Does the Right Focal Variant of Alzheimer's Disease Really Exist? A Literature Analysis

Background: Alzheimer's disease (AD) is a clinically heterogeneous disease. Multiple atypical syndromes, distinct from the usual amnesic phenotype, have been described. In this context, the existence of a right variant of AD (RAD), characterized by enduring visuospatial impairment associated with right-sided asymmetric brain damage, has been proposed. However, to date, this phenotype remains controversial. In particular, its peculiar characteristics and the independence from more prevalent cases (especially the posterior cortical atrophy syndrome) have to be demonstrated. Objective: To explore the existence of focal RAD on the basis of existing literature. Methods: We performed a literature search for the description of atypical AD presentations, potentially evoking cases of focal RAD. To be considered as affected by RAD, the described cases had to present: 1) well documented right-sided asymmetry at neuroimaging; 2) predominant cognitive deficits localizable on the right hemisphere; 3) no specific diagnosis of a known variant of AD. Results: Twenty-one cases were found in the literature, but some of them were subsequently excluded because some features of a different clinical syndrome were overlapped with the clinical features of RAD. Thirteen positive cases, three of them with pathologically confirmed AD, remained. A common right clinical-radiological syndrome, characterized by memory and visuospatial impairment with temporal and parietal involvement, consistently emerged. However, the heterogeneity among the reports prevented a definitive and univocal description of the syndrome. Conclusion: Even if sporadic observations strongly support the existence of a focal RAD, no definitive conclusions can still be drawn about it as an independent condition

Familial late-onset Alzheimer's disease: description of an Italian family with four affected siblings and one case of early-onset dementia in the preceding generation

We describe a family composed of six siblings, four of which affected by late-onset Alzheimer's disease (LOAD). We constructed the family pedigree, evaluated mutations usually associated with early-onset Alzheimer's disease (APP, PSEN1, PSEN2), and assessed polymorphisms in the apolipoprotein E (APOE) gene and in cytokine genes that we had previously found to be associated with a higher risk of LOAD (IL-10, IL-6, TNF-\u3b1). Results showed that all subjects carried one \u3b54 allele of the APOE gene and those with the earliest age of onset exhibited the AA (-1082) IL-10 and the CC (-174) IL-6 genotypes. The only male had a genetic profile which also included the A (-308) TNF-\u3b1 allele. These data confirm the role of the APOE gene as genetic risk factor in LOAD, and suggest that the risk of developing AD may be governed by a "susceptibility profile" involving polymorphisms in inflammatory genes