Little is known about the pathophysiology of delusional infestation (DI), a psychodermatologic condition in which patients have a fixed, false belief of being infested with parasites or inanimate material in their skin, despite lack of objective evidence. Because some delusional states, such as schizophrenia and psychotic state in bipolar disorder have been found to be associated with brain structural and functional abnormalities, a literature review was conducted to summarize available data on structural and functional abnormalities that are found to be associated with DI. A review of the literature found cases of brain imaging studies in patients with primary DI, as well as patients with secondary DI. Accumulating evidence from the studies reviewed suggests that dysfunction of the fronto-striato-thalamo-parietal network may explain how delusions manifest in DI and suggest that DI has an organic etiology. Abnormalities in the striato-thalamo-parietal network may cause false sensations of infestation through dysfunction in visuo-tactile regulation, whereas abnormalities in the frontal region may impair judgement. Delusional infestation patients also exhibit increased activation of brain structures implicated in itch processing. Furthermore, patients at high risk for cerebrovascular disease who present with secondary DI may benefit from brain imaging studies to rule out brain ischemic insult.

Abstract Background Mutations in FLT3 result in activated tyrosine kinase activity, cell growth stimulation, and a poor prognosis among various subtypes of leukemia. The causes and timing of the mutations are not currently known. We evaluated the prevalence and timing of origin of FLT3 mutations in a population series of childhood leukemia patients from Northern California. Methods We screened and sequenced FLT3 mutations (point mutations and internal tandem duplications, ITDs) among 517 childhood leukemia patients, and assessed whether these mutations occurred before or after birth using sensitive "backtracking" methods. Results We determined a mutation prevalence of 9 of 73 acute myeloid leukemias (AMLs, 12%) and 9 of 441 acute lymphocytic leukemias (ALLs, 2%). Among AMLs, FLT3 mutations were more common in older patients, and among ALLs, FLT3 mutations were more common in patients with high hyperdiploidy (3.7%) than those without this cytogenetic feature (1.4%). Five FLT3 ITDs, one deletion mutation, and 3 point mutations were assessed for their presence in neonatal Guthrie spots using sensitive real-time PCR techniques, and no patients were found to harbor FLT3 mutations at birth. Conclusions FLT3 mutations were not common in our population-based patient series in California, and patients who harbor FLT3 mutations most likely acquire them after they are born.