Atypical presentations of Alzheimer's disease (AD) have been described, including a "frontal" variant (fvAD), which presents with personality change and executive dysfunction similar to that seen in behavioral variant frontotemporal dementia (bvFTD). This clinical variation is thought to reflect the regional distribution of pathology, although few reports include autopsy confirmation. We compared three clinicopathological groups matched for age at diagnosis and disease duration; those with possible bvFTD who at autopsy had only AD (fvAD), those with typical AD clinically and pathologically, and those with typical clinical bvFTD confirmed pathologically. The density of neurons and AD-type pathology was quantified in the frontal association, occipital association, and entorhinal cortices and hippocampal CA1 regions. Immunohistochemistry for phosphorylated tau and amyloid-β deposition was used to detect neurofibrillary tangles and plaques. Of the six core clinical features of the International Consensus Criteria, disinhibition, stereotyped behaviors, and executive dysfunction were most common, occurring in five of the six fvAD patients. Other features were rare. While there was no significant difference in neuron density between groups for any of the four regions, when the ratio of frontal:occipital pathology was examined, neuronal density in fvAD was significantly less than AD but similar to bvFTD. The frontal:occipital ratio of AD-type pathology was also greater in fvAD than AD. The findings of this study suggest a frontal variant of AD exists with features that mimic bvFTD and that this reflects a differential distribution of neurodegeneration with more marked pathology in the frontal cortex compared with the occipital cortex.

CYP2D6 genotype is not a determinant of susceptibility to acute dystonic reactions but may be a contributory factor in antipsychotic drug-induced movement disorders including tardive dyskinesia.

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare and potentially lethal disease characterized by fragmentary hemolysis, moderate-to-severe thrombocytopenia, end-organ dysfunction, and severely reduced ADAMTS13 levels (< 10%). Survival in iTTP has improved significantly since the introduction of plasma exchange as standard therapy combined with immune suppression to address the underlying pathophysiology. A host of challenges remain including prompt recognition of the disease, treatment of the end-organ effects of the disease, improving the early mortality rate, significantly reducing the relapse rate as well as addressing refractory disease. Discussed in this narrative review of iTTP are the recent measures aimed at addressing these issues, including improvements in clinical prediction models, postremission maintenance approaches with early retreatment as well as the development of novel therapies.

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