FERNANDO KOK

(Fonte: Lattes)
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Lattes
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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

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Agora exibindo 1 - 10 de 25
  • article 1 Citação(ões) na Scopus
    Ceroid lipofuscinosis type 5: novel pathogenic variants and unexpected phenotypic findings
    (2023) PAIVA, Anderson Rodrigues Brandao de; PESSOA, Andre Luiz Santos; NOBREGA, Paulo Ribeiro; MORENO, Cristiane Araujo Martins; LYNCH, David S.; TANIGUTI, Lucas Mitsuo; KITAJIMA, Joao Paulo; FREUA, Fernando; DELLA-RIPA, Bruno; CUNHA, Paulina; BARCELOS, Isabella Peixoto de; MACEDO-SOUZA, Lucia Ines; TAKEUCHI, Carlos Augusto; GARCIA, Antonio Milton Silva; NARDES, Flavia; FONTAO, Ramiro; ANTONIUK, Sergio Antonio; TRONCOSO, Monica; SPECOLA, Norma; DURAND, Consuelo; MADEIRO, Bianca de Aguiar Coelho Silva; DORIQUI, Maria Juliana Rodovalho; VERGARA, Diane; HOULDEN, Henry; KOK, Fernando
  • article 16 Citação(ões) na Scopus
    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, Fernando
    We 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.
  • article 2 Citação(ões) na Scopus
    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 Paula
    Mitochondrial 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.
  • article 34 Citação(ões) na Scopus
    Chromosomal microarray analysis in the genetic evaluation of 279 patients with syndromic obesity
    (2018) D'ANGELO, Carla Sustek; VARELA, Monica Castro; CASTRO, Claudia Irene Emilio de; OTTO, Paulo Alberto; PEREZ, Ana Beatriz Alvarez; LOURENCO, Charles Marques; KIM, Chong Ae; BERTOLA, Debora Romeo; KOK, Fernando; GARCIA-ALONSO, Luis; KOIFFMANN, Celia Priszkulnik
    Background: Syndromic obesity is an umbrella term used to describe cases where obesity occurs with additional phenotypes. It often arises as part of a distinct genetic syndrome with Prader-Willi syndrome being a classical example. These rare forms of obesity provide a unique source for identifying obesity-related genetic changes. Chromosomal microarray analysis (CMA) has allowed the characterization of new genetic forms of syndromic obesity, which are due to copy number variants (CNVs); however, CMA in large cohorts requires more study. The aim of this study was to characterize the CNVs detected by CMA in 279 patients with a syndromic obesity phenotype. Results: Pathogenic CNVs were detected in 61 patients (22%) and, among them, 35 had overlapping/recurrent CNVs. Genomic imbalance disorders known to cause syndromic obesity were found in 8.2% of cases, most commonly deletions of 1p36, 2q37 and 17p11.2 (5.4%), and we also detected deletions at 1p21.3, 2p25.3, 6q16, 9q34, 16p11.2 distal and proximal, as well as an unbalanced translocation resulting in duplication of the GNB3 gene responsible for a syndromic for of childhood obesity. Deletions of 9p terminal and 22q11.2 proximal/distal were found in 1% and 3% of cases, respectively. They thus emerge as being new putative obesity-susceptibility loci. We found additional CNVs in our study that overlapped with CNVs previously reported in cases of syndromic obesity, including a new case of 13q34 deletion (CHAMP1), bringing to 7 the number of patients in whom such defects have been described in association with obesity. Our findings implicate many genes previously associated with obesity (e.g. PTBP2, TMEM18, MYT1L, POU3F2, SIM1, SH2B1), and also identified other potentially relevant candidates including TAS1R3, ALOX5AP, and GAS6. Conclusion: Understanding the genetics of obesity has proven difficult, and considerable insight has been obtained from the study of genomic disorders with obesity associated as part of the phenotype. In our study, CNVs known to be causal for syndromic obesity were detected in 8.2% of patients, but we provide evidence for a genetic basis of obesity in as many as 14% of cases. Overall, our results underscore the genetic heterogeneity in syndromic forms of obesity, which imposes a substantial challenge for diagnosis.
  • article 1 Citação(ões) na Scopus
    Aseptic meningitis in Fabry disease due to a novel GLA variant: an expanded phenotype?
    (2023) NOBREGA, Paulo Ribeiro; MORAIS, Joao Lucas Araujo; FERREIRA, Alliane Milliane; MEDEIROS, Alisson Dantas de; DUARTE, Beatrice Araujo; RANGEL, Deborah Moreira; LIMA, Fabricio Oliveira; PAIVA, Anderson Rodrigues Brandao de; PAIM-MARQUES, Luciana; KOK, Fernando; PESSOA, Andre Luiz Santos; BRAGA-NETO, Pedro; CARVALHO, Fernanda Martins Maia
    Background F abry disease (FD) is an X-linked lysosomal storage disorder with accumulation of globotriosylceramide, causing neurologic involvement mainly as acroparesthesias and cerebrovascular disease. Aseptic meningitis has been reported in 11 patients with FD, but no prior study has correlated alpha-galactosidase (GLA) specific variants with meningitis. We present in this manuscript a family in which a novel GLA pathogenic variant was associated with aseptic meningitis in 2 of 5 family members. Methods This study began with identifying the proband, then screening family members for FD symptoms and evaluating symptomatic individuals for genetic and biochemical status. All patients underwent magnetic resonance imaging, and those with headache underwent cerebrospinal fluid (CSF) analysis. Results Five patients (3 females) from a single family were included in this study. Mean age at diagnosis was 20.6 years. Two patients (40%) had aseptic meningitis; one of them also had cerebrovascular events. C-reactive protein and erythrocyte sedimentation rate were elevated during aseptic meningitis episodes. Both patients responded to intravenous methylprednisolone with resolution of fever, headache, and vomiting. One of them recurred and needed chronic immunosuppression with azathioprine. Conclusion We described aseptic meningitis in a family with a novel GLA variant. Meningitis might be a common phenomenon in FD and not a particularity of this variant. Understanding the mechanisms underlying meningitis and its association with cerebrovascular events may lead to a new paradigm of treatment for stroke in these patients. Further prospective studies with CSF collection in patients with FD and recurrent headache could help to elucidate this question.
  • article 1 Citação(ões) na Scopus
    Subacute Partially Reversible Leukoencephalopathy Expands the Aicardi-Goutieres Syndrome Phenotype
    (2023) BARCELOS, Isabella Peixoto de; BUENO, Clarissa; GODOY, Luis Filipe S.; PESSOA, Andre; COSTA, Larissa A.; MONTI, Fernanda C.; SOUZA-CABRAL, Katiane; LISTIK, Clarice; CASTRO, Diego; DELLA-RIPA, Bruno; FREUA, Fernando; PIRES, Lais C.; KRUGER, Lia T.; GHERPELLI, Jose Luiz D.; PIAZZON, Flavia B.; MONTEIRO, Fabiola P.; LUCATO, Leandro T.; KOK, Fernando
    Objective: To report a series of atypical presentations of Aicardi-Goutieres syndrome. Methods: Clinical, neuroimaging, and genetic data. Results: We report a series of six unrelated patients (five males) with a subacute loss of developmental milestones, pyramidal signs, and regression of communication abilities, with onset at ages ranging from 7 to 20 months, reaching a nadir after 4 to 24 weeks. A remarkable improvement of lost abilities occurred in the follow-up, and they remained with residual spasticity and dysarthria but preserved cognitive function. Immunization or febrile illness occurred before disease onset in all patients. CSF was normal in two patients, and in four, borderline or mild lymphocytosis was present. A brain CT scan disclosed a subtle basal ganglia calcification in one of six patients. Brain MRI showed asymmetric signal abnormalities of white matter with centrum semi-ovale involvement in five patients and a diffuse white matter abnormality with contrast enhancement in one. Four patients were diagnosed and treated for acute demyelinating encephalomyelitis (ADEM). Brain imaging was markedly improved with one year or more of follow-up (average of 7 years), but patients remained with residual spasticity and dysarthria without cognitive impairment. Demyelination relapse occurred in a single patient four years after the first event. Whole-exome sequencing (WES) was performed in all patients: four of them disclosed biallelic pathogenic variants in RNASEH2B (three homozygous p.Ala177Thr and one compound heterozygous p.Ala177Thr/p.Gln58*) and in two of them the same homozygous deleterious variants in RNASEH2A (p.Ala249Val). Conclusions: This report expands the phenotype of AGS to include subacute developmental regression with partial clinical and neuroimaging improvement. Those clinical features might be misdiagnosed as ADEM.
  • article 0 Citação(ões) na Scopus
    Stroke in vascular Ehlers-Danlos syndrome
    (2023) MARTINS, Rebecca Ranzani; PAIVA, Mauricio Leonardo da Silva; TEIXEIRA, Weverton Carlos da Silva; KAWAHIRA, Rachel Sayuri Honjo; FREUA, Fernando; CASTRO, Matheus Augusto Araujo; KIM, Chong Ae; KOK, Fernando
  • article 1 Citação(ões) na Scopus
    The fructose-1,6-bisphosphatase deficiency and the p.(Lys204ArgfsTer72) variant
    (2021) PINHEIRO, Franciele Cabral; LIGABUE-BRAUN, Rodrigo; SIQUEIRA, Ana Cecilia Menezes de; MATUELLA, Camila; SOUZA, Carolina Fischinger Moura de; MONTEIRO, Fabiola Paoli; KOK, Fernando; SCHWARTZ, Ida Vanessa Doederlein; SPERB-LUDWIG, Fernanda
    Fructose-1,6-bisphosphatase (FBPase) deficiency is a rare inborn error of fructose metabolism caused by pathogenic variants in the FBP1 gene. As gluconeogenesis is affected, catabolic episodes can induce ketotic hypoglycemia in patients. FBP1 analysis is the most commonly used approach for the diagnosis of this disorder. Herein, a Brazilian patient is reported. The proband, a girl born to a consanguineous couple, presented with severe hypoglycemia crisis in the neonatal period. At the age 17 months, presented a new crisis accompanied by metabolic acidosis associated with a feverish episode. Genetic analysis was performed by next-generation sequencing (NGS), identifying the NM_000507.3:c.611_614del variant in homozygosis in the FBP1 gene. In silico analysis and 3D modeling were performed, suggesting that this variant is associated with a loss of sites for substrate and Mg2+ binding and for posttranslational modifications of FBPase. The c.611_614del variant is located in a repetitive region of the FBP1 gene that appears to be a hotspot for mutational events. This frameshift creates a premature termination codon in the last coding exon which escapes the nonsense-mediated decay mechanism, according to in silico analysis. This variant results in an intrinsically disordered protein with loss of substrate recognition and post-translational modification sites.
  • article 5 Citação(ões) na Scopus
    The segregation of different submicroscopic imbalances underlying the clinical variability associated with a familial karyotypically balanced translocation
    (2015) FONSECA, Ana Carolina S.; BONALDI, Adriano; FONSECA, Simone A. S.; OTTO, Paulo A.; KOK, Fernando; BAK, Mads; TOMMERUP, Niels; VIANNA-MORGANTE, Angela M.
    Background: About 7 % of karyotypically balanced chromosomal rearrangements (BCRs) are associated with congenital anomalies due to gene or regulatory element disruption, and cryptic imbalances on rearranged chromosomes. Rare familial BCRs segregating with clinical features are a powerful source for the identifying of causative genes due to the presence of several affected carriers. Case presentation: We report on a karyotypically balanced translocation t(2;22)(p13;q12.2) associated with variable learning disabilities, and craniofacial and hand dysmorphisms, detected in six individuals in a three-generation family. Combined a-CGH, FISH and mate-pair sequencing revealed a ten-break complex rearrangement, also involving chromosome 5. As the consequence of the segregation of the derivative chromosomes der(2), der(5) and der(22), different imbalances were present in affected and clinically normal family members, thus contributing to the clinical variability. A 6.64 Mb duplication of a 5q23.2-23.3 segment was the imbalance common to all affected individuals. Although LMNB1, implicated in adult-onset autosomal dominant leukodystrophy (ADLD) when overexpressed, was among the 18 duplicated genes, none of the adult carriers manifested ADLD, and LMNB1 overexpression was not detected in the two tested individuals, after qRT-PCR. The ectopic location of the extra copy of the LMBN1 gene on chromosome 22 might have negatively impacted its expression. In addition, two individuals presenting with more severe learning disabilities carried a 1.42 Mb 2p14 microdeletion, with three genes (CEP68, RAB1A and ACTR2), which are candidates for the intellectual impairment observed in the previously described 2p14p15 microdeletion syndrome, mapping to the minimal overlapping deleted segment. A 5p15.1 deletion, encompassing 1.47 Mb, also detected in the family, did not segregate with the clinical phenotype. Conclusion: The disclosing of the complexity of an apparently simple two-break familial rearrangement illustrates the importance of reconstructing the precise structure of derivative chromosomes for establishing genotype-phenotype correlations.
  • article
    Does MRS Lactate Peak Correlate with Lactate in the CSF and Blood?
    (2015) SHIBAO, Simone; OTADUY, Maria C. G.; KOK, Fernando; LEITE, Claudia C.
    Purpose Cerebrospinal fluid (CSF) or brain parenchyma lactate detection is important for the diagnosis of some diseases with aerobic cellular metabolism compromise. Our purpose is to correlate intraventricular magnetic resonance spectroscopy (MRS) lactate detection and quantification to CSF and blood lactate concentration. Methods Twenty-one patients (13 females; mean age 5 years) suspected of having mitochondrial disorders underwent proton MRS with point-resolved spectroscopy (TE = 144 ms). The volume of interest was positioned in the lateral ventricles, and LCModel was used for the MRS lactate peak detection and quantification. CSF and venous blood samples were obtained for lactate quantification immediately after MRS. Comparisons between MRS, CSF, and blood lactate detection and quantification were performed. p < 0.05 was considered significant. Results In our series, CSF lactate levels were high in 11 patients (52%) and blood serum lactate levels were high in 3 patients (14%). MRS was able to detect a lactate peak in all patients. A positive correlation between MRS lactate quantification and CSF lactate was observed (Pearson correlation coefficient = 0.750; p < 0.0001). Blood lactate did not correlate with lactate levels in the lateral ventricle measured by MRS or direct determinations of CSF lactate concentration. When noting the lactate quantification obtained by MRS, only 8 patients (as opposed to 14) presented higher values than the established normality threshold of 1.7 mmol/L. Considering CSF puncture concentration as the gold standard, we obtained 64% of sensitivity and 90% of specificity for MRS quantification. Conclusion If MRS shows increased lactate levels in the ventricles, CSF puncture is not needed for lactate increase confirmation.