Alzheimer disease (AD) is the most frequent cause of dementia in Western countries. Putative genetic risk factors for AD are polymorphisms in the apolipoprotein E (APOE) gene and in the low-density lipoprotein receptor-related protein (LRP) gene. Our objective was to investigate the role of the APOE coding region polymorphisms e2, e3, and e4 and APOE promoter variants A/T at position -491 and G/T at -219, as well as LRP polymorphism C/T, as risk factors for AD in Brazilian individuals. One hundred and twenty patients with probable AD, along with 120 controls were analyzed. A significant difference between patients and controls for e4 alleles was observed: frequency of this allele in AD was 0.31, and 0.10 in controls. Individuals with 2 e4 alleles had a higher risk for AD than subjects with only 1 such allele; presence of 1 e2 allele proved protective. The presence of the T allele of the -219 polymorphism was also associated with an increased risk of AD, but this polymorphism is in linkage disequilibrium with APOE e polymorphisms. No significant differences between patients and controls were observed for -491 APOE or LRP polymorphisms. In this Brazilian population, both the e4 allele and T -219 polymorphism were associated with an increased risk for AD.

Medulloblastoma is the most common childhood malignant tumor of central nervous system, but it may also occur in adults. It presents high invasive growth with spreading of tumor cells into the leptomeningeal space along the neuroaxis early in the course of the disease. Extraneural metastases are rare but frequently lethal, occurring only in 1 to 5% of patients, and are related, in the most of cases, to the presence of ventriculoperitoneal shunt. Here we characterize the clinical profile of five cases of medulloblastoma with systemic spreading of tumor cells, also comparing them to cases already described in the literature. Key words: medulloblastoma, metastasis, extraneural.Mestástases extraneurais em moduloblastoma RESUMO O meduloblastoma é o tumor maligno mais frequente do sistema nervoso central na infância, mas também pode ocorrer em adultos. Ele apresenta crescimento altamente invasivo com disseminação de células tumorais ao longo do neuroeixo precocemente no curso da doença. Metástases extraneurais são raras mas frequentemente letais, ocorrendo apenas em 1 a 5% dos pacientes, e estão relacionadas, na maioria dos casos, a presença de derivação ventriculperitoneal. Neste artigo ,apresentamos o perfil de cinco casos de meduloblastoma com disseminção sistêmica das células tumorais, comparando-os com os casos já descritos na literatura. Palavras-chave: medulloblastoma, metastases, extraneural.