1. Medical Genomics Unit, Medical Genetics Branch, National Human Genome Research Institute , Bethesda, MA 20892, United States
2. Institute of Computer Science, Augsburg University , Augsburg, Bavaria 86159, Germany
3. Institute for Genomic Statistics and Bioinformatics, University of Bonn , Bonn, North Rhine-Westphalia 53113, Germany
4. Social and Behavioral Research Branch, National Human Genome Research Institute , Bethesda, MA 20892, United States