Diss. (sammanfattning) Umeå : Umeå universitet, 2009. / Härtill 4 uppsatser. Även tryckt utgåva.

Les ataxies héréditaires sont des désordres neuro-dégénératifs qui causent une ataxie comme symptôme primaire; soit une perte de coordination des mouvements volontaires, un sens de l’équilibre déficient et un trouble à la motricité. Elles forment un groupe cliniquement et génétiquement hétérogène. De ce fait, de nombreuses classifications existent basées sur différents critères. Cependant, le consensus actuel veut que le mode de transmission soit le critère premier de classement. On estime la prévalence mondiale des ataxies héréditaires à 6/100 000 bien que ce nombre diffère entre régions. C’est le cas du Québec où la structuration historique du bassin génétique canadien-français a menée à des effets fondateurs régionaux, ce qui a eu comme conséquence de hausser la prévalence régionale de certaines maladies. L’Acadie est également une région canadienne-française avec des effets fondateurs où le taux de prévalence de certaines ataxies héréditaires est plus élevé. Nous avons recruté huit familles canadiennes-françaises provenant de diverses régions du Québec, ayant un lien génétique plus ou moins rapproché avec l’Acadie, dans lesquelles nous avons observé dix cas d’une forme d’ataxie spastique autosomique récessive relativement légère qui a résistée à l’analyse des gènes d’ataxies connues. Nous avons émis l’hypothèse d’être en présence d’une nouvelle forme d’ataxie à effet fondateur pour la population canadienne-française. Afin d’identifier le gène muté responsable de cette ataxie, un criblage génomique des marqueurs SNP pour les individus recrutés fut effectué. Puis, par cartographie de l’homozygotie, une région de 2,5 Mb fut identifiée sur le chromosome 17p13 dans une famille. Une revue de la littérature nous a permis de constater, qu’en 2007, quatre familles nord-africaines atteintes d’une ataxie dénommée SPAX2 qui présentaient des manifestations cliniques semblables avaient déjà été liées au même locus sur le chromosome 17. Afin de supporter notre hypothèse que les malades étaient porteurs de deux copies de la même mutation fondatrice et de cartographier plus finement notre région d’intérêt, les haplotypes de tous les atteints de nos huit familles furent étudiés. Nous avons établie qu’un intervalle de 200 kb (70 SNP), soit du marqueur rs9900036 à rs7222052, était partagé par tous nos participants. Les deux gènes les plus prometteurs des 18 se trouvant dans la région furent séquencés. Aucune mutation ne fut trouvée dans les gènes SLC25A11 et KIF1C. Par la suite, une analyse de liaison génétique stricte avec calcul de LOD score nous a permis d’exclure ce locus de 200 kb comme étant celui porteur du gène muté causant l’ataxie dans la majorité de nos familles. Nous avons donc conclus que malgré qu’une famille soit homozygote pour une grande région du chromosome 17, l’absence d’Informativité des marqueurs SNP dans la région de 200 kb fut responsable de l’apparent partage d’haplotype homozygote. Le travail reste donc entier afin d’identifier les mutations géniques responsables de la présentation ataxique chez nos participants de souche acadienne. / Hereditary ataxias are neurodegenerative disorders which share ataxia as common feature is manifested by a decrease in limb coordination, imbalance and an unsteady gait. They consist in a clinically and genetically heterogeneous group. Many ataxia classifications have been proposed, however, the current consensus is to first characterize them according to their mode of transmission. Hereditary ataxias as a whole have a prevalence of 6/100 000, with variable estimation between country and region. In the Province of Quebec where the French Canadian genetic pool can be seen has a mosaic of regional gene pools there is clear differences in local variation in the prevalence of different ataxias. Acadia is also a French Canadian region with a history of many founder effects and a higher prevalence for certain hereditary ataxias. We recruit 8 French Canadian families from Quebec and with genealogical links with Acadia in which 10 cases manifest a presumably relatively mild autosomal recessive spastic ataxia of unknown etiology. The shared phenotype and Acadian background raised the possibility that they suffered from a new form of ataxia with a founder effect. To identify the mutated gene causing this ataxia, the individuals recruited were genotyped. By homozygosity mapping, a region of 2,5 Mb was identified in one family on chromosome 17p13. A literature review established that in 2007 four North Africans families segregating also a mild spastic ataxia were linked to the same locus on chromosome 17. To support our hypothesis that our patients were carrier of the same founder mutation we look closer at their haplotype in the region. We defined an interval of 200kb (70 SNP) between markers rs9900036 and rs7222052 shared by all affected cases. The two most promising gene in the interval were sequenced. No mutation was found in SLC25A11 and KIF1C. Thereafter a linkage analysis by LOD score excluded the candidate interval of 200 kb in the majority of our families. We conclude that even if in one family exists a large homozygous region on chromosome 17, the lack of informative SNP in the 200 kb region was responsible for the apparent sharing rather than they shared a common mutation. Further work will be necessary to identify the mutate gene causing the ataxia presentation in these cases of mild spastic ataxia.

Neurodegenerative disorders are heterogenous in nature and include a range of ataxias with oculomotor apraxia, which are characterised by a wide variety of neurological and ophthalmological features. This family includes recessive and dominant disorders. A subfamily of autosomal recessive cerebellar ataxias are characterised by defects in the cellular response to DNA damage. These include the well characterised disorders Ataxia-Telangiectasia (A-T) and Ataxia-Telangiectasia Like Disorder (A-TLD) as well as the recently identified diseases Spinocerebellar ataxia with axonal neuropathy Type 1 (SCAN1), Ataxia with Oculomotor Apraxia Type 2 (AOA2), as well as the subject of this thesis, Ataxia with Oculomotor Apraxia Type 1 (AOA1). AOA1 is caused by mutations in the APTX gene, which is located at chromosomal locus 9p13. This gene codes for the 342 amino acid protein Aprataxin. Mutations in APTX cause destabilization of Aprataxin, thus AOA1 is a result of Aprataxin deficiency. Aprataxin has three functional domains, an N-terminal Forkhead Associated (FHA) phosphoprotein interaction domain, a central Histidine Triad (HIT) nucleotide hydrolase domain and a C-terminal C2H2 zinc finger. Aprataxins FHA domain has homology to FHA domain of the DNA repair protein 5’ polynucleotide kinase 3’ phosphatase (PNKP). PNKP interacts with a range of DNA repair proteins via its FHA domain and plays a critical role in processing damaged DNA termini. The presence of this domain with a nucleotide hydrolase domain and a DNA binding motif implicated that Aprataxin may be involved in DNA repair and that AOA1 may be caused by a DNA repair deficit. This was substantiated by the interaction of Aprataxin with proteins involved in the repair of both single and double strand DNA breaks (XRay Cross-Complementing 1, XRCC4 and Poly-ADP Ribose Polymerase-1) and the hypersensitivity of AOA1 patient cell lines to single and double strand break inducing agents. At the commencement of this study little was known about the in vitro and in vivo properties of Aprataxin. Initially this study focused on generation of recombinant Aprataxin proteins to facilitate examination of the in vitro properties of Aprataxin. Using recombinant Aprataxin proteins I found that Aprataxin binds to double stranded DNA. Consistent with a role for Aprataxin as a DNA repair enzyme, this binding is not sequence specific. I also report that the HIT domain of Aprataxin hydrolyses adenosine derivatives and interestingly found that this activity is competitively inhibited by DNA. This provided initial evidence that DNA binds to the HIT domain of Aprataxin. The interaction of DNA with the nucleotide hydrolase domain of Aprataxin provided initial evidence that Aprataxin may be a DNA-processing factor. Following these studies, Aprataxin was found to hydrolyse 5’adenylated DNA, which can be generated by unscheduled ligation at DNA breaks with non-standard termini. I found that cell extracts from AOA1 patients do not have DNA-adenylate hydrolase activity indicating that Aprataxin is the only DNA-adenylate hydrolase in mammalian cells. I further characterised this activity by examining the contribution of the zinc finger and FHA domains to DNA-adenylate hydrolysis by the HIT domain. I found that deletion of the zinc finger ablated the activity of the HIT domain against adenylated DNA, indicating that the zinc finger may be required for the formation of a stable enzyme-substrate complex. Deletion of the FHA domain stimulated DNA-adenylate hydrolysis, which indicated that the activity of the HIT domain may be regulated by the FHA domain. Given that the FHA domain is involved in protein-protein interactions I propose that the activity of Aprataxins HIT domain may be regulated by proteins which interact with its FHA domain. We examined this possibility by measuring the DNA-adenylate hydrolase activity of extracts from cells deficient for the Aprataxin-interacting DNA repair proteins XRCC1 and PARP-1. XRCC1 deficiency did not affect Aprataxin activity but I found that Aprataxin is destabilized in the absence of PARP-1, resulting in a deficiency of DNA-adenylate hydrolase activity in PARP-1 knockout cells. This implies a critical role for PARP-1 in the stabilization of Aprataxin. Conversely I found that PARP-1 is destabilized in the absence of Aprataxin. PARP-1 is a central player in a number of DNA repair mechanisms and this implies that not only do AOA1 cells lack Aprataxin, they may also have defects in PARP-1 dependant cellular functions. Based on this I identified a defect in a PARP-1 dependant DNA repair mechanism in AOA1 cells. Additionally, I identified elevated levels of oxidized DNA in AOA1 cells, which is indicative of a defect in Base Excision Repair (BER). I attribute this to the reduced level of the BER protein Apurinic Endonuclease 1 (APE1) I identified in Aprataxin deficient cells. This study has identified and characterised multiple DNA repair defects in AOA1 cells, indicating that Aprataxin deficiency has far-reaching cellular consequences. Consistent with the literature, I show that Aprataxin is a nuclear protein with nucleoplasmic and nucleolar distribution. Previous studies have shown that Aprataxin interacts with the nucleolar rRNA processing factor nucleolin and that AOA1 cells appear to have a mild defect in rRNA synthesis. Given the nucleolar localization of Aprataxin I examined the protein-protein interactions of Aprataxin and found that Aprataxin interacts with a number of rRNA transcription and processing factors. Based on this and the nucleolar localization of Aprataxin I proposed that Aprataxin may have an alternative role in the nucleolus. I therefore examined the transcriptional activity of Aprataxin deficient cells using nucleotide analogue incorporation. I found that AOA1 cells do not display a defect in basal levels of RNA synthesis, however they display defective transcriptional responses to DNA damage. In summary, this thesis demonstrates that Aprataxin is a DNA repair enzyme responsible for the repair of adenylated DNA termini and that it is required for stabilization of at least two other DNA repair proteins. Thus not only do AOA1 cells have no Aprataxin protein or activity, they have additional deficiencies in PolyADP Ribose Polymerase-1 and Apurinic Endonuclease 1 dependant DNA repair mechanisms. I additionally demonstrate DNA-damage inducible transcriptional defects in AOA1 cells, indicating that Aprataxin deficiency confers a broad range of cellular defects and highlighting the complexity of the cellular response to DNA damage and the multiple defects which result from Aprataxin deficiency. My detailed characterization of the cellular consequences of Aprataxin deficiency provides an important contribution to our understanding of interlinking DNA repair processes.

The aetiological diagnosis of recessive non-syndromic hearing loss poses a challenge owing to marked heterogeneity and the lack of identifying clinical features. The finding that up to 50% of recessive non-syndromal genetic hearing loss among Caucasians was due to mutations in GJB2, the gene encoding Connexin 26 (Cx26) was a breakthrough, whose value as a diagnostic tool has been limited by the significant variation in the prevalence of deafness genes and loci among population groups. The significant association of the GJB6-D13S1830 deletion among individuals with one mutant GJB2 allele highlighted the need to explore population specific genetic mutations for NSHL. Although data from Sub-Saharan Africa is limited, reported studies found a high prevalence of R143W GJB2 mutation among Ghanaian, the 35delG mutation in 5 out of 139 Sudanese and a low prevalence of GJB2 variations among 385 Kenyan deaf children. The mutation spectrum of Waardenburg Syndrome (WS) in Africans has not been documented. During a visit to a School for the Deaf in the Limpopo Province of South Africa in 1997, it was noted that a high number of students came from Nzhelele sub-district. All had childhood onset hearing loss with no associated anomalies or disorders. The question arose as to whether there was a high-risk area for deafness in the Limpopo Province and what the aetiology of this hearing loss was.The main aim of this study was to investigate the role of GJB2, the GJB6-D13S1830 deletion, and the four common mitochondrial mutations, A1555G, A3243G, A7511C and A7445G, in the African hearing-impaired population of Limpopo province in South Africa, and to identify the mutation spectrum of the deafness genes found. The type and degree of hearing loss in this hearing impaired population would also be assessed. Secondly, this study sought to identify the mutations in a sibling pair with 2 clinical WS and to use the findings in a future study to establish the mutation spectrum of WS in the African population of the Limpopo province and of South Africa in general. The study was designed as a two phase study, in which phase 1 was used for hypothesis formulation and phase 2 was for hypothesis testing. While phase 1 was a descriptive retrospective case study, phase 2 was a combination of sample survey and prospective descriptive case study. In phase 1, demographic data of 361 students in two schools of the deaf in the Limpopo province was analyzed for evidence of areas of high risk populations for deafness in the province. In phase 2, a group of 182 individuals with genetic non-syndromic hearing loss (NSHL) and two siblings with clinical WS from two schools for the Deaf in the Limpopo Province of South Africa were investigated. A thorough clinical examination, audiological evaluation and urinalysis were done. Mutational screening was carried out in all 184 subjects using genomic DNA using single-strand conformation polymorphism (SSCP), multiplex polymerase chain reaction (PCR), and direct sequencing for GJB2, and Restriction Fragment-Length Polymorphism (PCR–RFLP) analysis for GJB6, and SSCP, hetero-duplex analysis, and direct sequencing of the first 8 exons of PAX3 and all of MITF for Waarenburg syndrome. Data analysis was by geographical mapping, frequency tables, tests of association with calculation of odds ratios, and binary logistic regression analysis using STATA and GIS mapping systems. The results indicate that there seem to be areas of genuine populations at risk for hearing loss in the Limpopo province of South Africa, namely Mutale and parts of Makhado and Thulamela municipalities. In Thulamela (NP343) wards 11-15, 26-30 and 31-35, and in Mutale (NP 344) wards 6-10, together accounted for 67 (18%) of participants in phase 1, and 33 (18%) of the participants in phase 2 of the study. Mutale municipality in the Vhembe 3 district gave with a projected prevalence of at least 13.14 deaf children per 100,000 African population attending the local school for the deaf. The observed hearing loss is a genetic, non-syndromic form, which is mainly severe and severe to profound, although without any clear defining configuration or shape. It is a stable, non-progressive and prelingual form of hearing loss, implying that this may be a recessive form of deafness. No identifiable environmental confounding factors or associations were identified. The deafness is not linked the common known auditory gene mutations in GJB2, the GJB6-D13S1830 deletion, or the common mitochondrial mutations A1555G, A3243G, A7511C and A7445G. Severe and profound levels of hearing loss were found in 22.8% and 75% of the cohort respectively, with the majority exhibiting flat (70.1%) or sloping (23.4%) audiograms that were commonly symmetrical (81.5%). However, as indicated, there was no clear pattern in the audiological findings overall. None of the 184 hearing impaired individuals exhibited any of the reported disease causing mutations of GJB2, including 35delG. There was, however, a high prevalence of two variants, the C>T variant at position g.3318-15 and the C>T variant at position g.3318-34, occurring in 21.4% and 46.2% of the deaf cohort respectively. The same variants were found to occur in 35% and 42.6% of a normal hearing control group (n = 63) respectively, indicating that these variations are polymorphisms. In three subjects (1.63% of the cohort), a T>A homozygous variation at position g.3318-6 was detected. Its significance in the causation of NSSNHL is yet to be determined. The GJB6-D13S1830 deletion was not detected in any of the participants. None of the four mitochondrial mutations screened for were found. 4 These results indicate that GJB2 is not a significant deafness gene in the African population of the Limpopo Province of South Africa and that significant genes for non-syndromic recessive hearing loss in this population are yet to be found. The geographical clustering of deafness found in this study, combined with the lack of identifiable common associated clinical features among the subjects of this study (excluding the WS sibling pair), suggests that these subjects have a genetic recessive non-syndromal type of hearing loss. In the context of historical and cultural evidence of consanguinity in this population, a founder effect cannot be ruled out. A rare mutation, R223X, previously identified only once out of 470 WS patients, was identified in the PAX3 gene among the WS sibling pair. A novel silent change GGG>GGT at amino acid 293, was also identified. These identical findings document, for the first time, a molecular defect in WS in an African sibling pair, and confirm WS Type I in this family, which could be found in other WS type I South Africans in the Limpopo Province of South Africa. The current study demonstrated that parents of genetically hearing impaired children in these areas are able to detect hearing loss at an early age, with over 60% suspecting their children’s hearing loss below 6 months of age. A child-centered management model encompassing all the areas relevant to childhood deafness/hearing impairment, which takes into consideration the prevailing logistical and financial constraints of the available healthcare system, is proposed. The implementation of this model requires a paradigm shift from the current fragmented model of service delivery to a cohesive patient-centered approach, based on concrete data from appropriate community based research, in which all the relevant parties communicate and share resources. 5 It would achieve the goals of early detection and intervention, as well as inclusive education for all. The relevant health and education policies are already in place and the posts funded. Equitable implementation of these policies would require appropriate community based research, as well as improved communication and consultation between the various stakeholders to ensure an efficient and affordable quality healthcare service for all hearing impaired South Africans.

Introdução: A síndrome SPOAN é uma doença neurodegenerativa, de transmissão genética autossômica recessiva, até o momento reconhecida apenas no Brasil, que caracteriza-se por: paraplegia espástica, de início nos primeiros anos de vida e caráter progressivo; atrofia óptica congênita; neuropatia periférica sensitivo-motora axonal, de início a partir da primeira década de vida; sobressaltos à estimulação sonora, disartria, deformidades de coluna e pés e sinais extra piramidais. A sua caracterização foi feita por nosso grupo, que avaliou clinicamente 71 indivíduos, originários do Rio Grande do Norte. Estudo de ligação mapeou o locus responsável pela síndrome SPOAN em uma região de 2 Mb no cromossomo 11q13. O gene responsável pela síndrome SPOAN permanece desconhecido. A síndrome SPOAN é considerada uma forma complicada de paraplegia espástica. A associação entre neuropatia e paraplegia espástica está relacionada à perda progressiva de axônios longos e tem sido relatada em algumas formas complicadas de neuropatias e paraplegias espásticas hereditárias. Casuística e métodos: Foi realizada a avaliação de 27 pacientes, 20 mulheres, com idade variando entre 4 e 58 anos. Todos os indivíduos compartilhavam o mesmo fenótipo (paraplegia espástica, atrofia de nervo óptico e neuropatia periférica) e tinham o mesmo haplótipo 11q13. Pacientes com história de diabetes mellitus ou alcoolismo foram excluídos do estudo. A avaliação neurológica incluiu a pesquisa dos escores modificados de sintomas e comprometimento neuropáticos. A força muscular foi testada e graduada conforme a escala MRC (Medical Research Council). Foi realizada a pesquisa da sensibilidade dolorosa, térmica, tátil, vibratória e artrestésica. O trofismo foi avaliado pela presença de deformidades na coluna e atrofia nos membros inferiores. Os reflexos profundos e o cutâneo plantar também foram analisados. Os estudos da condução nervosa foram realizados em um aparelho portátil Nicolet - Viking Quest, (Viasys, USA). Para os estudos de condução motora foram analisados os nervos axillar, mediano, ulnar, femoral, tibial e fibular direito. A condução sensitiva foi analisada nos nervos mediano, ulnar, radial, sural e fibular direito. O reflexo H e as ondas F foram avaliados com técnicas padrão. Alguns testes não puderam ser realizados devido à intensa atrofia e deformidades esqueléticas. O coeficiente de correlação de Pearson foi calculado entre a idade e os parâmetros, velocidade de condução, latência e amplitude. Valores de P < 0,05 foram considerados estatisticamente significantes. Resultados: Avaliação clínica: Todos os pacientes obtiveram escore de sinais neuropáticos graves e demonstraram déficit de força e atrofia distal. Deformidades dos pés estavam presentes em todos os pacientes e deformidades na coluna, em 58%. Os reflexos profundos dos membros superiores estavam exaltados em 92% dos casos e o reflexo patelar, em 63%. O reflexo Aquileu estava ausente em todos os pacientes. Todas as modalidades de sensibilidade foram afetadas, principalmente nos membros inferiores. Os dados do exame de sensibilidade na paciente de 4 anos foram desconsiderados. Estudo da condução nervosa sensitiva: Os SNAPs dos nervos mediano, sural e fibular estavam ausentes em todos os pacientes. SNAPs do nervo ulnar estavam ausentes em 96% da amostra e do nervo radial, em 80%. Estudo da condução nervosa motora: As latências motoras dos nervos axilar e femoral estavam normais em todos os pacientes. As amplitudes dos CMAPs estavam reduzidas em 15 e 52% da amostra nos nervos mediano e ulnar, respectivamente. Velocidades de condução estavam reduzidas em 50 e 41% desta casuística nos nervos mediano e ulnar, respectivamente. Velocidades de condução estavam acima de 80% do limite inferior da normalidade, em todos os nervos, exceto em 1 paciente que apresentou redução de 27% no nervo ulnar. Entretanto, este mesmo paciente apresentou amplitude menor que 2mV. Ondas F apresentavam aumento da latência, de acordo com a altura, em 100% dos casos. CMAPs estavam ausentes em 93 e 84% da amostra nos nervos fibular e tibial, respectivamente. Reflexo H estava ausente em 88% dos pacientes. Não houve correlação entre idade e a velocidade de condução, latência e amplitude dos nervos mediano e ulnar. Discussão: O estudo da condução nervosa neste grupo preencheu critérios para uma neuropatia primária axonal. Nenhum paciente apresentou bloqueio de condução ou dispersão temporal. As alterações encontradas na velocidade de condução provavelmente se devem à perda de fibras nervosas de condução rápida. Fenótipos SPOAN-like foram descritos em famílias com mutações nos genes C12orf65, TFG e OPA1. No entanto, não existem detalhes sobre a condução nervosa nestes pacientes. Neuropatia axonal de início tardio foi relacionada à SPG55 e DOA (dominant optic atrophy), enquanto neuropatia axonal e desmielinizante com leve comprometimento sensitivo foi descrita na família com mutação no gene TFG. Conclusão: Os pacientes com a síndrome SPOAN apresentam uma acentuada neuropatia axonal, sensitivo motora. As alterações encontradas na condução nervosa dos pacientes com síndrome SPOAN não são específicas, no entanto, resultados normais excluem esta condição em adultos. A paciente mais jovem desta casuística já apresentava alterações ao exame, o que pode sugerir um início precoce da neuropatia. Entretanto, não temos dados suficientes para afirmar que este seja um achado comum a todos os pacientes SPOAN / Introduction: SPOAN syndrome (Spastic Paraplegia, Optic Atrophy and Neuropathy) is a progressive neurodegenerative disorder of autosomal recessive inheritance described by our group in a large inbred family from Northeastern Brazil. The clinical picture is characterized by non-progressive congenital optic atrophy, progressive spastic paraplegia, axonal neuropathy, auditory startles, dysarthria, spinal and foot deformities and also extrapyramidal signs. Linkage studies mapped the responsible locus for the syndrome to a 2Mb region on chromosome 11q13. The gene responsible for SPOAN syndrome remains elusive. Materials and Methods: This is a cross sectional study which was conducted from 2009 to 2011. We evaluated 27 patients (20 females), with a0ges ranging from 4 to 58 years. All patients shared the same phenotype (spastic paraplegia, optic atrophy and peripheral neuropathy) and had the same 11q13 haplotype in homozygosis. Patients with history of diabetes mellitus or alcoholism were excluded from this study. All patients were evaluated by the same clinical researcher (SA). Neurological evaluation included determination of modified neuropathy symptoms (NSS) and neuropathy disability (NDS) scores. Motor strength was assessed using MRC scale. Sensibility assessment included small-fiber (pain and temperature) and large-fiber modalities (vibration-128Hz diapason, 10g monofilament and joint position sense). Spine deformities and atrophy in the lower limbs were observed. We also evaluated osteotendineous reflexes and cutaneous plantar reflexes. Nerve conduction studies were performed using a portable Nicolet - Viking Quest, (Viasys,USA). Motor conduction studies included axillary, median, ulnar, femoral, tibial and fibular nerves on the right side. Sensory nerve action potentials of median, ulnar, sural and superficial fibular nerves were recorded using a bar electrode of 3 cm and standard fixed distances. Tibial H-reflex was evaluated with standard technique. Minimal F wave latencies were obtained from ulnar and tibial nerves. A few tests could not be done in every patient due to severe deformities. We calculated Pearson\'s correlation coefficients between age and nerve conduction parameters, including velocities, latencies and amplitudes. P values <0.05 were considered statistically significant. Results: Clinical data: Neuropathic symptoms such as pain and paresthesias were rare. All patients had signs of severe neuropathy. All subjects demonstrated weakness and atrophy that were more significant distally than proximally. Foot deformities were present in all patients and spine deformities were seen in 58%. Upper limb deep tendon reflexes were exalted in 92% and patelar reflex in 63%. Ankle reflex was absent in all patients. In one patient, who was 4 years-old, sensory evaluation was inconsistent and the results were not considered. In all the other ones, sensory modalities were affected and occurred predominantly in the lower limbs. Electrodiagnostic data: Sensory nerve conduction: Median nerve SNAP was absent in all 27 patients. Ulnar nerve SNAPs were absent in 96%, whereas radial nerve SNPAs were absent in 80%. Superficial fibular and sural SNAPs were absent in all patients. Motor nerve conduction: The motor latencies of axillary and femoral nerves were normal in all patients. CMAP amplitudes were reduced in 15% of the median nerves and in 52% of the ulnar nerves. Conduction velocities (CV) were reduced in 50% of the median nerves and in 41% of the ulnar nerves. CV was above 80% of the lower normal limit for all nerves, except for one patient who showed a 27% reduction of ulnar CV, but had also a CMAP amplitude of less than 2 mV. F waves were prolonged according to the height in 100%. Only one patient who presented significant motor CV reduction of the ulnar nerve. CMAPs were absent in 93% of the fibular nerves and in 84% of the tibial nerves. A single fibular nerve showed more than 20% of CV reduction, but also had severely reduced CMAP amplitude. H reflex was absent in 88% of the patients. There was no correlation between age and neurophysiological parameters, such as median or ulnar CV, latencies or CMAP amplitudes. Discussion: Nerve conduction studies in this group fulfill criteria for primary axonal neuropathy. No patient showed conduction block or temporal dispersion. Abnormalities seen in CV and F waves are probably related to loss of fast conduction fiber nerves. We could not demonstrate correlation between age and nerve conduction parameters, including velocities, latencies and amplitudes. SPOAN-like phenotype has been found in families with mutations in C12orf65, TFG and OPA1 genes, however there is no detailed report on nerve conduction studies in these conditions. Axonal neuropathy is also described in SPG55 and DOA plus, but usually with a later onset than on SPOAN syndrome. Peripheral neuropathy is also described in the family with mutation in TFG gene, but this presents a different pattern characterized as a mixed axonal demyelinating neuropathy with mild sensory involvement. Although the nerve conduction abnormalities seen in SPOAN syndrome are not specific, normal results seem to rule out this condition, at least in adult patients. The younger patient in our series was 4-years-old, and her neurophysiological study was severely abnormal, suggesting an early-onset neuropathy. However, we do not have a comprehensive study of several young patients to support that this feature is

Introdução: A síndrome SPOAN é uma doença neurodegenerativa, de transmissão genética autossômica recessiva, até o momento reconhecida apenas no Brasil, que caracteriza-se por: paraplegia espástica, de início nos primeiros anos de vida e caráter progressivo; atrofia óptica congênita; neuropatia periférica sensitivo-motora axonal, de início a partir da primeira década de vida; sobressaltos à estimulação sonora, disartria, deformidades de coluna e pés e sinais extra piramidais. A sua caracterização foi feita por nosso grupo, que avaliou clinicamente 71 indivíduos, originários do Rio Grande do Norte. Estudo de ligação mapeou o locus responsável pela síndrome SPOAN em uma região de 2 Mb no cromossomo 11q13. O gene responsável pela síndrome SPOAN permanece desconhecido. A síndrome SPOAN é considerada uma forma complicada de paraplegia espástica. A associação entre neuropatia e paraplegia espástica está relacionada à perda progressiva de axônios longos e tem sido relatada em algumas formas complicadas de neuropatias e paraplegias espásticas hereditárias. Casuística e métodos: Foi realizada a avaliação de 27 pacientes, 20 mulheres, com idade variando entre 4 e 58 anos. Todos os indivíduos compartilhavam o mesmo fenótipo (paraplegia espástica, atrofia de nervo óptico e neuropatia periférica) e tinham o mesmo haplótipo 11q13. Pacientes com história de diabetes mellitus ou alcoolismo foram excluídos do estudo. A avaliação neurológica incluiu a pesquisa dos escores modificados de sintomas e comprometimento neuropáticos. A força muscular foi testada e graduada conforme a escala MRC (Medical Research Council). Foi realizada a pesquisa da sensibilidade dolorosa, térmica, tátil, vibratória e artrestésica. O trofismo foi avaliado pela presença de deformidades na coluna e atrofia nos membros inferiores. Os reflexos profundos e o cutâneo plantar também foram analisados. Os estudos da condução nervosa foram realizados em um aparelho portátil Nicolet - Viking Quest, (Viasys, USA). Para os estudos de condução motora foram analisados os nervos axillar, mediano, ulnar, femoral, tibial e fibular direito. A condução sensitiva foi analisada nos nervos mediano, ulnar, radial, sural e fibular direito. O reflexo H e as ondas F foram avaliados com técnicas padrão. Alguns testes não puderam ser realizados devido à intensa atrofia e deformidades esqueléticas. O coeficiente de correlação de Pearson foi calculado entre a idade e os parâmetros, velocidade de condução, latência e amplitude. Valores de P < 0,05 foram considerados estatisticamente significantes. Resultados: Avaliação clínica: Todos os pacientes obtiveram escore de sinais neuropáticos graves e demonstraram déficit de força e atrofia distal. Deformidades dos pés estavam presentes em todos os pacientes e deformidades na coluna, em 58%. Os reflexos profundos dos membros superiores estavam exaltados em 92% dos casos e o reflexo patelar, em 63%. O reflexo Aquileu estava ausente em todos os pacientes. Todas as modalidades de sensibilidade foram afetadas, principalmente nos membros inferiores. Os dados do exame de sensibilidade na paciente de 4 anos foram desconsiderados. Estudo da condução nervosa sensitiva: Os SNAPs dos nervos mediano, sural e fibular estavam ausentes em todos os pacientes. SNAPs do nervo ulnar estavam ausentes em 96% da amostra e do nervo radial, em 80%. Estudo da condução nervosa motora: As latências motoras dos nervos axilar e femoral estavam normais em todos os pacientes. As amplitudes dos CMAPs estavam reduzidas em 15 e 52% da amostra nos nervos mediano e ulnar, respectivamente. Velocidades de condução estavam reduzidas em 50 e 41% desta casuística nos nervos mediano e ulnar, respectivamente. Velocidades de condução estavam acima de 80% do limite inferior da normalidade, em todos os nervos, exceto em 1 paciente que apresentou redução de 27% no nervo ulnar. Entretanto, este mesmo paciente apresentou amplitude menor que 2mV. Ondas F apresentavam aumento da latência, de acordo com a altura, em 100% dos casos. CMAPs estavam ausentes em 93 e 84% da amostra nos nervos fibular e tibial, respectivamente. Reflexo H estava ausente em 88% dos pacientes. Não houve correlação entre idade e a velocidade de condução, latência e amplitude dos nervos mediano e ulnar. Discussão: O estudo da condução nervosa neste grupo preencheu critérios para uma neuropatia primária axonal. Nenhum paciente apresentou bloqueio de condução ou dispersão temporal. As alterações encontradas na velocidade de condução provavelmente se devem à perda de fibras nervosas de condução rápida. Fenótipos SPOAN-like foram descritos em famílias com mutações nos genes C12orf65, TFG e OPA1. No entanto, não existem detalhes sobre a condução nervosa nestes pacientes. Neuropatia axonal de início tardio foi relacionada à SPG55 e DOA (dominant optic atrophy), enquanto neuropatia axonal e desmielinizante com leve comprometimento sensitivo foi descrita na família com mutação no gene TFG. Conclusão: Os pacientes com a síndrome SPOAN apresentam uma acentuada neuropatia axonal, sensitivo motora. As alterações encontradas na condução nervosa dos pacientes com síndrome SPOAN não são específicas, no entanto, resultados normais excluem esta condição em adultos. A paciente mais jovem desta casuística já apresentava alterações ao exame, o que pode sugerir um início precoce da neuropatia. Entretanto, não temos dados suficientes para afirmar que este seja um achado comum a todos os pacientes SPOAN / Introduction: SPOAN syndrome (Spastic Paraplegia, Optic Atrophy and Neuropathy) is a progressive neurodegenerative disorder of autosomal recessive inheritance described by our group in a large inbred family from Northeastern Brazil. The clinical picture is characterized by non-progressive congenital optic atrophy, progressive spastic paraplegia, axonal neuropathy, auditory startles, dysarthria, spinal and foot deformities and also extrapyramidal signs. Linkage studies mapped the responsible locus for the syndrome to a 2Mb region on chromosome 11q13. The gene responsible for SPOAN syndrome remains elusive. Materials and Methods: This is a cross sectional study which was conducted from 2009 to 2011. We evaluated 27 patients (20 females), with a0ges ranging from 4 to 58 years. All patients shared the same phenotype (spastic paraplegia, optic atrophy and peripheral neuropathy) and had the same 11q13 haplotype in homozygosis. Patients with history of diabetes mellitus or alcoholism were excluded from this study. All patients were evaluated by the same clinical researcher (SA). Neurological evaluation included determination of modified neuropathy symptoms (NSS) and neuropathy disability (NDS) scores. Motor strength was assessed using MRC scale. Sensibility assessment included small-fiber (pain and temperature) and large-fiber modalities (vibration-128Hz diapason, 10g monofilament and joint position sense). Spine deformities and atrophy in the lower limbs were observed. We also evaluated osteotendineous reflexes and cutaneous plantar reflexes. Nerve conduction studies were performed using a portable Nicolet - Viking Quest, (Viasys,USA). Motor conduction studies included axillary, median, ulnar, femoral, tibial and fibular nerves on the right side. Sensory nerve action potentials of median, ulnar, sural and superficial fibular nerves were recorded using a bar electrode of 3 cm and standard fixed distances. Tibial H-reflex was evaluated with standard technique. Minimal F wave latencies were obtained from ulnar and tibial nerves. A few tests could not be done in every patient due to severe deformities. We calculated Pearson\'s correlation coefficients between age and nerve conduction parameters, including velocities, latencies and amplitudes. P values <0.05 were considered statistically significant. Results: Clinical data: Neuropathic symptoms such as pain and paresthesias were rare. All patients had signs of severe neuropathy. All subjects demonstrated weakness and atrophy that were more significant distally than proximally. Foot deformities were present in all patients and spine deformities were seen in 58%. Upper limb deep tendon reflexes were exalted in 92% and patelar reflex in 63%. Ankle reflex was absent in all patients. In one patient, who was 4 years-old, sensory evaluation was inconsistent and the results were not considered. In all the other ones, sensory modalities were affected and occurred predominantly in the lower limbs. Electrodiagnostic data: Sensory nerve conduction: Median nerve SNAP was absent in all 27 patients. Ulnar nerve SNAPs were absent in 96%, whereas radial nerve SNPAs were absent in 80%. Superficial fibular and sural SNAPs were absent in all patients. Motor nerve conduction: The motor latencies of axillary and femoral nerves were normal in all patients. CMAP amplitudes were reduced in 15% of the median nerves and in 52% of the ulnar nerves. Conduction velocities (CV) were reduced in 50% of the median nerves and in 41% of the ulnar nerves. CV was above 80% of the lower normal limit for all nerves, except for one patient who showed a 27% reduction of ulnar CV, but had also a CMAP amplitude of less than 2 mV. F waves were prolonged according to the height in 100%. Only one patient who presented significant motor CV reduction of the ulnar nerve. CMAPs were absent in 93% of the fibular nerves and in 84% of the tibial nerves. A single fibular nerve showed more than 20% of CV reduction, but also had severely reduced CMAP amplitude. H reflex was absent in 88% of the patients. There was no correlation between age and neurophysiological parameters, such as median or ulnar CV, latencies or CMAP amplitudes. Discussion: Nerve conduction studies in this group fulfill criteria for primary axonal neuropathy. No patient showed conduction block or temporal dispersion. Abnormalities seen in CV and F waves are probably related to loss of fast conduction fiber nerves. We could not demonstrate correlation between age and nerve conduction parameters, including velocities, latencies and amplitudes. SPOAN-like phenotype has been found in families with mutations in C12orf65, TFG and OPA1 genes, however there is no detailed report on nerve conduction studies in these conditions. Axonal neuropathy is also described in SPG55 and DOA plus, but usually with a later onset than on SPOAN syndrome. Peripheral neuropathy is also described in the family with mutation in TFG gene, but this presents a different pattern characterized as a mixed axonal demyelinating neuropathy with mild sensory involvement. Although the nerve conduction abnormalities seen in SPOAN syndrome are not specific, normal results seem to rule out this condition, at least in adult patients. The younger patient in our series was 4-years-old, and her neurophysiological study was severely abnormal, suggesting an early-onset neuropathy. However, we do not have a comprehensive study of several young patients to support that this feature is

Autosomal recessive polycystic kidney disease (ARPKD) is a rare severe inherited disease manifested by cystic renal disease, congenital hepatic fibrosis and dilatatation of bile ducts. The spectrum of clinical manifestations is very wide and variable, depends on the age at which the disease was manifested. In severe forms of the disease, it is possible to detect the first symptoms prenatally around the 20th week of pregnancy due to increased echogenic kidneys and the presence of oligohydramnios. The causal gene of this disease is thePKHD1 gene with protein product fibrocystin that is most likely contributing on maintaining the intracellular concentration of Ca2+ cations. The exact phatophysiology mechanism of ARPKD remains unknown. Phenotypic manifestations of this disease may overlap with mutations associated with other genes. One of the genes mimicking the ARPKD phenotype is the HNF1B gene. Mutations associated with HNF1B gene are the most common monogenic cause of developmental kidney abnormalities. HNF1B is a tissue-specific transcription factor that regulates the expression of PKHD1. In experimental part I worked on genetic analysis of the HNF1B gene in 28 patients who have not been confirmed ARPKD diagnosis by detection of 2 PKHD1 mutations. For the purposes of mutational screening, I used...

Bibliography: leaves 653-669 / Before God created human beings, He devised a plan to save them in case they sinned. In this plan, the second Person of the Godhead would become human. Thus, the incarnation of the second Person of the Godhead was solely for the purpose of saving fallen, sinful human beings. There would have been no incarnation if human beings had not sinned. Thus, the nature of the mission that necessitated the incarnation determined what kind of human nature Jesus was to assume. It was sin that necessitated the incarnation – sin as a tendency and sin as an act of disobedience. In His incarnational life and later through His death on Calvary’s cross, Jesus needed to deal with this dual problem of sin. In order for Him to achieve this, He needed to identify Himself with the fallen humanity in such a way that He would qualify to be the substitute for the fallen humanity. In His role as fallen humanity’s substitute, He would die vicariously and at the same time have sin as a tendency rendered impotent. Jesus needed to assume a human nature that would qualify Him to be an understanding and sympathetic High Priest. He needed to assume a nature that would qualify Him to be an example in overcoming temptation and suffering. Thus, in this study, after comparing and critically evaluating the Christological views of Jack Sequeira, Millard J. Erickson and Norman R. Gulley, I propose that Jesus assumed a unique post-fall (postlapsarian) human nature. He assumed the very nature that all human beings since humankind’s fall have, with its tendency or leaning towards sin. However, unlike other human beings, who are sinners by nature and need a saviour, Jesus was not a sinner. I contend that Jesus was unique because, first and foremost, He was conceived in Mary’s womb by the power of the Holy Spirit and was filled with the Holy Spirit throughout His earthly life. Second; He was the God-Man; and third, He lived a sinless life. This study contributes to literature on Christology, and uniquely to Christological dialogue between Evangelical and Seventh-day Adventist theologians. / Philosophy, Practical and Systematic Theology / D. Phil. (Systematic Theology)