Caracterização clínica e molecular das miopatias hereditárias no Brasil

As miopatias hereditárias (HM) são um grupo de doenças com grande heterogeneidade clínica e genética e o tempo decorrido desde o início dos sintomas até o correto diagnóstico pode ser muito longo. Diversos exames complementares de alto custo e invasivos são realizados na tentativa de um diagnóstico definitivo implicando num elevado custo pessoal, familiar e social. O recente uso das tecnologias de sequenciamento por nova geração (NGS) tem revolucionado o diagnóstico molecular dessas condições. Entretanto, são escassos os estudos que avaliam o rendimento diagnóstico dessa estratégia e faltam dados epidemiológicos sobre essas condições no Brasil e na América Latina. O objetivo da presente tese foi avaliar o rendimento de um painel de genes de NGS para o diagnóstico das HM no sul do Brasil assim como avaliar as características clínicas, genéticas e eventuais modificadores de fenótipo no subgrupo das distrofias musculares de cinturas (LGMD) no Brasil. Para isso, dois estudos foram realizados. No primeiro estudo, uma coorte histórica multicêntrica de casos índices consecutivos e seus familiares com diagnóstico genético ou patológico de LGMD recessiva (LGMD2) foi avaliada. Curvas de sobrevida para incapacidade física nas LGMD2A, LGMD2B e sarcoglicanopatias foram construídas e avaliaram-se as progressões clínicas de acordo com o sexo e genótipo. No segundo estudo, um estudo transversal de casos índices consecutivos com suspeita clínica de HM num centro único especializado em doenças neuromusculares no sul do Brasil, objetivou-se avaliar o rendimento diagnóstico de um painel NGS personalizado compreendendo 39 genes como teste de primeira linha para o diagnóstico de HM além de caracterizar os achados clínicos e moleculares de famílias com HM nesta população. O primeiro estudo avaliou 370 pacientes (305 famílias) com LGMD2, os subtipos mais frequentes foram LGMD2A e LGMD2B, cada um representando cerca de 30% das famílias. As sarcoglicanopatias foram o subtipo de início na infância mais frequente, representando 21% das famílias. Cinco por cento das famílias tinham LGMD2G, um subtipo ultrarraro em todo o mundo. Mulheres com LGMD2B tiveram progressão menos grave para deficiência que homens e pacientes com LGMD2A com variantes truncadas tiveram início da doença mais precoce e progressão mais grave para deficiência do que pacientes sem variantes truncadas. No segundo estudo 51 casos índices consecutivos foram avaliados e o rendimento diagnóstico geral do painel NGS foi de 52,9%, aumentando para 60,8% ao incluir casos de HM com variantes candidatas. O painel NGS resolveu o diagnóstico de 12/25 (48%) probandos LGMD, de 7/14 (50%) com doenças musculares congênitas (CMD) e de 7/10 (70%) com distrofia muscular com contraturas articulares proeminentes (MDJC). Os diagnósticos mais frequentes para LGMD foram LGMD2A e LGMD2B; para CMD, distúrbios relacionados ao RYR1; e para 7 MDJC, distrofia muscular de Emery Dreifuss tipo 1 e distúrbios relacionados com COL6A1. Dezesseis novas variantes foram relatadas. Através da presente tese foi possível definir dados epidemiológicos importantes de LGMD no Brasil, sendo os subtipos LGMD2A e LGMD2B os mais frequentes, diferentemente do que se pensava anteriormente, seguido pelas sarcoglicanopatias que foram os subtipos de início na infância mais frequentes. Conseguimos avaliar modificadores de fenótipos como a gravidade da mutação para LGMD2A e o efeito do sexo para LGMD2B. Essa é a maior série mundial de LGMD2 com dados clínicos e moleculares detalhados já descrita. Além disso o painel NGS personalizado quando aplicado na investigação inicial de HM resulta em um alto rendimento diagnóstico, reduzindo a odisseia diagnóstica do paciente e fornecendo informações importantes para aconselhamento genético e para participação em ensaios clínicos futuros.Hereditary myopathies (HM) are a group of diseases with great clinical and genetic heterogeneity, and the time from the onset of symptoms to the correct diagnosis can be very long. Several high-cost and invasive complementary exams are performed to reach a definitive diagnosis, implying a high personal, family and social cost. The recent use of next generation sequencing (NGS) technologies has revolutionized the molecular diagnosis of these conditions. However, there are few studies that assess the diagnostic yield of this strategy and there is a lack of epidemiological data on these conditions in Brazil and Latin America. The aim of this thesis was to evaluate the performance of a panel of NGS genes for the diagnosis of MH in southern Brazil, as well as to evaluate the clinical, genetic and possible phenotype modifiers in the limb girdle muscular dystrophy (LGMD) subgroup in Brazil. For this, two studies were carried out. In the first study, a multicentric historical cohort of consecutive index cases and their families with genetic or pathological diagnosis of recessive LGMD (LGMD2) was evaluated. Survival curves for physical disability in LGMD2A, LGMD2B and sarcoglycanopathies were constructed and clinical progressions were evaluated according to sex and genotype. In the second study, a cross-sectional study of consecutive index cases with clinical suspicion of HM in a single center specializing in neuromuscular diseases in southern Brazil, aimed to evaluate the diagnostic yield of a personalized NGS panel comprising 39 genes as a first-tier test for the diagnosis of HM in addition to characterizing the clinical and molecular findings of families with HM in this population. The first study evaluated 370 patients (305 families) with LGMD2, the most frequent subtypes were LGMD2A and LGMD2B, each representing about 30% of families. Sarcoglycanopathies were the most frequent childhood onset subtype, representing 21% of families. Five percent of families had LGMD2G, an ultra-rare subtype worldwide. Women with LGMD2B had less severe progression to disability than men, and LGMD2A patients with truncated variants had earlier disease onset and more severe progression to disability than patients without truncated variants. In the second study 51 consecutive index cases were evaluated and the overall diagnostic yield of the NGS panel was 52.9%, increasing to 60.8% when including cases of HM with candidate variants. The NGS panel resolved the diagnosis of 12/25 (48%) LGMD probands, 7/14 (50%) with congenital muscle diseases (CMD) and 7/10 (70%) with muscular dystrophy with prominent joint contractures (MDJC). The most frequent diagnoses for LGMD were LGMD2A and LGMD2B; for CMD, RYR1 related disorders; and for MDJC, Emery Dreifuss muscular dystrophy type 1 and COL6A1 related disorders. Sixteen new variants were reported. Through this thesis, it was possible to define important epidemiological data of LGMD in Brazil, with the subtypes 9 LGMD2A and LGMD2B being the most frequent, differently from what was previously thought, followed by the sarcoglycanopathies that were the most frequent subtypes of childhood onset. We were able to assess phenotype modifiers such as mutation severity for LGMD2A and sex effect for LGMD2B. This is the world's largest LGMD2 series with detailed clinical and molecular data ever described. Furthermore, the customized NGS panel when applied in the initial investigation of HM results in a high diagnostic yield, reducing the patient's diagnostic odyssey and providing important information for genetic counseling and for participation in future clinical trials

Desempenho cognitivo em pacientes com Miastenia Gravis : uma associação com o uso de glucocorticoides e depressão

We investigated the cognitive performance of patients with Myasthenia Gravis (MG) through a cross-sectional study. A battery of cognitive assessments and self-report questionnaires regarding quality of life (QoL), sleep, and depression were applied. The sample consisted of 39 patients diagnosed with MG. The scores showed a predominance of cognitive impairment in the Montreal Cognitive Assessment screening test (MoCA) (66.7%) and in the immediate (59.0%) and recent memory (56.4%) tests. However, after the Poisson regression analysis with robust variance, it was found that patients diagnosed with depression had a prevalence ratio (PR) of 1,887 (CI 1,166‒3,054) for lower MoCA scores, PR=9,533 (CI 1,600‒56,788) for poorer phonemic verbal fluency scores, and PR=12,426 (CI 2,177‒70,931) for the Semantic Verbal Fluency test. Moreover, concerning a decline in short-term memory retention, patients using glucocorticosteroids (GC) and with Beck Depression Inventory scores indicating depression showed PR=11,227 (CI 1,736‒72,604) and PR=0.35 (CI 0.13‒0.904), respectively. No correlation was found between the QoL questionnaire and performance in cognitive tests. We found worse performance in tasks of memory and executive functions in MG patients. These are not associated with the length and severity of the disease. However, a significant prevalence ratio was found for poorer memory performance in patients diagnosed with depression and in those using GC.Investigamos o desempenho cognitivo de pacientes com miastenia gravis (MG) por meio de um estudo transversal. Aplicou-se uma bateria de avaliações cognitivas e questionários de autopercepção sobre qualidade de vida (QV), sono e depressão. A amostra foi composta por 39 pacientes com diagnóstico de MG. Os escores mostraram predominância de comprometimento cognitivo no teste de rastreio Montreal Cognitive Assessment (MoCA) (66,7%) e nas tarefas de memória imediata (59,0%) e recente (56,4%). Entretanto, após a análise de regressão de Poisson com variância robusta, verificou-se que os pacientes diagnosticados com depressão apresentaram uma razão de prevalência (RP)=1.887 (IC 1.166‒3.054) para escores mais baixos no MoCA, RP=9.533 (IC 1.600‒56.788) nos testes de fluência verbal fonêmica e RP=12.426 (IC 2.177‒70.931) no teste de fluência verbal semântica. Além disso, uma associação entre pior desempenho nas tarefas de memória de retenção de curto prazo nos pacientes em uso de glucocorticoides (GC) e com os escores do Beck Depression Inventory indicando depressão, com RP=11.227 (IC 1.736‒72.604) e RP=0.35 (IC 0.13‒0.904), respectivamente. Não foi encontrada correlação entre o questionário de QV e o desempenho em testes cognitivos. Sendo assim, conclui-se que foi observado pior desempenho em tarefas de memória e funções executivas em pacientes com MG. Estes não estão associados ao tempo e à gravidade da doença. No entanto, uma taxa de prevalência significativa foi encontrada para pior desempenho da memória em pacientes diagnosticados com depressão e naqueles em uso de glucocorticoides

Oppositionality and sympathetic skin response in adolescents : specific associations with the headstrong/hurtful dimension

Oppositionality encompasses distinct dimensions, and few studies have investigated the validity of such distinctions from a pathophysiological perspective. Our aim was to investigate the association between sympathetic skin responses (SSR) and distinct oppositional dimensions in a community sample of adolescents. Forty adolescents aged 13.84 ± 1.46 years participated in this study. Oppositionality was measured by externalizing behavior and bullying scores (dependent variables), while SSR was recorded by electrical changes at the skin level (independent variables). Results showed that increased SSRs were associated with oppositionality; however, these associations were specific to the headstrong/hurtful dimension. Further exploratory analyses demonstrated that increased SSRs were associated with several types of headstrong/hurtful behaviors and underscore the importance of the first aversive stimuli to differentiate groups with low and high headstrong/hurtful behaviors. There were no differences between groups regarding time until habituation. This study provides insights about how dysfunctions in autonomic balance may contribute to the emergence of oppositional behavior among adolescents

Evoked potentials as biomarkers of hereditary spastic paraplegias : a case-control study

Introduction: The Hereditary Spastic Paraplegias (HSP) are a group of genetic diseases that lead to slow deterioration of locomotion. Clinical scales seem to have low sensitivity in detecting disease progression, making the search for additional biomarkers a paramount task. This study aims to evaluate the role of evoked potentials (EPs) as disease biomarkers of HSPs. Methods: A single center cross-sectional case-control study was performed, in which 18 individuals with genetic diagnosis of HSP and 21 healthy controls were evaluated. Motor evoked potentials (MEP) obtained with transcranial magnetic stimulation and somatosensory evoked potentials (SSEP) were performed in lower (LL) and upper limbs (UL). Results: Central motor conduction time in lower limbs (CMCT-LL) was prolonged in HSP subjects, with marked reductions in MEP-LL amplitudes when compared to the control group (p<0.001 for both comparisons). CMCT-UL was 3.59ms (95% CI: 0.73 to 6.46; p = 0.015) prolonged and MEP-UL amplitudes were reduced (p = 0.008) in the HSP group. SSEP-LL latencies were prolonged in HSP subjects when compared to controls (p<0.001), with no statistically significant differences for upper limbs (p = 0.147). SSEP-UL and SSEP-LL latencies presented moderate to strong correlations with age at onset (Rho = 0.613, p = 0.012) and disease duration (Rho = 0.835, p<0.001), respectively. Similar results were obtained for the SPG4 subgroups of patients. Conclusion: Motor and somatosensory evoked potentials can adequately differentiate HSP individuals from controls. MEP were severely affected in HSP subjects and SSEP-LL latencies were prolonged, with longer latencies being related to more severe disease. Future longitudinal studies should address if SSEP is a sensitive disease progression biomarker for HSP