Journal of Alzheimer’s Disease 6 (2004) 391–395 391 IOS Press Apolipoprotein E4 allele and ribosomal genes in Alzheimer’s disease Wagner Malag´ o Tavares a , Marcia Aparecida Speranc¸a a , Roger Willian de Labio a , Clovis A. Peres d , Ivan Hideyo Okamoto c , Paulo Henrique Ferreira Bertolucci c , Mar´ılia de A.C. Smith b and Spencer Luiz Marques Pay ˜ ao a,b,∗ a Disciplina de Biologia Molecular, Hemocentro FAMEMA, Faculdade de Medicina de Mar´ılia, Mar´ılia, S ˜ ao Paulo, Brasil b Departamento de Morfologia, UNIFESP Escola Paulista de Medicina, S ˜ ao Paulo, Brasil c Departamento de Neurologia Cl´ınica, UNIFESP Escola Paulista de Medicina, S ˜ ao Paulo, Brasil d Departamento de Medicina Preventiva, UNIFESP Escola Paulista de Medicina, S ˜ ao Paulo, Brasil Abstract. Ribosomal genes are involved in cellular transcription, translation and gene expression modulation process. An association between 28S/18S rRNA ratio levels with apoptosis and aging has been reported. Moulder et al. [22] and Hashimoto et al. [8] showed an association between apolipoprotein E4 allele and neuronal cell apotosis through diverse mechanisms. The apoE 4 allele is considered a late-onset Alzheimer’s disease (AD) risk factor associated with AD pathogenesis. We evaluated the association between apoE4 allele genotyping by PCR and rRNA 28S/18S ratio by slot blotting technique using peripheral blood samples of 18 Alzheimer’s disease patients, 18 elderly controls and 18 young controls. A rRNA ratio decrease was observed in AD individuals confirming our previous results but this association is independently of the ApoE4 allele genotype. Thus our results pointed that two different mechanisms are involved in the etiology of Alzheimer disease each one leading independently to cell death. Further studies could investigate these factors. Keywords: Ageing, Alzheimer’s disease, Ribosomal genes, apolipoprotein E, 28S/18SrRNA 1. Introduction Alzheimer’ disease (AD) is an irreversible neurode- generative disorder being the most common form of dementia in elderly individuals over the age of 40 [12]. Pathologically, AD is mainly characterized by brain accumulation of neurofibrillary tangles (NFT) and se- nile plaques composed by amyloid β (Aβ). These al- terations are associated with progressive neuronal de- struction [34]. Mechanisms underlying the etiology of AD are not completely elucidated since it is a multifactorial dis- ∗ Corresponding author: Spencer Luiz Marques Pay˜ ao (PhD), Laborat´ orio de Citogen´ etica e Biologia Molecular, Hemocentro, Famema, Rua Lourival Freire, 240, Bairro Fragata, CEP 17519-050, Mar´ılia, S˜ ao Paulo, Brazil. Tel.: +55 14 42 11 856; Fax: +55 14 433 0148; E-mail: slmpayao@famema.br. ease with sporadic and familial cases involving onset in presenile (below 60 years old) or senile (over 65 years old) individuals. Genetic studies of AD familial cases at early onset lead to the description of mutations in three major genes: amyloid β-protein precursor protein (AβPP), presenilin 1 (PS1) and presenilin 2 (PS2) [1, 28]. However, sporadic and familial cases of AD with late onset which represent more than 98% of all forms of the disease are, potentially, caused by interaction of many genes in conjuction with environmental fac- tors. In these cases the allele ε4 of the apolipoprotein E (apoE-ε4) gene has been identified as the foremost AD genetic risk factor [20]. The apoE is a protein involved in lipid transport re- lated to different tissues, including the central nervous system and in AD patients it is associated with neurofib- rillary tangles and amyloid β (Aβ) senile plaques [2, 19]. The gene encoding apoE is located on chromo- ISSN 1387-2877/04/$17.00  2004 – IOS Press and the authors. All rights reserved