Peripheral neuropathy associated with agenesis of the corpus callosum (ACCPN or HMSN/ACC) is a severe polyneuropathy affecting both the peripheral nervous system and the central nervous system. It is transmitted as an autosomal recessive trait and is particularly frequent in the French Canadian population of Quebec (Canada). The disease was linked to chromosome 15 in 1996 by Dr. Rouleau's team. / We genotyped polymorphic markers in the ACCPN candidate region on chromosome 15 in over 67 patients and 200 control individuals. Observation of affected haplotypes confirmed the presence of a founder effect in the French Canadian population. Recombination analysis reduced the candidate interval to approximately 2 cM between markers D15S1040 and ACTC on chromosome 15. Linkage disequilibrium analysis suggested the gene resides nearest marker D15S1232. A physical map of the newly refined candidate region was constructed using YAC, BAC and PAC clones. These clones were used to confirm the position of candidate ESTs and genes as being either within or outside the ACCPN candidate region. / The connexin 36 gene, which was confirmed to reside within the region, was excluded as the gene responsible for ACCPN using SSCP analysis. The SLC12A6 gene was also confirmed to reside within the candidate interval and was tested for mutations using SSCP, dHPLC and sequence analyses. We found a total of four disease-specific mutations in SLC12A6, all of which are expected to truncate the KCC3 protein (the protein produced by the SLC12A6 gene). Two of the four mutations were identified in the French Canadian population; 80 French Canadian ACCPN patients are homozygous for the c.2436delG in exon 18 and one French Canadian patient is a compound heterozygote, having the c.2436delG mutation as well as the 1584_1585delCTinsG mutation in exon 11. Two additional mutations were identified in one Turkish and one Italian family in exons 22 and 15 respectively. The effects of the c.2436delG mutation on KCC3 function was studied in X. laevis oocytes and the truncated protein is not functional. Finally, collaborators at Vanderbilt University disrupted the slc12a6 gene in the mouse and found a phenotype similar to the human disease. / Identification of SLC12A6 as the gene mutated in ACCPN will allow for accurate molecular diagnosis as well as carrier testing in the French Canadian population. It is also the first step in understanding the molecular mechanism leading to the disease.

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Hand function is of great importance in the many daily activities that require well-coordinated hand and arm movements. Measurement of hand function is an essential element in the rehabilitation process, in order to facilitate medical diagnosis and determine developmental stages, functional levels, and the efficacy of treatment interventions. Basic requirements for any measurement used in clinics are that they are easy to use, relevant to the function being assessed, and valid and reliable. When scrutinizing the literature on hand function, important gaps were found with regard to measurement. For example, the reliability of grip strength with the Grippit in children has yet to be determined, and there are few evaluations of hand function measurements in Charcot-Marie-Tooth disease (CMT). Furthermore, laboratory measurements of hand function, which have the potential to provide more detailed information and insight into hand control, such as the role of the cerebellum in reactive grip control – have not been fully explored. The overall aim of the thesis was to achieve more knowledge on hand function; on the evaluation of measurements in different target populations; and on movement control of the hand. In the first study, the aim was to evaluate the test-retest reliability of the peak and sustained grip strength with Grippit in a sample of healthy children (n=58, 6-, 10- and 14-y-olds). This was followed by two studies examining hand function in an adult sample (n=20) diagnosed with CMT. The test-retest reliability of grip and pinch strength using Grippit, sensation with the Shape Texture Identification test (STI) and dexterity with the Box and Block Test (BBT) and Nine-Hole Peg test (NHP) were studied. The impact of the disease on daily life, measured with the Disability of the Arm, Shoulder and Hand questionnaire (DASH), and correlations between disability and various aspects of hand function, were also explored in this condition. The aim of the fourth study was to examine grip force response to unpredictable loadings of an object held in a pinch grip in subjects (n=9, 22-48 yrs) who had been diagnosed with a cerebellar lesion, compared with a healthy control group (n=11). The first study showed that test-retest reliability was good for both peak and sustained grip strength in healthy children. The mean and best of three trials were equally reliable, but differences in reliability were detected within different age groups. For example, the peak grip strength, best of three trials, was more reliable for the 6-y-olds (intraclass correlation coefficient (ICC)=0.96, standard error of measurement in percentage (SEM%)=6.3) and 14-y-olds (ICC=0.96, SEM%=5.2) compared with the 10-y-olds (ICC=0.78, SEM%=12.5). In the second study, evaluating measurements of hand function in subjects with CMT, grip strength proved to be reliable (ICC=0.99, coefficient of repeatability (CR)=26.7 N, coefficient of variation (CV)=6.6 %), but pinch strength was less reliable. The reliability was also good for the BBT (ICC=0.95, CR=11.5 blocks/min, CV=8.4%) and the NHP (ICC=0.99, CR=4.3 s, CV=3.9 %). However, a bias towards higher values was noted on the second test occasion with the BBT. The reliability of the STI test (kappa=0.87) was also very good in subjects with CMT. A limitation in this latter test was noted in terms of its ability to describe subjects either performing very well or very poorly. The results of the third study showed that hand function in CMT was reduced (p<0.001) to about 60% of that in healthy controls in each of the separate outcome measures, as well as by a constructed summary index of hand function. The median DASH score was 38.8 (range 0-66.7) and was clearly related to hand function (r=0.64-0.83). The results of the final study in subjects with cerebellar lesions showed that the ipsilateral hand had delayed and more variable response latencies e.g. 278±166 ms for loads delivered at 2 N/s, compared with healthy subjects (HS) 80±53 ms (p=0.005). The cerebellar subjects also used a higher pre-load grip force with the ipsilateral hand (1.6±0.8 N) than the HS (1.3±0.6 N (p=0.017)). Even the contralateral hand in subjects with unilateral cerebellar stroke showed a delayed onset of the grip response. In conclusion: Grip strength assessment in children with Grippit results in good reliability for peak and sustained grip strength, although the 10-y-olds were less reliable. In CMT the tested instruments can all be used to evaluate hand function, but certain factors, such as the number of trials used should be taken into consideration. The CMT subjects’ hand function was reduced and correlated with their self-experienced disability. However, clinicians should be aware that patients might score lower than expected on DASH, possibly due to a long process of adaptation. Cerebellar lesions can impair the reactive grip control in both the ipsilateral and the contralateral hand. These investigations have thus, as intended increased the knowledge of hand function. The studies have evaluated some measurements in different samples, which will help clinicians testing hand function.

Orientador: Anamarli Nucci / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-07T09:41:22Z (GMT). No. of bitstreams: 1 Ramos_MargotGuarieiro_M.pdf: 985606 bytes, checksum: 434d1760ad15f7e85ae84d37db9d1523 (MD5) Previous issue date: 2006 / Resumo: Charcot-Marie-Tooth (CMT) está entre as neuropatias hereditárias mais comuns, com prevalência mundial de 1:2.500 indivíduos. Constitui-se de doenças geneticamente heterogêneas, caracterizadas por atrofia e fraqueza distais dos membros inferiores, podendo estender-se para os membros superiores. Objetivos: elaborar protocolos de exame podiátrico exeqüível em nosso meio. Aplicá-los e utilizar o Escore de Neuropatia para CMT para avaliação das disfunções e sua documentação em uma amostra de pacientes do Ambulatório de Doenças Neuromusculares. Descrever o fenótipo do conjunto dos pacientes estudados. Métodos: realizou-se avaliação clínico neurológica dos pacientes, teste do suporte lateral dos pés e preencheu-se o Escore de Neuropatia para CMT. Dois protocolos de avaliação podiátrica foram elaborados, com os respectivos escores. A parte comum a ambos consistiu na avaliação da impressão plantar e da função dos plantiflexores. A parte diferencial constituiu-se na utilização de goniometria para avaliação do ângulo do tornozelo e do calcanhar em um e utilização de fotos digitalizadas para leitura dos mesmos ângulos em outro. Resultados: participaram 20 pacientes com CMT, entre 7 e 53 anos (média e mediana de 29 anos), 50% de cada sexo, 90% com CMT de herança autossômica dominante. Atrofia peroneal ocorreu em 65% dos pacientes e atrofia dos músculos intrínsecos das mãos em 50%; rigidez da articulação subtalar em 20%; pés cavos em 90%; dedos em martelo em 85%; hipertrofia dos nervos periféricos em 40%. No escore de Neuropatia para CMT encontrou-se pontuação mínima de 9 e máxima de 30. Os protocolos podiátricos resultaram em escores sem diferenças estatísticas significantes. A avaliação do ângulo do tornozelo pelo método da goniometria demonstrou pé eqüino grave em 57,5% dos membros inferiores e pelas fotos digitalizadas em 50%. Setenta e cinco por cento (75%) dos pés tinham inversão do calcanhar. A avaliação da impressão plantar diagnosticou 70% de pés cavos. Houve déficit da flexão plantar em 60% dos pacientes. Conclusões: dois escores podiátricos por métodos diferentes foram elaborados, ambos factíveis e com resultados similares. A aplicação do Escore de Neuropatia para CMT mostrou 1 paciente com incapacidade leve, 10 (50%) com incapacidade moderada e 9 (45%) com incapacidade grave. O fenótipo de atrofia peroneal com pés eqüinos graves e inversão dos calcanhares foi predominante. Palavras-chave: Charcot-Marie-Tooth, avaliação podiátrica, Escore de Neuropatia para CMT / Abstract: Charcot-Marie-Tooth (CMT) is a genetically heterogeneous group of peripheral neuropathies presenting world prevalence of 1:2.500. Atrophy and weakness of the distal lower limbs are common clinical features and these signs may extend to the upper limbs. Objectives: to elaborate reliable protocols for podiatric exams, apply them and make use of the CMT neuropathy score in a sample of outpatients of the Neuromuscular Disorders Unit at Unicamp Hospital. To describe patients phenotypes by using the mentioned tools. Methods: patients were clinically examined and test block was realized. CMT neuropathy score was fulfilled. Two protocols of podiatric evaluation were produced, resulting in two distinct scores. Both protocols had the evaluation of footprint and plantarflexors functions in common and have used different means to assess ankle and heel angles. One of them has used goniometry to assess those angles and the other has made use of digitalized photos to do the same measurement. Results: 20 CMT patients from 7 to 53 years old (being both the average age and the median value 29) were studied - 50% males and 50% females, 90% with dominant autosomal CMT. Peroneal atrophy was observed in 65% of the patients and atrophy of intrinsic hand muscles in 50%; subtalar rigidity in 20%; pes cavus in 90%; claw of toes in 85%; peripheral nerves hypertrophy in 40%. CMT neuropathy score ranged from the minimal score of 9 and the maximal of 30. There were no significant statistical differences in the results of both podiatric protocols. The evaluation of the ankle angle by goniometry showed severe footdrop in 57,5% of the lower limbs and when the digital photos were used - 50%. Seventy-five per cent (75%) of the feet showed heel inversion. Footprint method diagnosed 70% of pes cavus. Plantarflexors failure was seen in 60% of patients. Conclusions: by using different methods, two podiatric scores were elaborated - both reliable and presenting similar results. CMT neuropathy score classified 1 patient with mild disability, 10 (50%) with moderate and 9 (45%) with severe. The predominant phenotype was peroneal atrophy associated with severe footdrop and heel inversion. Key words: Charcot-Marie-Tooth, podiatric evaluation, CMT neuropathy score / Mestrado / Ciencias Biomedicas / Mestre em Ciências Médicas

Les douleurs neuropathiques se caractérisent par l’apparition de symptômes positifs tels qu’une allodynie et de symptômes négatifs tel qu’une hypoalgésie. Les douleurs neuropathiques ont un retentissement important sur la qualité de vie et il n’existe à ce jour aucune thérapie efficace pour leur prise en charge préventive. Récemment, un système rénine-angiotensine tissulaire a été mis en évidence au sein du système nerveux périphérique sensitif et il a été démontré que sa modulation pharmacologique modifie la perception douloureuse chez l’animal. Dans ce travail, nous nous sommes intéressés à la physiopathologie et à la prévention thérapeutique des neuropathies sensitives par des modulateurs du SRA. Pour cela, deux modèles murins de neuropathie sensitive à l’origine de douleurs neuropathiques ont été utilisés ; un modèle de neuropathie induite par la résinifératoxine (RTX), toxine naturelle spécifique des petites fibres nociceptives et un modèle de neuropathie induite par la vincristine (VCR), un agent anticancéreux particulièrement neurotoxique. Une étude pharmacologique menée sur la neuropathie induite par la RTX nous a permis de mettre en évidence que seul le candésartan prévenait le développement de la neuropathie et que son effet était AT2R-dépendant. L’efficacité du candésartan a été confirmée dans le modèle de neuropathie chimio-induite, développé et caractérisé au cours de ce travail. Ce modèle de neuropathie induite par la VCR a permis de révéler, pour la première fois, le potentiel neuroprotecteur du C21 (agoniste direct du récepteur AT2R, Vicore Pharma) dans un contexte de neuropathie périphérique. L’ensemble de ces résultats confirme l’intérêt de la stimulation du récepteur AT2R dans le traitement des douleurs neuropathiques associées à une chimiothérapie, et plus largement d’origine toxique. / Neuropathic pain was characterized by positive symptoms as allodynia and negative symptoms as hypoalgesia. Neuropathic pain has a major impact on patient’s quality of life and there is, currently, no specific treatment for its preventive management. Recently, a specific renin angiotensin system in sensory peripheral nervous system has been showed and it has been demonstrated that its pharmacological modulation could modify pain perception in animals. In this work, we studied the neuroprotective potential of RAS modulators in two animal models of sensory neuropathy leading to neuropathic pain; a model of neuropathy induced by resiniferatoxin (RTX), a specific natural toxin of nociceptive nerve fibers, and a model of neuropathy induced by vincristine (VCR), a neurotoxic anticancer agent. Pharmacological study on mice with RTX-induced neuropathy allowed to conclude that only candesartan was neuroprotective and that its effect was AT2R-dependent.The effective neuroprotective effect of candesartan was confirmed on the model of VCR-induced neuropathy which was previously developed and characterized. This VCR-induced neuropathy mouse model allowed to demonstrate, for the first time, that C21 (a direct AT2R receptor agonist, Vicore Pharma) was neuroprotective against a peripheral neuropathy. All these results confirm the interest of stimulation of the AT2R receptor in the treatment of neuropathic pain associated with chemotherapy and more generally of toxic origin.