Boganmeldelser

Book review

Genetic correlation between amyotrophic lateral sclerosis and schizophrenia

A. Palotie on työryhmän Schizophrenia Working Grp Psychiat jäsen.We have previously shown higher-than-expected rates of schizophrenia in relatives of patients with amyotrophic lateral sclerosis (ALS), suggesting an aetiological relationship between the diseases. Here, we investigate the genetic relationship between ALS and schizophrenia using genome-wide association study data from over 100,000 unique individuals. Using linkage disequilibrium score regression, we estimate the genetic correlation between ALS and schizophrenia to be 14.3% (7.05-21.6; P = 1 x 10(-4)) with schizophrenia polygenic risk scores explaining up to 0.12% of the variance in ALS (P = 8.4 x 10(-7)). A modest increase in comorbidity of ALS and schizophrenia is expected given these findings (odds ratio 1.08-1.26) but this would require very large studies to observe epidemiologically. We identify five potential novel ALS-associated loci using conditional false discovery rate analysis. It is likely that shared neurobiological mechanisms between these two disorders will engender novel hypotheses in future preclinical and clinical studies.Peer reviewe

Multi-Scale Segmentation of Grey-Scale Images

The topic of this thesis is segmentation of grey--scale images by accessing and relating the structures of the image for all reasonable scales. Grey--scale images are regarded as physical measurements obtained by an ensemble of detectors with finite aperture and finite readout precision. Based on this point of view, the notion of image is established using linear Gaussian scale space and Morse theory. The problem of segmentation is addressed within the framework of linear Gaussian scale space. The image at a given scale is partitioned according to a dissimilarity measure. Each minimum in the measure corresponds to exactly one segment. The segment is defined as the catchment basin belonging to the minimum. The gradient squared is used as the measure of dissimilarity. An essential part of the scale--space paradigm is to study the family of images indexed by scale as a family and not as a distinct set of images. The structure of the segments across scale are analysed exploiting the establ..