Correlação entre o polimorfismo thr92ala da enzima iodotironina desiodase tipo II e funções cognitivas na Síndrome de Down

• Ano de defesa: 2017
• Autor(a) principal: Batistuzzo, Alice
• Orientador(a): Ribeiro, Miriam Oliveira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Presbiteriana Mackenzie
• Palavras-chave em Português: polimorfismo; memória; inteligência; comportamento adaptativo
• Área do conhecimento CNPq: CNPQ::CIENCIAS HUMANAS::PSICOLOGIA
• Link de acesso: http://dspace.mackenzie.br/handle/10899/22726

About 12 to 36% of the population presents homozygosis for a polymorphism in enzyme deiodinase type 2 (Thr92Ala-D2). Positive correlations were found between point mutations in D2 and intellectual disability, bipolarity and psychosis. It has recently been shown that this mutation leads to modifications in the cellular transcriptome in human brains that appear to relate to changes in pathways involved in the modulation of cognitive development and in Parkinson's disease, Alzheimer's and schizophrenia. Down Syndrome (DS) is the most common autosomal aneuploidy, affecting on average 1/660 newborns and represents about 18% of the total number of mentally handicapped in specialized institutions. In addition to cognitive deficits, neuropathologies such as Alzheimer's in individuals with DS are frequent. Based on the data described, we asked whether the Thr92Ala-D2 mutation could contribute to changes in the cognitive functions of individuals with DS. To answer this question, the presence of Thr92Ala-D2 in 29 children with DS, aged between 2 months and 18 years, was screened. The genotype was determined by the PCR en real time technique. The IQ was estimated in 15 participants by the SON-R 2 ½ - 7 and WASI instruments. The short-term memory was evaluated in 11 participants from the TIME instrument and the adaptive behavior was evaluated in 29 through the Vineland Questionnaire. The frequency found for the genotype was 20.69% wild (T / T), 55.17% heterozygous (A / T) and 24.14% polymorphic (A / A) and similar to that found in the population In the adaptive behavior, a significant difference was found between the A / A polymorphic group and the wild T / T in the domains Domestic, Interpersonal Relations, Play and Leisure and in the Social and Global Adaptive Level domains. The IQ values ranged from 40 to 70, and in the evaluation of short-term memory, 72.72% of the subjects had a low performance. No correlation was found between the presence of polymorphism and IQ or memory. In future studies, it is important to use a larger sample, with young and adult individuals, and to compare with individuals of typical development, since strong evidence has been found in this study that the presence of polymorphism causes impairment in the cognitive functions of individuals with DS.