1. Laboratory of Genetics and Physiology (E.B.R., P.D., K.-U.W., L.H.) National Institute of Diabetes, Digestive and Kidney Diseases National Institutes of Health Bethesda, Maryland 20892
2. Genetic Disease Research Branch (L.G., A.W.-B.) National Human Genome Research Institute National Institutes of Health Bethesda, Maryland 20892
3. Department of Epidemiology and Preventive Medicine (J.A.F.) University of Maryland School of Medicine Baltimore, Maryland 21201