Genealogical investigation of a large Norwegian family (F04) with autosomal dominant parkinsonism has identified 18 affected family members over four generations. Genetic studies have revealed a novel pathogenic LRRK2 mutation c.4309 C>A (p.Asn1437His) that co-segregates with disease manifestation (LOD=3.15, θ=0). Affected carriers have an early age at onset (48 ± 7.7 SD years) and are clinically asymmetric and levodopa-responsive. The variant was absent in 623 Norwegian control subjects. Further screening of patients from the same population identified one additional affected carrier (1/692) with familial parkinsonism who shares the same haplotype. The mutation is located within the Roc domain of the protein and enhances GTP-binding and kinase activity, further implicating these activities as the mechanisms that underlie LRRK2-linked parkinsonism.

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Presently, bed-side or at home quantification of neutrophils in blood (b-neutrophils) is not practical, because cytometric methods are too expensive and technically demanding. We have explored whether calprotectin concentration in whole blood (b-calprotectin) might be a valid measure of b-neutrophils because this principle might be used in a simple and robust immunoassay device. We obtained heparin blood samples from 77 patients with possible neutropenia, most of them cancer patients treated with cytostatic drugs, and compared b-calprotectin with their b-neutrophils in a simultaneously taken EDTA-blood sample. The Spearman rank correlation coefficient between b-calprotectin and b-neutrophils was 0.986 (p < .0001). In a regression model of b-neutrophils as a function of age, gender, type of hematology instrument, total leukocyte count minus neutrophils, b-calprotectin, and plasma calprotectin (p-calprotectin), only b-calprotectin was a statistically significant predictor. B-neutrophils below 1 Â 10 9 /L was unlikely if b-calprotectin was above 50 mg/L. In conclusion, b-calprotectin, without adjusting for p-calprotectin, correlates closely with b-neutrophils and could be used to detect b-neutrophils below 1 Â 10 9 /L.