RESUMO
Autism spectrum disorder (ASD) is characterized by repetitive behaviors and deficits in social interaction. Its etiology is not completely clear, but both genetic and environmental factors contribute to and influence its development and course. The increased number of autism cases in recent years has been strongly associated with increased exposure to heavy metals. Mercury (Hg) has gained prominence in the scientific literature as a result of its presence as an urban pollutant and well-described neurotoxicity. This review assessed the relationship between Hg exposure in the pre- and post-natal period and ASD. The systematic review identified observational clinical studies and pre-clinical trials in journals indexed in the PubMed, Embase, ProQuest, and LILACS databases. The aim of this study was to investigate the association between exposure to Hg and ASD and to define the critical period of exposure. A total of 57 articles were selected for this review, with 35 articles (61.40%) identifying a positive association between ASD and Hg, while 22 articles (38.60%) did not find the same outcome. The biological samples most used to analyze Hg body burdens were hair (36.84%) and blood (36.84%). Most case-control studies found an increase in Hg levels in individuals with ASD who were exposed to a polluted environment in the post-natal period. Taken together, the studies suggest that these patients have a deficient detoxification system, and this could worsen the symptoms of the disorder. However, new studies addressing the influence of Hg on the post-natal nervous system and its relationship with ASD should be carried out.
RESUMO
The Bacille Calmette-Guerin (BCG) vaccine is one of the most widely used vaccines in the world for the prevention of tuberculosis. Its immunological capacity also includes epigenetic reprogramming, activation of T cells and inflammatory responses. Although the main usage of the vaccine is the prevention of tuberculosis, different works have shown that the effect of BCG can go beyond the peripheral immune response and be linked to the central nervous system by modulating the immune system at the level of the brain. This review therefore aims to describe the BCG vaccine, its origin, its relationship with the immune system, and its involvement at the brain level.
RESUMO
ABSTRACT Chromosomal abnormalities are responsible for several congenital malformations in the world, some of these are associated to telomeric/subtelomeric deletions. The abnormalities involving the telomere of chromosome 12 are rare, with few reports of deletions involving 12q24.31 region in the literature, and, to our knowledge, only four of them in the 12q24.31-q24.33 region. We report a further case of interstitial deletion of bands 12q24.31-q24.33 associated with autism spectrum disorder. A 2-year-old boy with global developmental delay associated with multiple congenital anomalies. The Human Genome CGH Microarray 60K confirmed the diagnosis of 12q deletion syndrome. This study made a review of the current literature comparing our patient with previously reported cases. These detailed analyses contribute to the development of genotype/phenotype correlations for 12q deletions that will aid in better diagnosis and prognosis of this deletion.
RESUMO Anomalias cromossômicas são responsáveis por inúmeras malformações congênitas no mundo, algumas delas associadas a deleções teloméricas/subteloméricas. As anomalias que envolvem o telômero do cromossomo 12 são raras, com poucos relatos na literatura sobre deleções relacionados à região 12q24.31 e, até onde sabemos, apenas quatro deles na região 12q24.31-q24.33. Relatamos um outro caso de deleção intersticial das bandas 12q24.31-q24.33 associada ao transtorno do espectro do autismo. Trata-se de um menino de 2 anos de idade com atraso global no desenvolvimento associado a múltiplas anomalias congênitas. A utilização do Human Genome CGH Microarray 60K confirmou o diagnóstico da síndrome de deleção 12q. Este estudo fez uma revisão da literatura atual, comparando nosso paciente com casos previamente relatados. Estas análises detalhadas contribuem para o desenvolvimento de correlações genótipo/fenótipo para deleções 12q, que ajudam aos melhores diagnóstico e prognóstico desta deleção.