FERNANDO KOK
Projetos de Pesquisa
Unidades Organizacionais
Departamento de Neurologia, Faculdade de Medicina - Docente
LIM/45 - Laboratório de Fisiopatologia Neurocirúrgica, Hospital das Clínicas, Faculdade de Medicina
LIM/15 - Laboratório de Investigação em Neurologia, Hospital das Clínicas, Faculdade de Medicina
LIM/45 - Laboratório de Fisiopatologia Neurocirúrgica, Hospital das Clínicas, Faculdade de Medicina
LIM/15 - Laboratório de Investigação em Neurologia, Hospital das Clínicas, Faculdade de Medicina
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- Neurodevelopmental disorder associated with de novo SCN3A pathogenic variants: two new cases and review of the literature(2020) INUZUKA, Luciana Midori; MACEDO-SOUZA, Lucia Ines; DELLA-RIPA, Bruno; CABRAL, Katiane S. S.; MONTEIRO, Fabiola; KITAJIMA, Joao Paulo; GODOY, Luis Filipe de Souza; DELGADO, Daniel de Souza; KOK, Fernando; GARZON, ElianaSCN3A was recently recognized as a gene associated with neurodevelopmental disorder and epilepsy. We present two additional patients with a novel de novo SCN3A pathogenic variant, and a review of all published cases of de novo variants. In one of our patients brain magnetic resonance imaging (MRI) disclosed a severe polymicrogyria and in the other it was normal. The clinical phenotype was characterized by a severe developmental delay and refractory epilepsy in the patient with polymicrogyria and intellectual disability with autistic features and pharmacoresponsive epilepsy in the subject with normal MRI. Polymicrogyria, a disorder of progenitor cells proliferation and migration, is an unanticipated finding for an ion channel dysfunction.
- Homozygous missense mutation in MED25 segregates with syndromic intellectual disability in a large consanguineous family(2015) FIGUEIREDO, Thalita; MELO, Uira Souto; PESSOA, Andre Luiz Santos; NOBREGA, Paulo Ribeiro; KITAJIMA, Joao Paulo; CORREA, Igor; ZATZ, Mayana; KOK, Fernando; SANTOS, SilvanaBackground Intellectual disability (ID) is a highly heterogeneous condition affecting 2% of the population worldwide. In a field study conducted in a highly inbred area of Northeastern Brazil, we investigated a consanguineous family in which seven adults presented syndromic ID. Methods Genome-Wide Human SNP Array 6.0 (Affymetrix) microarray was used to determine regions of homozygosity-by-descent and whole exome sequencing (WES) was performed in one affected individual using Extended Nextera Rapid-Capture Exome and Illumina HiSeq2500. Results We found two regions with an logarithm of the odds (LOD) score of 3.234: a region spanning 4.0 Mb in 19q13.32-q13.33 and a pericentromeric 20 Mb area in chromosome 2 (2p12-q11.2). WES disclosed in the critical region of chromosome 19 a homozygous variant (c.418C> T, p.Arg140Trp) in Mediator complex subunit 25 (MED25), predicted as deleterious by PolyPhen-2, Provean, Mutation Taster and Sorting Intolerant From Tolerant (SIFT). MED25 is a component of the Mediator complex, involved in regulation of transcription of nearly all RNA polymerase II-dependent genes. Deleterious mutations in MED12, MED17 and MED23 have already been associated with ID. Conclusions These findings demonstrate that the combination of field investigation of families in highly inbred regions with modern technologies is an effective way for identifying new genes associated with ID.
- GNBS Mutations Cause an Autosomal-Recessive Multisystem Syndrome with Sinus Bradycardia and Cognitive Disability(2016) LODDER, Elisabeth M.; NITTIS, Pasquelena De; KOOPMAN, Charlotte D.; WISZNIEWSKI, Wojciech; SOUZA, Carolina Fischinger Moura de; LAHROUCHI, Najim; GUEX, Nicolas; NAPOLIONI, Valerio; TESSADORI, Federico; BEEKMAN, Leander; NANNENBERG, Eline A.; BOUALLA, Lamiae; BLOM, Nico A.; GRAAFF, Wim de; KAMERMANS, Maarten; COCCIADIFERRO, Dario; MALERBA, Natascia; MANDRIANI, Barbara; AKDEMIR, Zeynep Hande Coban; FISH, Richard J.; ELDOMERY, Mohammad K.; RATBI, Ilham; WILDE, Arthur A. M.; BOER, Teun de; SIMONDS, William F.; NEERMAN-ARBEZ, Marguerite; SUTTON, V. Reid; KOK, Fernando; LUPSKI, James R.; REYMOND, Alexandre; BEZZINA, Connie R.; BAKKERS, Jeroen; MERLA, GiuseppeGNB5 encodes the G protein beta subunit 5 and is involved in inhibitory G protein signaling. Here, we report mutations in GNB5 that are associated with heart-rate disturbance, eye disease, intellectual disability, gastric problems, hypotonia, and seizures in nine individuals from six families. We observed an association between the nature of the variants and clinical severity; individuals with loss-of-function alleles had more severe symptoms, including substantial developmental delay, speech defects, severe hypotonia, pathological gastro-esophageal re flux, retinal disease, and sinus-node dysfunction, whereas related heterozygotes harboring missense variants presented with a clinically milder phenotype. Zebrafish gnb5 knockouts recapitulated the phenotypic spectrum of affected individuals, including cardiac, neurological, and ophthalmological abnormalities, supporting a direct role of GNB5 in the control of heart rate, hypotonia, and vision.
- Quantification of functional abilities in Rett syndrome: a comparison between stages III and IV(2014) MONTEIRO, Carlos B. M.; SAVELSBERGH, Geert J. P.; SMORENBURG, Ana R. P.; GRACIANI, Zodja; TORRIANI-PASIN, Camila; ABREU, Luiz Carlos de; VALENTI, Vitor E.; KOK, FernandoWe aimed to evaluate the functional abilities of persons with Rett syndrome (RTT) in stages III and IV. The group consisted of 60 females who had been diagnosed with RTT: 38 in stage III, mean age (years) of 9.14, with a standard deviation of 5.84 (minimum 2.2/maximum 26.4); and 22 in stage IV, mean age of 12.45, with a standard deviation of 6.17 (minimum 5.3/maximum 26.9). The evaluation was made using the Pediatric Evaluation of Disability Inventory, which has 197 items in the areas of self-care, mobility, and social function. The results showed that in the area of self-care, stage III and stage IV RTT persons had a level of 24.12 and 18.36 (P=0.002), respectively. In the area of mobility, stage III had 37.22 and stage IV had 14.64 (P<0.001), while in the area of social function, stage III had 17.72 and stage IV had 12.14 (P=0.016). In conclusion, although persons with stage III RTT have better functional abilities when compared with stage IV, the areas of mobility, self-care, and social function are quite affected, which shows a great functional dependency and need for help in basic activities of daily life.
- A endogamia explicaria a elevada prevalência de deficiências em populações do Nordeste brasileiro?(2013) SANTOS, Silvana Cristina dos; MELO, Uira Souto; LOPES, Simone Silva dos Santos; WELLER, Mathias; KOK, FernandoDespite conceptual inaccuracies and methods of measurement, the WHO estimates that about 10% of the world population has some form of disability. In order to investigate the prevalence and etiology of disabilities and to evaluate if they could be associated with inbreeding, a cross-sectional epidemiological study was conducted using the informant method in five communities of the state Rio Grande do Norte in the Brazilian Northeast, in which consanguineous marriages frequencies varied between 9 and 32%. The average prevalence of disabilities in the five sampled communities was 4.53%, obtained by interviews that involved 37.87% of a population of 39,054 inhabitants. On average, 25% of consanguineous and 12% of non-consanguineous couples had one or more children with disabilities. The increased rate of individuals with disabilities in the Brazilian Northeast could be associated with the maintenance of the tradition of consanguineous marriages in these populations and some of these disabilities may be caused by genetic disorders.
- Moyamoya associated with Turner syndrome in a patient with type 2 spinocerebellar ataxia-Occam's razor or Hickam's dictum: a case report(2022) NOBREGA, Paulo Ribeiro; COSTA, Francisco Bruno Santana da; RODRIGUES, Pedro Gustavo Barros; VASCONCELOS, Thais de Maria Frota; SOARES, Danyela Martins Bezerra; ARAUJO, Jessica Silveira; DIAS, Daniel Aguiar; SOBREIRA-NETO, Manoel Alves; PAIVA, Anderson Rodrigues Brandao de; BRAGA-NETO, Pedro; KOK, Fernando; FONTENELE, Eveline Gadelha PereiraBackground Turner syndrome (TS) is a rare condition associated with a completely or partially missing X chromosome that affects 1 in 2500 girls. TS increases the risk of autoimmune diseases, including Graves' disease (GD). Moyamoya disease is a rare cerebral arteriopathy of unknown etiology characterized by progressive bilateral stenosis of the internal carotid artery and its branches. Both TS and GD have been associated with Moyamoya. Type 2 spinocerebellar ataxia (SCA2) is an autosomal dominant cerebellar ataxia caused by a CAG repeat expansion in ATXN2. We present the first case of Moyamoya syndrome in a patient with a previous diagnosis of TS and GD who tested positive for SCA2 and had imaging findings compatible with an overlap of SCA2 and Moyamoya. Case presentation A 43-year-old woman presented with mild gait imbalance for 2 years. Her family history was positive for type 2 spinocerebellar ataxia (SCA2). She had been diagnosed with Turner Syndrome (45,X) and Graves disease three years before. Brain MRI revealed bilateral frontal and parietal cystic encephalomalacia in watershed zones, atrophy of pons, middle cerebellar peduncles and cerebellum. MR angiography showed progressive stenosis of both internal carotid arteries with lenticulostriate collaterals, suggestive of Moya-Moya disease. Molecular analysis confirmed the diagnosis of SCA2. Conclusions With increased availability of tools for genetic diagnosis, physicians need to be aware of the possibility of a single patient presenting two or more rare diseases. This report underscores the modern dilemmas created by increasingly accurate imaging techniques and available and extensive genetic testing.
- A case of mitochondrial DNA depletion syndrome type 11-expanding the genotype and phenotype(2023) ROCHA, Emanuelle Bianchi da Silva; RODRIGUES, Ketteny de Lima; MONTOURO, Laura Alonso Matheus; COELHO, erica Nogueira; KOUYOUMDJIAN, Joao Aris; KOK, Fernando; NOBREGA, Paulo Ribeiro; GRACA, Carla Renata; MORITA, Maria da Penha Ananias; ESTEPHAN, Eduardo de PaulaMitochondrial DNA depletion syndrome type 11 (MTDPS11) is caused by pathogenic variants in MGME1 gene. We report a woman, 40-year-old, who presented slow progressive drop eyelid at 11-year old with, learning difficulty and frequent falls. Phisical examination revealed: mild scoliosis, elbow hyperextensibility, flat feet, chronic progressive external ophthalmoplegia with upper eyelid ptosis, diffuse hypotonia, and weakness of arm abduction and neck flexion. Investigation evidenced mild serum creatine kinase increase and glucose intolerance; second-degree atrioventricular block; mild mixed type respiratory disorder and atrophy and granular appearance of the retinal pigment epithelium. Brain magnetic resonance showed cerebellar atrophy. Muscle biopsy was compatible with mitochondrial myopathy. Genetic panel revealed a homozygous pathogenic variant in the MGME1 gene, consistent with MTDPS11 (c.862C > T; p.Gln288 *). This case of MTDPS11 can contribute to the phenotypic characterization of this ultra-rare mitochondrial disorder, presenting milder respiratory and nutritional involvement than the previously reported cases, with possible additional features.(c) 2023 Elsevier B.V. All rights reserved.
- Motor impairment in a rare form of spastic paraplegia (Spoan syndrome): a 10-year follow-up(2019) GALVAO, Claudia R. C.; CAVALCANTE, Priscilla M. A.; OLINDA, Ricardo; GRACIANI, Zodja; ZATZ, Mayana; KOK, Fernando; SANTOS, Silvana; LANCMAN, SelmaBackground: Spastic paraplegia, optic atrophy and neuropathy (Spoan syndrome) is an autosomal recessive disease with approximately 70 cases recorded in Brazil and Egypt. Methods: This is a prospective longitudinal study performed with 47 patients affected with Spoan syndrome of seven communities of Rio Grande do Norte (Brazil) to investigate changes in motor function based on comparative data obtained from a 10-year follow-up. Results: The mean age of the participants was 47.21 +/- 12.42 years old, and the mean age at loss of ambulation and hand function were 10.78 +/- 5.55 and 33.58 +/- 17.47 years old, respectively. Spearman's correlation analysis between the score on the Modified Barthel Index and the investigated variables evidenced statistical significance for age (p < 0.001) and right- and left-hand grip strength (p = 0.042 and p = 0.021, respectively). Statistical significance was not evidenced for the remainder of the variables, including age at onset of symptoms (p = 0.634), age at loss of ambulation (p = 0.664) and age at loss of hand function (p = 0.118). Conclusions: Our analysis allows asserting that the participants exhibited slight dependence until age 35. The greatest losses occurred from ages 35 to 41, and starting at 50, practically all patients become completely dependent. These findings are relevant for determining the prognosis as well as suitable treatment, rehabilitation and assistive technology for these individuals.
- NERVE CONDUCTION STUDIES IN SPASTIC PARAPLEGIA, OPTIC ATROPHY, AND NEUROPATHY (SPOAN) SYNDROME(2014) AMORIM, Simone; HEISE, Carlos Otto; SANTOS, Silvana; MACEDO-SOUZA, Lucia Ines; ZATZ, Mayana; KOK, FernandoIntroduction: SPOAN (spastic paraplegia, optic atrophy, and neuropathy) syndrome is an autosomal recessive neurodegenerative disorder identified in a large consanguineous Brazilian family. Methods: Twenty-seven patients with SPOAN syndrome (20 women), aged 4-58 years, underwent nerve conduction studies (NCS) of the median, ulnar, tibial, and fibular nerves, and sensory NCS of the median, ulnar, radial, sural, and superficial fibular nerves. Results: Sensory nerve action potentials were absent in the lower limbs and absent in >80% of upper limbs. Motor NCS had reduced amplitudes and borderline velocities in the upper limbs and absent compound muscle action potentials (CMAPs) in the lower limbs. Conclusions: The neuropathy in SPOAN syndrome is a severe, early-onset sensory-motor axonal polyneuropathy. Normal NCS seem to rule-out this condition. Muscle Nerve49: 131-133, 2014
- Clinical and genetic characterization of leukoencephalopathies in adults(2017) LYNCH, David S.; PAIVA, Anderson Rodrigues Brandao de; ZHANG, Wei Jia; BUGIARDINI, Enrico; FREUA, Fernando; LUCATO, Leandro Tavares; MACEDO-SOUZA, Lucia Ines; LAKSHMANAN, Rahul; KINSELLA, Justin A.; MERWICK, Aine; ROSSOR, Alexander M.; BAJAJ, Nin; HERRON, Brian; MCMONAGLE, Paul; MORRISON, Patrick J.; HUGHES, Deborah; PITTMAN, Alan; LAURA, Matilde; REILLY, Mary M.; WARREN, Jason D.; MUMMERY, Catherine J.; SCHOTT, Jonathan M.; ADAMS, Matthew; FOX, Nick C.; MURPHY, Elaine; DAVAGNANAM, Indran; KOK, Fernando; CHATAWAY, Jeremy; HOULDEN, HenryLeukodystrophies and genetic leukoencephalopathies are a rare group of disorders leading to progressive degeneration of cerebral white matter. They are associated with a spectrum of clinical phenotypes dominated by dementia, psychiatric changes, movement disorders and upper motor neuron signs. Mutations in at least 60 genes can lead to leukoencephalopathy with often overlapping clinical and radiological presentations. For these reasons, patients with genetic leukoencephalopathies often endure a long diagnostic odyssey before receiving a definitive diagnosis or may receive no diagnosis at all. In this study, we used focused and whole exome sequencing to evaluate a cohort of undiagnosed adult patients referred to a specialist leukoencephalopathy service. In total, 100 patients were evaluated using focused exome sequencing of 6100 genes. We detected pathogenic or likely pathogenic variants in 26 cases. The most frequently mutated genes were NOTCH3, EIF2B5, AARS2 and CSF1R. We then carried out whole exome sequencing on the remaining negative cases including four family trios, but could not identify any further potentially disease-causing mutations, confirming the equivalence of focused and whole exome sequencing in the diagnosis of genetic leukoencephalopathies. Here we provide an overview of the clinical and genetic features of these disorders in adults.