Autism Research Today is a free monthly online journal that collates and summarizes the latest research about Autism, including details on symptoms, diagnosis, treatment, causes, effects.

Effects of updating linkage evidence across subsets of data: reanalysis of the autism genetic resource exchange data set.

Bartlett CW, Goedken R, Vieland VJ

Center for Statistical Genetics Research, College of Public Health, and Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA. christopher-bartlett@uiowa.edu

Results of autism linkage studies have been difficult to interpret across research groups, prompting the use of ever-increasing sample sizes to increase power. However, increasing sample size by pooling disparate collections for a single analysis may, in fact, not increase power in the face of genetic heterogeneity. Here, we applied the posterior probability of linkage (PPL), a method designed specifically to analyze multiple heterogeneous data sets, to the Autism Genetic Resource Exchange collection of families by analyzing six clinically defined subsets of the data and updating the PPL sequentially over the subsets. Our results indicate a substantial probability of linkage to chromosome 1, which had been previously overlooked; our findings also provide a further characterization of the possible parent-of-origin effects at the 17q11 locus that were previously described in this sample. This analysis illustrates that the way in which heterogeneity is addressed in linkage analysis can dramatically affect the overall conclusions of a linkage study.

Published 4 March 2005 in Am J Hum Genet, 76(4): 688-95.
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