The p21-activated kinases in neural cytoskeletal remodeling and related neurological disorders

The serine/threonine p21-activated kinases (PAKs), as main effectors of the Rho GTPases Cdc42 and Rac, represent a group of important molecular switches linking the complex cytoskeletal networks to broad neural activity. PAKs show wide expression in the brain, but they differ in specific cell types, brain regions, and developmental stages. PAKs play an essential and differential role in controlling neural cytoskeletal remodeling and are related to the development and fate of neurons as well as the structural and functional plasticity of dendritic spines. PAK-mediated actin signaling and interacting functional networks represent a common pathway frequently affected in multiple neurodevelopmental and neurodegenerative disorders. Considering specific small-molecule agonists and inhibitors for PAKs have been developed in cancer treatment, comprehensive knowledge about the role of PAKs in neural cytoskeletal remodeling will promote our understanding of the complex mechanisms underlying neurological diseases, which may also represent potential therapeutic targets of these diseases.

A journey through the history of Neurogenetics / Uma jornada pela história da Neurogenética

ABSTRACT Since the late 19th century, when several inherited neurological disorders were described, the close relationship between Neurology and heredity were well documented by several authors in a pre-genetic era. The term Neurogenetics came to integrate two large sciences and clinical practices: Neurology and Genetics. Neurogenetics is the emerging field that studies the correlation between genetic code and the development and function of the nervous system, including behavioral traits, personality and neurological diseases. In this historical note, a timeline shows the main events and contributors since the first reports of neurogenetic diseases until the current days. In the recent years, neurologists are experiencing much broader use of new genetic diagnosis techniques in clinical practice. Thus, new challenges are arising in diagnostic approach, ethical considerations, and therapeutic options. This article aims to summarize the main historical hallmarks of Neurogenetics, from the pre-DNA era to the present, and the future directions of the field.

RESUMO Desde o final do século XIX, quando diversas doenças neurológicas hereditárias foram descritas, a associação entre neurologia e hereditariedade foi bem documentada por vários autores na era pré-genética. O termo Neurogenética integra dois campos da ciência e da prática clínica: Neurologia e Genética. A Neurogenética é o campo que estuda a correlação entre o código genético e o desenvolvimento e a função do sistema nervoso, incluindo comportamento, personalidade e doenças neurológicas. Nesta nota histórica, a linha do tempo mostra os principais eventos e pesquisadores desde os primeiros relatos de doenças neurogenéticas até os dias atuais. Recentemente, neurologistas estão se deparando com maior uso de técnicas diagnósticas genéticas na prática clínica; portanto, novos desafios surgem na abordagem diagnóstica, nas considerações éticas e na terapêutica. Este artigo almeja resumir os principais marcos históricos da Neurogenética, desde a era pré-DNA até o presente, e os caminhos futuros desse campo de conhecimento.

Role of non-coding RNAs in non-aging-related neurological disorders

Protein coding sequences represent only 2% of the human genome. Recent advances have demonstrated that a significant portion of the genome is actively transcribed as non-coding RNA molecules. These non-coding RNAs are emerging as key players in the regulation of biological processes, and act as "fine-tuners" of gene expression. Neurological disorders are caused by a wide range of genetic mutations, epigenetic and environmental factors, and the exact pathophysiology of many of these conditions is still unknown. It is currently recognized that dysregulations in the expression of non-coding RNAs are present in many neurological disorders and may be relevant in the mechanisms leading to disease. In addition, circulating non-coding RNAs are emerging as potential biomarkers with great potential impact in clinical practice. In this review, we discuss mainly the role of microRNAs and long non-coding RNAs in several neurological disorders, such as epilepsy, Huntington disease, fragile X-associated ataxia, spinocerebellar ataxias, amyotrophic lateral sclerosis (ALS), and pain. In addition, we give information about the conditions where microRNAs have demonstrated to be potential biomarkers such as in epilepsy, pain, and ALS.

Del fenotipo neuropsiquiátrico al cuidado clínico del síndrome de Angelman: descripción de siete casos / Neuropsychiatrie phenotype of Angelman syndrome and clinical care: report of seven cases

El síndrome de Angelman es un trastorno neurogenético debido a la falta o reducción en la expresión del gen UBE3A en el cromosoma 15, el cual codifica la proteína ubiquitina ligasa E3A, que tiene un papel integral en el desarrollo sinóptico y la plasticidad neuronal. Se manifiesta por retraso en el neurodesarrollo o discapacidad intelectual, comportamiento característico y epilepsia. Se describen las características clínicas de siete pacientes con deleción del cromosoma 15q11-13 y su manejo integral. Por la expectativa de vida, es importante conocer y manejar las comorbilidades de forma interdisciplinaria para lograr mejorar la calidad de vida de los afectados. Se realiza una revisión de la literatura sobre la aproximación integral al diagnóstico y cuidado clínico a largo plazo de los pacientes con síndrome de Angelman.

Angelman syndrome is a neurogenetic disorder caused by a lack or reduction of expression of UBE3A located within chromosome 15, which codes for ubiquitin protein ligase E3A, which has a key role in synaptic development and neural plasticity. Its main features are developmental delay/intellectual disability, lack of speech, a characteristic behavioural profile, and epilepsy. We describe clinical features and management of seven cases with 15q11-13 deletion. Due to their life expectancy, knowing and managing its comorbidities is crucial to improve their quality of life. We review the diagnosis and long-term clinical care of patients with Angelman syndrome.

Fenotipos neurológicos en pacientes estudiados con citogenética en el Hospital de Puerto Montt / Neurological phenotypes in cytogenic study from Puerto Montt Hospital patients

El examen citogenético, es una herramienta importante para confirmar el diagnóstico, manejo y consejo genético. El objetivo es analizar las características del fenotipo neuroconductual, protocolizar y orientar en la eficaz solicitud del estudio citogenético. Se revisaron las fichas clínicas de los pacientes controlados del policlínico de Neuropediatría del Hospital de Puerto Montt, con cariograma anormal entre los años 2007 y 2012. De 248 pacientes, 12% se identificó una alteración; 58% aberraciones estructurales, 20% aneuploidías, y 20% alteraciones genético - moleculares. Los elementos clínicos que se encontraron fueron microcefalia 48%, retraso mental 67%, historia familiar 67%, hipotonía 70%, convulsiones 41%, alteraciones del SNC 37%.

Cytogenetic examination is an important tool for confirming diagnosis, case management and genetic counseling. The aim is to analyze the characteristics of neurobehavioral phenotypes, formalize and guide the effective application of cytogenetics. The medical records of patients with abnormal karyotype seen between 2007 and 2012 at the Hospital of Puerto Montt's neuropaediatric outpatient clinic were reviewed. Of 248 patients, in 12% an alteration was identified; 58% structural aberrations, 20% aneuploidy, and 20% genetic-molecular alterations. The clinical elements found were 48% microcephaly, 67% mental retardation, 67% family history, 70% hypotonia, 41% seizures, 37% CNS disorders.

Nasolacrimal Duct Mucocele: Case Report and Literature Review

Introduction Mucoceles are benign expansive cystic formations, composed of a mucus-secreting epithelium (respiratory or pseudostratified epithelium). Nasolacrimal mucocele occurs in a small proportion of children with nasolacrimal duct obstruction and is characterized by a cystic mass in the medial canthus with dilation of the nasolacrimal duct; although dacryocystoceles are rare in adults, they have been reported in patients with trachoma. Objective Discuss clinical aspects, diagnosis, and therapeutic management of mucocele of nasolacrimal duct based on literature review. Resumed Report The authors report a case of bilateral congenital nasolacrimal duct cysts in a 30-year-old man, identified as a tumor in the topography of both lacrimal sacs since birth without associated symptoms. The patient underwent successive surgical treatments, leading to recurrence of the tumor at the right side and recurrent local infections. Conclusion Endoscopic dacryocystorhinostomy has been increasingly used with good results and success rates similar to the external access. .

Application of Array-Based Comparative Genomic Hybridization to Pediatric Neurologic Diseases

PURPOSE: Array comparative genomic hybridization (array-CGH) is a technique used to analyze quantitative increase or decrease of chromosomes by competitive DNA hybridization of patients and controls. This study aimed to evaluate the benefits and yield of array-CGH in comparison with conventional karyotyping in pediatric neurology patients. MATERIALS AND METHODS: We included 87 patients from the pediatric neurology clinic with at least one of the following features: developmental delay, mental retardation, dysmorphic face, or epilepsy. DNA extracted from patients and controls was hybridized on the Roche NimbleGen 135K oligonucleotide array and compared with G-band karyotyping. The results were analyzed with findings reported in recent publications and internet databases. RESULTS: Chromosome imbalances, including 9 cases detected also by G-band karyotyping, were found in 28 patients (32.2%), and at least 19 of them seemed to be causally related to the abnormal phenotypes. Regarding each clinical symptom, 26.2% of 42 developmental delay patients, 44.4% of 18 mental retardation patients, 42.9% of 28 dysmorphic face patients, and 34.6% of 26 epilepsy patients showed abnormal array results. CONCLUSION: Although there were relatively small number of tests in patients with pediatric neurologic disease, this study demonstrated that array-CGH is a very useful tool for clinical diagnosis of unknown genome abnormalities performed in pediatric neurology clinics.

Epigenética y epigenoma: Un paso más allá en la etiología y potencial tratamiento de las enfermedades neurológicas / Epigenetics and epigenome: A step forward in the etiology and potential treatment of neurological diseases

Los mecanismos de regulación epigenética poseen una función muy importante en el desarrollo y en la función de todos los sistemas del organismo. El fracaso en el normal mantenimiento de esta regulación y desarrollo, debido a factores ambientales, podría contribuir al desarrollo de múltiples enfermedades en pacientes predispuestos genéticamente. Si bien la fisiopatología de gran parte de las enfermedades es desconocida en sus mecanismos moleculares más finos, existen evidencias de que la mayoría de los mecanismos fisiopatológicos convergerían a una interacción entre los genes y el ambiente. La epigenética nos permitiría estudiar la interacción mencionada en los niveles moleculares de regulación de la expresión o supresión de un gen y su relación con diversas enfermedades. Particularmente las enfermedades neurológicas, por su complejidad, la gran cantidad de genes involucrados y la influencia ambiental, son un ámbito más que apropiado para investigar potenciales mecanismos epigenéticos en su fisiopatogenia y desarrollo. La presente revisión tiene como objetivo describir en detalle los mecanismos de regulación epigenética y los hallazgos conocidos que provocarían la disfunción de estos mecanismos como posibles desencadenantes de diferentes enfermedades neurológicas.

The mechanisms of epigenetic regulation play an important role in the development and function of body systems. Failure in the maintenance of this regulation as well as environmental factors could contribute to the development of multiple disease s in genetically predisposed patients. Although the molecular mechanisms responsible for the etiology of most diseases are unknown, there is evidence of both genetic and environmental factors that could influence this development. Recent findings involve epigenetic mechanisms in the origin of various diseases. This review aims to describe in detail the mechanisms of epigenetic regulation and the known findings involving the dysfunction of these mechanisms as a possible cause of various diseases.

Aprendizado e memória / Learning and memory

A memória é dividida de duas grandes formas: explícita e implícita. O hipocampo é necessário para a formação das memórias explícitas, ao passo que várias outras regiões do cérebro, incluindo o estriado, a amígdala e o nucleus accumbens, estão envolvidos na formação das memórias implícitas. A formação de todas as memórias requer alterações morfológicas nas sinapses: novas sinapses devem ser formadas ou antigas precisam ser fortalecidas. Considera-se que essas alterações reflitam a base celular subjacente das memórias persistentes. Consideráveis avanços têm ocorrido na última década em relação a nossa compreensão sobre as bases moleculares da formação dessas memórias. Um regulador-chave da plasticidade sináptica é uma via de sinalização que inclui a proteína-quinase ativada por mitógenos (MAP). Como essa via é necessária para a memória e o aprendizado normais, não é surpreendente que as mutações nos membros dessa via levem a prejuízos no aprendizado. A neurofibromatose, a síndrome de Coffin-Lowry e a de Rubinstein-Taybi são três exemplos de transtornos de desenvolvimento que apresentam mutações em componentes-chave na via de sinalização da proteína-quinase MAP.

Molecular biology of neuronal voltage-gated calcium channels

No abstract available.

Mitocôndrias e doenças neurologicas / Mitochondrical and neurological diseases

Os autores revêem a literatura atual acerca das enfermidades neurológicas relacionadas aos distúrbios das mitocôndrias. Inicialmente, recordam-se os conceitos fisiológicos desta organela, caracterizando-se a seguir, de forma genérica, sua disfunçåo sob o ponto de vista clínico e laboratorial. Descrevem-se especificamente as principais neuromitocondriopatias primárias (oftalmoplegia extrínseca progressiva, síndrome de KearnsSayre, MERRF, MELAS, NARP, atrofia óptica de Leber, MiMyCa, MINGIE/POLIP, síndrome de Pearson, síndrome de Leigh, doença de Alpers) e secundárias (doença de Menkes, miopatia da AZT, doença de Parkinson). Por fim, säo tecidas consideraçöes acerca das principais abordagens terapêuticas nestas afecçöes

Molecular genetics in neurology

Genetically determined diseases with neurological manifestations constitute a big public health problem in many communities including Saudi Arabia. As a result of advances in molecular genetics, the bases of several neurological diseases have now been deciphered. A whole series of genes of neurologic interest have been cloned and sequenced. The analysis of human DNA using recombinant technology is fast becoming an integral part of the diagnosis of number of neurological disorders. It is expected that new methods of mapping the human genome will provide us with a valuable approach in elucidating molecular pathology of these conditions and preventing them. This review presents recent advances in molecular neurogenetics and molecular techniques used for gene analysis as a prelude to possible gene therapy