defects may be at risk to develop early-onset retinal degeneration. Therefore, CED patients with pathogenic variation in this gene should be assessed at least once by the ophthalmologist before the age of 4 years to detect early signs of retinal degeneration.
Assuntos
Craniossinostoses , Falência Renal Crônica , Distrofias Retinianas , Osso e Ossos/anormalidades , Pré-Escolar , Craniossinostoses/complicações , Craniossinostoses/diagnóstico , Craniossinostoses/genética , Proteínas do Citoesqueleto/genética , Nanismo , Displasia Ectodérmica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Mutação , Osteocondrodisplasias , Distrofias Retinianas/diagnóstico , Distrofias Retinianas/genéticaRESUMO
Anophthalmia and microphthalmia (A/M) represent severe developmental ocular malformations, corresponding, respectively, to absent eyeball or reduced size of the eye. Both anophthalmia and microphthalmia may occur in isolation or as part of a syndrome. Genetic heterogeneity has been demonstrated, and many genes have been reported to be associated with A/M. The advances in high-throughput sequencing have proven highly effective in defining the molecular basis of A/M. Nevertheless, there are still many patients with unsolved genetic background of the disease, who pose a significant challenge in the molecular diagnostics of A/M. Here we describe a family, with three males affected with the non-syndromic A/M. Whole exome-sequencing performed in Patient 1, revealed the presence of a novel probably pathogenic variant c.734A>G, (p.[Tyr245Cys]) in the PORCN gene. Pedigree analysis and segregation of the identified variant in the family confirmed the X-linked recessive pattern of inheritance. This is the first report of X-linked recessive non-syndromic A/M. Until now, pathogenic variants in the PORCN gene have been identified in the patients with Goltz syndrome, but they were inherited in X-linked dominant mode. The ocular phenotype is the only finding observed in the patients, which allows to exclude the diagnosis of Goltz syndrome.
Assuntos
Aciltransferases/genética , Anoftalmia/genética , Predisposição Genética para Doença , Proteínas de Membrana/genética , Microftalmia/genética , Adulto , Anoftalmia/complicações , Anoftalmia/patologia , Pré-Escolar , Exoma/genética , Feminino , Hipoplasia Dérmica Focal/genética , Hipoplasia Dérmica Focal/patologia , Genes Recessivos/genética , Genes Ligados ao Cromossomo X/genética , Heterogeneidade Genética , Humanos , Lactente , Masculino , Microftalmia/complicações , Microftalmia/patologia , Mutação/genética , Linhagem , Fenótipo , Sequenciamento do ExomaRESUMO
Cranioectodermal dysplasia (CED) is a rare autosomal recessive disorder primarily characterized by craniofacial, skeletal, and ectodermal abnormalities. CED is a chondrodysplasia, which is part of a spectrum of clinically and genetically heterogeneous diseases that result from disruptions in cilia. Pathogenic variants in genes encoding components of the ciliary transport machinery are known to cause CED. Intra- and interfamilial clinical variability has been reported in a few CED studies and the findings of this study align with these observations. Here, we report on five CED patients from four Polish families with identical compound heterozygous variants [c.1922T>G p.(Leu641Ter) and c.2522A>T; p.(Asp841Val)] in WDR35. The frequent occurrence of both identified changes in Polish CED families suggests that these variants may be founder mutations. Clinical evaluation of the CED patients revealed interfamilial clinical variability among the patients. This includes differences in skeletal and ectodermal features as well as variability in development, progression, and severity of renal and liver insufficiency. This is the first report showing significant interfamilial clinical variability in a series of CED patients from unrelated families with identical compound heterozygous variants in WDR35. Our findings strongly indicate that other genetic and non-genetic factors may modulate the progression and expression of the patients' phenotypes.
Assuntos
Osso e Ossos/anormalidades , Craniossinostoses/genética , Proteínas do Citoesqueleto/genética , Displasia Ectodérmica/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Osso e Ossos/patologia , Criança , Pré-Escolar , Cílios/genética , Cílios/patologia , Craniossinostoses/epidemiologia , Craniossinostoses/patologia , Displasia Ectodérmica/epidemiologia , Displasia Ectodérmica/patologia , Feminino , Humanos , Lactente , Masculino , Mutação/genética , Linhagem , Fenótipo , Polônia/epidemiologiaRESUMO
The ciliary chondrodysplasias represent a group of clinically and genetically heterogeneous disorders that affect skeleton development. Cilia are organelles that project from the surface of many cell types and play an important role during prenatal and postnatal human development. Cranioectodermal dysplasia (Sensenbrenner syndrome, CED) is a ciliopathy primarily characterized by craniofacial, skeletal, and ectodermal abnormalities. To date six genes have been associated with CED: IFT122, WDR35, WDR19, IFT140, IFT43, and IFT52. Prenatal diagnosis of CED is challenging, and genetic testing can facilitate making a correct diagnosis. Here, we report on a family with two male siblings affected by CED: a 3.5 year-old patient and his 2 year-old brother. Molecular analysis of the proband at 1 year of age revealed compound heterozygous variants in WDR35: c.3G>A [p.(Met1-Ala30delinsMetfsTer4)] and c.2522A>T [p.(Asp841Val)]. Ultrasound examination during the second pregnancy revealed an increased nuchal translucency of 4.5 mm and a hypoplastic nasal bone at 12 weeks of gestation. Prenatal diagnostic testing was offered because of an increased risk for chromosomal abnormalities and recurrence risk for CED. Prenatal genetic analysis of a chorionic villus sample detected the WDR35 variants previously identified in the elder brother. This is the first report of a prenatal genetic diagnosis in CED.
Assuntos
Osso e Ossos/anormalidades , Craniossinostoses/diagnóstico , Proteínas do Citoesqueleto/genética , Displasia Ectodérmica/diagnóstico , Peptídeos e Proteínas de Sinalização Intracelular/genética , Diagnóstico Pré-Natal , Osso e Ossos/patologia , Pré-Escolar , Craniossinostoses/genética , Craniossinostoses/patologia , Displasia Ectodérmica/genética , Displasia Ectodérmica/patologia , Feminino , Heterozigoto , Humanos , Lactente , Masculino , Polônia/epidemiologiaRESUMO
Purpose: The aim of this study was to identify the molecular genetic basis of cone-rod dystrophy in 18 unrelated families of Polish origin. Cone-rod dystrophy is one of the inherited retinal dystrophies, which constitute a highly heterogeneous group of disorders characterized by progressive dysfunction of photoreceptors and retinal pigment epithelium (RPE) cells. Methods: The study group was composed of four groups of patients representing different Mendelian inheritance of the disease: autosomal dominant (AD), autosomal recessive (AR), X-linked recessive (XL), and autosomal recessive or X-linked recessive (AR/XL). The combined molecular strategy included Sanger sequencing of the RPGR-ORF15 gene (three families with XL and three families with the AR/XL mode of inheritance), mutation-specific microarray analysis of the ABCA4 gene (five families with the AR mode of inheritance and two families with the AR/XL mode of inheritance), targeted next-generation sequencing (NGS) of inherited retinal disease-associated (IRD) genes (seven families with the AD mode of inheritance and five families with the AR mode of inheritance), and whole exome sequencing, performed in select families who had been mutation-negative in the analysis with the targeted NGS panel (one family with the AD mode of inheritance, one family with the AR mode of inheritance, and two families with the AR/XL mode of inheritance). Results: Based on this combined strategy, we managed to identify potentially causative variants in seven out of 18 families with CRD. Five of these variants are novel: c.3142_3143dupAA, p.(Glu1049Argfs*41) in the RPGR-ORF15 gene, two variants: c.1612delT, p.(Trp538Glyfs*15) and c.2389dupG, p.(Ile798Hisfs*20) in the PROM1 gene in one family, c.592A>C, p.(Ser198Arg) in the PRPH2 gene and the variant c.1691A>G, p.(Asp564Gly) in the ATF6 gene that we have already reported to be pathogenic. NGS on the IRD panel allowed the molecular basis of CRD to be identified in four out of 14 families with a total detection rate of 38%. WES allowed identification of the molecular genetic basis of CRD in one family. Conclusions: This is the first report on the spectrum of disease genes and pathogenic variants causing CRD in the Polish population. The study presents five novel variants identified in four genes and therefore, broadens the spectrum of probable pathogenic variants associated with CRD.
Assuntos
Antígeno AC133/genética , Transportadores de Cassetes de Ligação de ATP/genética , Fator 6 Ativador da Transcrição/genética , Transtornos Cromossômicos/genética , Distrofias de Cones e Bastonetes/genética , Proteínas do Olho/genética , Doenças Genéticas Ligadas ao Cromossomo X/genética , Periferinas/genética , Adolescente , Adulto , Transtornos Cromossômicos/diagnóstico , Transtornos Cromossômicos/patologia , Estudos de Coortes , Distrofias de Cones e Bastonetes/diagnóstico , Distrofias de Cones e Bastonetes/patologia , Feminino , Expressão Gênica , Genes Dominantes , Genes Recessivos , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico , Doenças Genéticas Ligadas ao Cromossomo X/patologia , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Polônia , Polimorfismo Genético , Epitélio Pigmentado da Retina/metabolismo , Epitélio Pigmentado da Retina/patologia , Análise de Sequência de DNARESUMO
Sensenbrenner syndrome (cranioectodermal dysplasia, CED) is a very rare autosomal recessive ciliopathy. Cranioectodermal dysplasia is characterized by craniofacial, skeletal, and ectodermal abnormalities. About 50 patients have been described to date. Sensenbrenner syndrome belongs to a group of ciliary chondrodysplasias and is a genetically heterogeneous disorder. Mutations in five genes: IFT122, WDR35, IFT43, WDR19, and IFT52 have been associated with CED. All known genes encode proteins that are part of the intraflagellar transport complex, which plays an important role in the assembly and maintenance of cilia. Here, we report a family with two children affected by Sensenbrenner syndrome, a 9-year-old girl and her older sister who died in infancy due to respiratory, liver, and renal insufficiency. Dysmorphic features included short stature with rhizomelic shortening of limbs, short fingers, preaxial polydactyly of left hand, narrow chest, craniosynostosis, dolichocephaly, high anterior hairline, epicanthal folds and telecanthus, depressed nasal bridge, low-set ears, and additional ectodermal abnormalities. The patient presented with chronic tubulointerstitial renal disease. She had abnormal echogenicity on renal ultrasound, reduced glomerular filtration, albuminuria and tubular proteinuria, hypocalciuria and hypocitraturia, accompanied by pre-hypertensive state. This pattern of renal abnormality was regarded as nephronophthisis. Psychomotor development was apparently normal. Molecular analysis in one of the affected individuals identified compound heterozygosity for a nonsense (c.1922T>G, p.(Leu641*)) and missense (c.2522A>T, p.(Asp841Val)) variants in WDR35. We present a detailed clinical descriptions of two female siblings showing an intrafamilial phenotypic variability of the disease, and illustrating the potential lethality of CED.
Assuntos
Osso e Ossos/anormalidades , Craniossinostoses/genética , Displasia Ectodérmica/genética , Proteínas/genética , Alelos , Osso e Ossos/fisiopatologia , Criança , Cílios/genética , Cílios/patologia , Códon sem Sentido , Craniossinostoses/fisiopatologia , Proteínas do Citoesqueleto , Displasia Ectodérmica/fisiopatologia , Feminino , Proteínas Hedgehog , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Rim/fisiopatologia , Mutação de Sentido Incorreto , Polônia , IrmãosRESUMO
Jalili syndrome is a rare disorder inherited in an autosomal recessive pattern manifesting as a combination of cone-rod dystrophy including progressive loss of visual acuity, color blindness, photophobia, and amelogenesis imperfecta with hypoplastic, immature, or hypocalcified dental enamel. It is caused by mutations in CNNM4, which encodes the ancient conserved domain protein 4. Here we report three brothers with Jalili syndrome and muscle overgrowth of the legs. Myopathic changes were found in needle electromyography. Mutational analysis showed in all three brothers a novel likely pathogenic homozygous missense substitution in exon 1 (c.1076T>C, p.(Leu359Pro)) of CNNM4. Both parents were carriers for the variant. In order to exclude other causative variants that could modify the patients' phenotype we performed exome sequencing and MLPA analysis of the DMD gene in Patient 1. These analyses did not identify any additional variants. Our results expand the mutational spectrum associated with Jalili syndrome and suggest that mild myopathy with muscle overgrowth of the legs could be a newly identified manifestation of the disorder.
Assuntos
Amelogênese Imperfeita/genética , Proteínas de Transporte de Cátions/genética , Distrofias de Cones e Bastonetes/genética , Retinose Pigmentar/genética , Amelogênese Imperfeita/fisiopatologia , Distrofias de Cones e Bastonetes/fisiopatologia , Consanguinidade , Distrofina/genética , Eletromiografia , Éxons , Homozigoto , Humanos , Masculino , Mutação , Linhagem , Fenótipo , Retinose Pigmentar/fisiopatologia , Acuidade Visual/genéticaRESUMO
Background: Molecular analysis of the NDP gene to confirm and precise the clinical diagnosis in two patients with X-linked familial exudative vitreoretinopathy (XL-FEVR). Material and methods: We report two patients from unrelated families with NDP gene mutations: a 14-month-old boy (p1) who was found to have severe exudative vitreoretinopathy and a 4-year-old boy with exudative vitreoretinopathy (p2). An extensive clinical examination of the probands, including slit-lamp examination, B-mode ultrasonography and magnetic resonance imaging was conducted, along with genetic analysis of NDP gene. Results: Clinical findings in patient 1 included no light perception, total retinal detachment and hyperplastic primary vitreous in both eyes. The genetic analysis of the NDP gene enabled to identify the novel frameshift mutation c.222_c223insCG in p1 leading to the premature stop codon and production of aberrant norrin protein. In P2, clinical presentation included high myopia with astigmatism, unilateral fibrous bands and retinal detachment. Genetic testing revealed known point mutation c.362G>A leading to amino-acid alteration and improper protein. Conclusions: Mutation screening of NDP gene identified two different mutations in this region, one of which has not been previously reported.
Assuntos
Cegueira/congênito , Proteínas do Olho/genética , Doenças Genéticas Ligadas ao Cromossomo X/genética , Proteínas do Tecido Nervoso/genética , Doenças do Sistema Nervoso/genética , Doenças Retinianas/genética , Espasmos Infantis/genética , Cegueira/genética , Pré-Escolar , Análise Mutacional de DNA , Oftalmopatias Hereditárias , Vitreorretinopatias Exsudativas Familiares , Genes Ligados ao Cromossomo X , Testes Genéticos , Humanos , Masculino , Degeneração RetinianaRESUMO
UNLABELLED: Oguchi disease type 2 is a rare autosomal recessive form of congenital stationary night blindness. A typical feature of this disorder is a golden-brown discoloration of the fundus called Mizuo-Nakamura phenomenon, which disappears after prolonged dark adaptation and reappears shortly after the onset of light. MATERIAL AND METHODS: A 13-year-old boy exhibiting the clinical features of congenital stationary night blindness, was examined. Ophthalmic examination including slit-lamp biomicroscopy, perimetry and funduscopy was performed. Additionally, the full-field electroretinography and molecular testing for congenital stationary night blindness using the Single Nucleotide Polymorphism microarray technique were performed. RESULTS: The ophthalmic examination showed normal visual acuity, normal anterior segment of both eyes and full visual fields. The eye fundus examination showed a typical golden-brownish discoloration of the peripheral retina (disappearing after long dark adaptation) with no pigment deposits. Full-field electroretinography showed reduced amplitudes of both waves under scotopic conditions, while under photopic conditions both shape and parameters of the record were within the normal limits. The Single Nucleotide Polymorphism microarray revealed a homozygous deletion: c.1607161 OdelCGGA in GRK1 gene. This frameshift mutation introduces a stop codon (p.Asp537Valfs*542) and results in deletion of terminal 22 amino acid residues of retinal kinase protein. CONCLUSIONS: This is the first molecular evidence for GRK1 gene mutation in a Polish patient with Oguchi disease type 2. The identification of the c.1607_1610delCGGA mutation in a patient with Oguchi disease confirms the pathogenicity of this variant.
Assuntos
Adaptação à Escuridão/genética , Receptor Quinase 1 Acoplada a Proteína G/genética , Mutação de Sentido Incorreto , Cegueira Noturna/genética , Adolescente , Análise Mutacional de DNA , Eletrorretinografia , Humanos , Masculino , Cegueira Noturna/diagnóstico , Reação em Cadeia da Polimerase , Acuidade Visual , Campos VisuaisRESUMO
PURPOSE: To identify the genetic basis of achromatopsia (ACHM) in four patients from four unrelated Polish families. METHODS: In this study, we investigated probands with a clinical diagnosis of ACHM. Ophthalmologic examinations, including visual acuity testing, color vision testing, and full-field electroretinography (ERG), were performed in all patients (with the exception of patient p4, who had no ERG). Direct DNA sequencing encompassing the entire coding region of the CNGB3 gene, eight exons of the GNAT2 gene, and exons 5-7 of the CNGA3 gene was performed. Segregation analysis for the presence and independent inheritance of two mutant alleles was performed in the three families available for study. RESULTS: All patients showed typical achromatopsia signs and symptoms. Sequencing helped detect causative changes in the CNGB3 gene in all probands. Eight different mutations were detected in the CNGB3 gene, including five novel mutations: two splice site mutations (c.1579-1G>A and c.494-2A>T), one nonsense substitution (c.1194T>G), and two frame-shift mutations (c.393_394delGCinsTCCTGGTGA and c.1366delC). We also found three mutations: one splice site (c.1578+1G>A) and two frame-shift deletions that had been previously described (c.819_826del and c.1148delC). All respective parents were shown to be heterozygous carriers for the mutation detected in their children. CONCLUSIONS: The present study reports five novel mutations in the CNGB3 gene, and thus broadens the spectrum of probably pathogenic mutations associated with ACHM. Together with molecular data, we provide a brief clinical description of the affected individuals.
Assuntos
Defeitos da Visão Cromática/genética , Canais de Cátion Regulados por Nucleotídeos Cíclicos/genética , Mutação , Adulto , Sequência de Bases , Criança , Códon sem Sentido , Defeitos da Visão Cromática/fisiopatologia , Análise Mutacional de DNA , Eletrorretinografia , Feminino , Mutação da Fase de Leitura , Humanos , Masculino , Linhagem , Polônia , Sítios de Splice de RNA , Deleção de SequênciaRESUMO
Aniridia, which is a rare congenital defect of the eye, consists of iris hypoplasia or aplasia, and additional ocular abnormalities. It is most commonly caused by autosomal dominant PAX6 gene mutations. However, in about 30% of cases, it is associated with chromosomal rearrangements in the 11p13 region. The aim of this study was to identify the potential PAX6 gene variants, which could cause the isolated aniridia. Eight patients with isolated aniridia were included in this study. MLPA analysis allowed in the past to exclude large structural rearrangements of the PAX6 and adjacent genes like WT1. Blood samples were collected from the patients (and their families in familial cases) and genomic DNA was extracted from peripheral blood leukocytes and buccal cells. The amplification of the 11 exons of the PAX6 gene was performed. Bidirectional Sanger Sequencing was conducted for the identification of the potentially pathogenic variants, and for the segregation analysis of the identified variant in the family. The results were analyzed with the use of CodonCode Aligner software. In three patients, aniridia was sporadic, whereas in another five cases, the eye defect was familial. The potentially pathogenic variants in the PAX6 gene were found in 6 out of 8 patients with aniridia. We identified four known (c.781C > T, c.607C > T, and c.949C > T twice), and two novel variants (c.258_265del and c.495_496insG). Point mutations in the PAX6 gene are the most frequent cause of aniridia. The investigation of the genetic background of the disease is essential for patients to evaluate recurrence risk in the offspring.
Assuntos
Aniridia , Anormalidades do Olho , Humanos , Fator de Transcrição PAX6/genética , Fatores de Transcrição Box Pareados/genética , Mucosa Bucal/patologia , Aniridia/diagnóstico , Aniridia/genética , Aniridia/patologia , Anormalidades do Olho/genética , Mutação , Proteínas de Homeodomínio/genética , LinhagemRESUMO
Leber congenital amaurosis (LCA) is the most severe form of inherited retinal dystrophies and the most frequent cause of congenital blindness in children. To date, 25 genes have been implicated in the pathogenesis of this rare disorder. Performing an accurate molecular diagnosis is crucial as gene therapy is becoming available. This study aimed to report the molecular basis of Leber congenital amaurosis, especially novel and rare variants in 27 Polish families with a clinical diagnosis of LCA fully confirmed by molecular analyses. Whole exome sequencing or targeted next-generation sequencing (NGS) of inherited retinal dystrophies-associated (IRD) genes was applied to identify potentially pathogenic variants. Bidirectional Sanger sequencing and quantitative PCR (qPCR) were carried out for validation and segregation analysis of the variants identified within the families. We identified 28 potentially pathogenic variants, including 11 novel, in 8 LCA genes: CEP290, CRB1, GUCY2D, NMNAT1, RPGRIP1, CRX, LRAT1, and LCA5. This study expands the mutational spectrum of the LCA genes. Moreover, these results, together with the conclusions from our previous studies, allow us to point to the most frequently mutated genes and variants in the Polish cohort of LCA patients.
Assuntos
Amaurose Congênita de Leber , Nicotinamida-Nucleotídeo Adenililtransferase , Distrofias Retinianas , Criança , Humanos , Amaurose Congênita de Leber/genética , Amaurose Congênita de Leber/diagnóstico , Polônia , Análise Mutacional de DNA , Mutação , Sequenciamento de Nucleotídeos em Larga Escala , Linhagem , Proteínas do Olho/genética , Proteínas do Olho/metabolismo , Proteínas de Membrana/genética , Proteínas do Tecido Nervoso/genética , Nicotinamida-Nucleotídeo Adenililtransferase/genética , Antígenos de Neoplasias/genéticaRESUMO
Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous group of disorders with progressive loss of photoreceptor and pigment epithelial function. Nineteen unrelated Polish probands clinically diagnosed with nonsyndromic RP were recruited to this study. We used whole-exome sequencing (WES) to identify potential pathogenic gene variants in molecularly undiagnosed RP patients, as a molecular re-diagnosis after having performed targeted NGS in the past. Targeted NGS allowed for identification of the molecular background in only 5 out of 19 patients. Fourteen patients who remained unsolved despite the targeted NGS were subjected to WES. WES revealed potentially causative variants in RP-related genes in another 12 patients. Together, NGS methods revealed the coexistence of causal variants affecting distinct RP genes in 17 out of 19 RP families, with a very high efficiency of 89%. With the improvement of NGS methods, including higher sequencing depth, broader target enrichment, and better bioinformatic analysis capabilities, the ratio of identified causal gene variants has significantly increased. Therefore, it is important to consider repeating high-throughput sequencing analysis in those patients in whom the previously performed NGS did not reveal any pathogenic variants. The study confirmed the efficiency and clinical utility of re-diagnosis with WES in molecularly undiagnosed RP patients.
RESUMO
Background: Cranioectodermal dysplasia (CED) is a skeletal autosomal recessive ciliopathy. The characteristic clinical features of CED are facial dysmorphisms, short limbs, narrow thorax, brachydactyly, ectodermal abnormalities, and renal insufficiency. Thus far, variants in six genes are known to be associated with this disorder: WDR35, IFT122, IFT140, IFT144, IFT52, and IFT43. Objective: The goal of this study was to perform cilium phenotyping in human urine-derived renal epithelial cells (hURECs) from a CED patient diagnosed with second-stage chronic kidney disease (CKD) and three unrelated and unaffected pediatric controls. Methods: Genetic analysis by WDR35 screening was performed in the affected individual. Cilium frequency and morphology, including cilium length, height, and width, were evaluated by immunofluorescence (IF) experiments in hURECs using two markers visualizing the ciliary axoneme (Acet-Tub and ARL13B) and the base of the cilium (PCNT). The IF results were analyzed using a confocal microscope and IMARIS software. Results: WDR35 analysis revealed the presence of a known nonsense p. (Leu641*) variant and a novel missense variant p. (Ala1027Thr). Moreover, comparative genomic hybridization analysis showed that the patient carries a microdeletion on chromosome 7q31.1. Ciliary phenotyping performed on hURECs showed morphological differences in the patient's cilia as compared to the three controls. The cilia of the CED patient were significantly wider and longer. Conclusion: The obtained results suggest that CED-related second-stage CKD might be associated with cilia abnormalities, as identified in renal epithelial cells from a CED patient harboring variants in WDR35. This study points out the added value of hURECs in functional testing for ciliopathies.
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Ciliopathies are rare congenital disorders, caused by defects in the cilium, that cover a broad clinical spectrum. A subgroup of ciliopathies showing significant phenotypic overlap are known as skeletal ciliopathies and include Jeune asphyxiating thoracic dysplasia (JATD), Mainzer-Saldino syndrome (MZSDS), cranioectodermal dysplasia (CED), and short-rib polydactyly (SRP). Ciliopathies are heterogeneous disorders with >187 associated genes, of which some genes are described to cause more than one ciliopathy phenotype. Both the clinical and molecular overlap make accurate diagnosing of these disorders challenging. We describe two unrelated Polish patients presenting with a skeletal ciliopathy who share the same compound heterozygous variants in IFT140 (NM_014,714.4) r.2765_2768del; p.(Tyr923Leufs*28) and exon 27-30 duplication; p.(Tyr1152_Thr1394dup). Apart from overlapping clinical symptoms the patients also show phenotypic differences; patient 1 showed more resemblance to a Mainzer-Saldino syndrome (MZSDS) phenotype, while patient 2 was more similar to the phenotype of cranioectodermal dysplasia (CED). In addition, functional testing in patient-derived fibroblasts revealed a distinct cilium phenotyps for each patient, and strikingly, the cilium phenotype of CED-like patient 2 resembled that of known CED patients. Besides two variants in IFT140, in depth exome analysis of ciliopathy associated genes revealed a likely-pathogenic heterozygous variant in INTU for patient 2 that possibly affects the same IFT-A complex to which IFT140 belongs and thereby could add to the phenotype of patient 2. Taken together, by combining genetic data, functional test results, and clinical findings we were able to accurately diagnose patient 1 with "IFT140-related ciliopathy with MZSDS-like features" and patient 2 with "IFT140-related ciliopathy with CED-like features". This study emphasizes that identical variants in one ciliopathy associated gene can lead to a variable ciliopathy phenotype and that an in depth and integrated analysis of clinical, molecular and functional data is necessary to accurately diagnose ciliopathy patients.
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Genetically determined ophthalmic diseases form a numerous and heterogenic group of disorders. Making the accurate clinical diagnosis of genetic eye disease is often a challenge for an ophthalmologist. In many cases, only genetic testing enables the establishment of the proper clinical diagnosis. Here we describe two ultra-rare diseases: gyrate atrophy of the choroid and retina (GACR) and Kjer-type optic atrophy coexisting in a 39-year-old Polish patient with severe visual impairment including a significant reduction of visual acuity and night blindness. Atrophic pigmented changes with large pigment deposits and chorioretinal atrophy with the retina's disturbed structure (with atrophic scarring changes and the epiretinal membrane) of both eyes were observed. Electroretinography (ERG) revealed extinguished responses. A Next-Generation Sequencing (NGS) panel comprising 275 retinal genes revealed a presence of potentially pathogenic variants in two genes: a homozygous variant c.1058G>A (p.Gly353Asp) in the OAT gene and a heterozygous variant c.1886C>G (p.Ser629Ter) in the OPA1 gene. The diagnosis established based on NGS is surprising because initially, several different diagnoses have been made, including high degenerative myopia, choroideremia, Leber congenital amaurosis, and severe, atypical retinitis pigmentosa. This report provides the unquestioned diagnostic value of the combination of chorioretinal imaging and the NGS technique. To our knowledge, this is the first and the only description of the coincidence of gyrate atrophy and Kjer-type optic atrophy.
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PURPOSE: Genetic analysis of two siblings with complex microphthalmia, with clinically healthy parents. STUDY DESIGN: Clinical and experimental. METHODS: The patients underwent a detailed ophthalmic evaluation, including visual acuity, fundus examination, gonioscopy, ultrasound examination, and optical coherence tomography. Lensectomy with anterior vitrectomy was conducted in both patients. Additionally, in patient p1, electroencephalography analysis was performed. Genetic analysis was carried out using array comparative genomic hybridization (aCGH) and whole exome sequencing (WES). Bidirectional Sanger sequencing was conducted for validation and segregation analysis of the identified variant in the family. RESULTS: The aCGH results were normal. The heterozygous PAX6 variant c.52G>C (p.Gly18Arg) was identified in the proband (p1) through WES analysis. Sanger sequencing of exon 5 of PAX6 confirmed the presence of the variant in the other affected sibling (patient p2) but did not allow for identification of the variant in the parents' DNA isolated from leukocytes and buccal cells. CONCLUSIONS: The description of the variant in PAX6 in two siblings with clinically healthy parents who are negative for the mutation in DNA from leukocytes and buccal cells represents the possibility of parental gonadal mosaicism. Detection of germ cell mosaicism in the parents is essential to provide genetic counseling to the family regarding the risk of reoccurrence. Furthermore, we also report a pathogenic variant in PAX6 that to our knowledge has not so far been reported in patients with partial aniridia and therefore broadens the spectrum of the variants associated with aniridia.