Navegando por Autor "Sena, Lucas Schenatto"
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Artigo Minimal prevalence of Huntington’s disease in the South of Brazil and instability of the expanded CAG tract during intergenerational transmissions(SciELO, 2019) Godeiro Junior, Clécio de Oliveira; Castilhos, Raphael Machado de; Santos, José Augusto dos; Augustin, Marina Coutinho Augustin; Pedroso, José Luiz; Barsottini, Orlando; Saba, Roberta; Ferraz, Henrique Ballalai; Vargas, Fernando Regla; Salarini, Diego Zanotti; Furtado, Gabriel Vasata; Polese-Bonatto, Marcia; Rodrigues, Luiza Paulsen; Sena, Lucas Schenatto; Saraiva-Pereira, Maria Luiza; Jardim, Laura Bannach; 0000-0002-4312-1633Huntington’s disease (HD) is due to dominant expansions of the CAG repeat of the HTT gene. Meiotic instability of the (CAG)n might impact the disorder frequency. We report on HD minimal prevalence in Rio Grande do Sul (RS) state, Brazil, and on intergenerational instability of the (CAG)n in HD families. Symptomatic and at-risk subjects from 179 HD families were ascertained between 2013 and 2016. Clinical, molecular and family history data were obtained. Expanded (CAG)n length differences between parent and child (delta-expanded-(CAG)n) were calculated. Effect of parental age on the (CAG)n instability upon transmission was inferred by correlating delta-expanded-(CAG)n between siblings to their age differences. HD minimal prevalence in RS state was estimated as 1.85:100,000 inhabitants. Alleles with (CAG)27-35 were found on 21/384 non-disease associated chromosomes (5.5%); among 253 expanded alleles, four (1.6%) were within reduced penetrance range with (CAG)36-39. In 32 direct transmissions, mean instability was larger among paternal than maternal transmissions. In direct transmissions and in 51 sibling pairs, parental age at the time of child birth were not correlated with delta-expanded-(CAG)n. Briefly, HD prevalence in RS state was lower than those reported for European populations. Expanded (CAG)n transmissions were unstable and not associated to parental age.Artigo Selective forces related to spinocerebellar ataxia type 2(Springer, 2018-09-15) Godeiro Junior, Clécio de Oliveira; Sena, Lucas Schenatto; Castilhos, Raphael Machado; Mattos, Eduardo Preusser; Furtado, Gabriel Vasata; Pedroso, José Luiz; Barsottini, Orlando; Amorim, Maria Marla Paiva de; Pereira, Maria Luiza Saraiva; Jardim, Laura Bannach; 0000-0002-4312-1633Spinocerebellar ataxia type 2 (SCA2) is caused by an unstable expanded CAG repeat tract (CAGexp) at ATXN2. Although prone to selective forces such as anticipation, SCA2 frequency seems to be stable in populations. Our aim was to estimate reproductive success, segregation patterns, and role of anticipation in SCA2. Adult subjects from families with molecular diagnosis provided data about all his/her relatives. Affected and unaffected sibs older than 65.7 years of age were used to estimate reproductive success and segregation patterns. Twenty-one SCA2 families were studied, including 1017 individuals (164 affected) who were born from 1840 to 2012. The median number of children of the non-carriers and carriers, among 99 subjects included in the reproductive success analysis, were 2 and 3 (p < 0.025), respectively. Therefore, the reproductive success of carriers was 1.5. There were 137 non-carriers (59.6%) and 93 carriers (40.4%) (p = 0.04), among subjects included in the segregation analysis. Age at onset across generations pointed to anticipation as a frequent phenomenon. We raised evidence in favor of increased reproductive success related to the carrier state at ATXN2, and segregation distortion favoring normal alleles. Since majority of normal alleles analyzed carried 22 repeats, we propose that this distortion segregation can be related to the high frequency of this allele in human chromosomes.