Kawasaki disease (KD) is the most common cause of paediatric acquired heart disease which may be attributed to the combined effects of infection, immunological response, and genetic susceptibility. Acute coronary artery lesions (CALs) develop in 20-48 % KD children. In addition, chronic CALs develop in approximately 20-30% of untreated KD children. Although KD children treated with IVIG, 2-6% still develop chronic CALs. According to recent epidemiological studies, Asian populations have a much higher incidence of KD. Taiwan has the third highest annual incidence in the world (69 per 100,000 children < 5 years of age between 2003 and 2006). Several studies have shown that KD patients spontaneously produce high levels of IL- 10. Plasma or serum IL-10 levels of KD children in acute phase were nearly 8-33 fold and 4-5 fold higher than those of healthy controls and those of the acute febrile children, respectively. The elevated IL-10 levels during the acute phase of KD not only decreased during subacute and convalescent phase, but also decreased immediately after IVIG administration, coincidently rapid improvement of inflammatory symptoms. The above studies show a correlation of high IL-10 levels with inflammatory features of KD, but do not answer the question of whether high levels of IL-10 may be simply a byproduct of acute KD, or whether it may play a role in the pathogenesis of KD. Therefore, a family-based linkage study of 134 case-parents trios, a case-control study of 247 KD children and 129 normal controls, and a matched case-control study of 76 KD cases with acute coronary artery lesions (CALs) and 76 KD controls without acute CALs were carried out to evaluate the association of genetic single nucleotide polymorphisms (SNP) in IL-10 promoter (-1082, -819, and -592) with the risk of KD and acute CALs. Based on the Transmission Disequilibrium test (TDT) results, significant undertransmission of haplotype ATA and overtransmission of haplotype (ACC+GCC) were found for KD (p = 0.023 and 0.011, respectively), even after 1,000 times permutation (p = 0.026 and 0.010, respectively). In addition, the TC and CC genotype of IL-10-819T>C were significantly associated with the decreased risk of acute CALs (AOR, 0.93; 95% CI, 0.47-1.81 and AOR, 0.07; 95% CI, 0.01-0.62, respectively), as compared to TT genotype. The carries of AC and CC genotype in IL-10-592A>C were with significantly decreased risk of acute CALs (AOR, 0.90; 95%CI, 0.46-1.75 and AOR, 0.17; 95%CI, 0.03-0.87, respectively), as compared to those with AA genotype. Furthermore, as compared with ATA/ATA diplotype, GCC+ACC/GCC+ACC diplotype of IL10 was associated with the decreased risk of acute CALs (AOR, 0.18; 95% CI, 0.04-0.72). In conclusion, the haplotype and diplotype of IL10-1082/-819/-592 were significant differences in the transmission in KD families and that the IL10-819 and -592 SNPs played important role for the sequelae of acute CALs.

<p>The breakdown of self-tolerance is the main driving force behind susceptibility to SLE. When this occurs, T and B cells are activated in an uncontrolled manner and produce autoantibodies against self fragmented DNA, RNA and sometimes other parts of the cell such as cardiolipin, phosphatidylserine, etc.</p><p>The mechanism behind the breakdown of self-tolerance may be genetic factors that are triggered by environmental factors. SLE is not caused by a single gene, but by many genes, and is thus a polygenic disease. So far only a few genes have been found to be associated with SLE including PDCD1, FcγRs, and PTPN22. The main aim of my thesis is to find susceptibility genes responsible for SLE.</p><p>Recently, a gene called IRF5 was found to be associated with SLE. In paper one, we performed a thorough study and confirmed its association to SLE. In addition, we found a few other SNPs in the gene that were associated to the disease. Among them, SNP rs2004640 is very strongly associated and was found to affect the splicing of the gene. Another SNP, rs2280714, correlated with overexpression of the gene, although SNP rs10954213 was much more highly correlated with expression adding to this, in paper two we found a few other SNPs that were associated to SLE and played crucial roles in gene function. An indel in exon 6, though not associated by itself, regulated which isoforms were expressed. Individuals with 2 repeats expressed isoforms V1 and V4, while individuals with 4 repeats expressed isoforms V5 and V6. SNP rs2070197 was also very strongly associated, but did not have a functional role. In paper three, the same polymorphisms were studied in a Mexican population, which showed an even stronger association when compared to a European population.</p><p>It is known that autoimmune diseases share susceptibility genes, therefore we wanted to see if the IRF5 gene is associated with any other autoimmune diseases. In papers four and five, we tested its association to RA (using three sets of patients and controls from Sweden, Argentina and Spain) and psoriasis (using a set of patients and controls from Sweden). Association was not found in either of the diseases. Therefore, we believe that this association may be SLE-specific.</p>

The breakdown of self-tolerance is the main driving force behind susceptibility to SLE. When this occurs, T and B cells are activated in an uncontrolled manner and produce autoantibodies against self fragmented DNA, RNA and sometimes other parts of the cell such as cardiolipin, phosphatidylserine, etc. The mechanism behind the breakdown of self-tolerance may be genetic factors that are triggered by environmental factors. SLE is not caused by a single gene, but by many genes, and is thus a polygenic disease. So far only a few genes have been found to be associated with SLE including PDCD1, FcγRs, and PTPN22. The main aim of my thesis is to find susceptibility genes responsible for SLE. Recently, a gene called IRF5 was found to be associated with SLE. In paper one, we performed a thorough study and confirmed its association to SLE. In addition, we found a few other SNPs in the gene that were associated to the disease. Among them, SNP rs2004640 is very strongly associated and was found to affect the splicing of the gene. Another SNP, rs2280714, correlated with overexpression of the gene, although SNP rs10954213 was much more highly correlated with expression adding to this, in paper two we found a few other SNPs that were associated to SLE and played crucial roles in gene function. An indel in exon 6, though not associated by itself, regulated which isoforms were expressed. Individuals with 2 repeats expressed isoforms V1 and V4, while individuals with 4 repeats expressed isoforms V5 and V6. SNP rs2070197 was also very strongly associated, but did not have a functional role. In paper three, the same polymorphisms were studied in a Mexican population, which showed an even stronger association when compared to a European population. It is known that autoimmune diseases share susceptibility genes, therefore we wanted to see if the IRF5 gene is associated with any other autoimmune diseases. In papers four and five, we tested its association to RA (using three sets of patients and controls from Sweden, Argentina and Spain) and psoriasis (using a set of patients and controls from Sweden). Association was not found in either of the diseases. Therefore, we believe that this association may be SLE-specific.

Made available in DSpace on 2015-04-01T14:16:05Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 855713 bytes, checksum: c28b304561e6cf7b209782cd77c44bd9 (MD5) Previous issue date: 2014-08-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The MTHFR 677C>T variant (rs1801133) has been analysed as a putative genetic risk factor for oral clefts within various populations worldwide. To test the role of the MTHFR 677C>T variant in nonsyndromic cleft lip with or without cleft palate (NSCL/P) predisposition in the Brazilian population, we conducted a study combining a family-based association test (transmission disequilibrium test-TDT) and a structured association analysis (case-control study) based on the individual ancestry proportions. The rs1801133 polimorphism was genotyped in 197 trios with NSCL/P, 318 isolated samples of NSCL/P and 598 healthy controls using the TaqMan 5′- exonuclease allelic discrimination assay. Genomic ancestry was characterized by a set of 40 biallelic short insertion/deletion markers. TDT revealed a strong association of rs1801133 polymorphism with case-parent trios of NSCL/P (p=0.002) and non-syndromic cleft lip and palate (NSCLP, p=0.001), but not with non-syndromic cleft lip (NSCL). Analyses of parent-oforigin effects demonstrated modest excess transmission of the risk allele from mothers of NSCLP (OR: 1.47, 95% CI: 1.10-2.14, p=0.04). The structured case-control analysis supported these findings, revealing that the risk T allele was significantly more frequent in NSCL/P group (OR: 1.37, 95% CI: 1.12-1.69, p=0.002) and NSCLP (OR: 1.41, 95% CI: 1.12-1.79, p=0.01) than the control group. Our findings provide evidence for the involvement of rs1801133 in the development of NSCL/P in the Brazilian population, and reinforce the importance of genetic screening in populations at risk in order to optimize the implementation of preventive strategies. / Entre os prováveis fatores de risco genético para as fissuras orais, está o polimorfismo rs1801133 do gene MTHFR (677C>T). O papel desse polimorfismo com relação à predisposição para fissuras não-sindrômicas do lábio com ou sem o envolvimento do palato (FL/P) foi analisado na população Brasileira. Utilizou-se duas abordagens, um teste de associação de base familiar (teste de desequilíbrio de transmissão TDT) e um estudo casocontrole baseado nas proporções individuais de ancestralidade. Na análise TDT o polimorfismo rs1801133 foi genotipado em 197 trios (o afetado e seus respectivos pais). No estudo casocontrole foram incluídos 318 indivíduos fissurados e 598 controles não portadores de fissuras ou qualquer outra anomalia. Realizou-se ensaio de discriminação alélica TaqMan 5′- exonuclease. A ancestralidade genômica foi caracterizada por um conjunto de 40 marcadores bialélicos de curta inserção / deleção. O TDT revelou uma forte associação entre o polimorfismo rs1801133 nos trios de portadores de FL/P (p=0,002) como também nos trios de fissuras labiopalatinas (FLP, p=0,001), mas não apresentou associação com fissuras labiais isoladas (FL). A análise da origem parental do alelo T mostrou excesso de transmissão, por parte das mães, nos trios de portadores de FLP (OR: 1.47, 95%CI: 1.10-2.14, p=0,04). O estudo caso-controle corroborou com os resultados obtidos no TDT, demonstrando que o alelo polimórfico 677T foi significantemente mais frequente no grupo de portadores de FL/P (OR: 1.37, 95% CI: 1.12-1.69, p=0,002) e de FLP (OR: 1.41, 95% CI 1.12-1.79, p=0,01) quando comparada ao grupo controle. Em conclusão, o presente estudo sugere correlação entre o polimorfismo rs1801133 e o desenvolvimento de FL/P na população brasileira, e reforça a importância da triagem genética nas famílias dos afetados para otimizar a aplicação de medidas preventivas.